Diff for /loncom/interface/loncoursedata.pm between versions 1.34 and 1.201.2.3

version 1.34, 2002/10/09 17:25:23 version 1.201.2.3, 2021/03/02 20:00:50
Line 1 Line 1
 # The LearningOnline Network with CAPA  # The LearningOnline Network with CAPA
 # (Publication Handler  
 #  #
 # $Id$  # $Id$
 #  #
Line 26 Line 25
 # http://www.lon-capa.org/  # http://www.lon-capa.org/
 #  #
 ###  ###
   
 =pod  =pod
   
 =head1 NAME  =head1 NAME
   
 loncoursedata  Apache::loncoursedata
   
 =head1 SYNOPSIS  =head1 SYNOPSIS
   
Line 39  Set of functions that download and proce Line 37  Set of functions that download and proce
   
 =head1 PACKAGES USED  =head1 PACKAGES USED
   
  Apache::Constants qw(:common :http)    Apache::lonnet
  Apache::lonnet()    Apache::longroup
  Apache::lonhtmlcommon    Time::HiRes
  HTML::TokeParser    Apache::lonmysql
  GDBM_File    LONCAPA
     Digest::MD5
   
 =cut  =cut
   
 package Apache::loncoursedata;  package Apache::loncoursedata;
   
 use strict;  use strict;
 use Apache::Constants qw(:common :http);  use Apache::lonnet;
 use Apache::lonnet();  use Apache::longroup();
 use Apache::lonhtmlcommon;  use Time::HiRes();
 use HTML::TokeParser;  use Apache::lonmysql();
 use GDBM_File;  use LONCAPA;
   use Digest::MD5();
   
   =pod 
   
   =head2 make_into_hash
   
   Turn a colon separated string into a hash and return a reference
   to it.  Numbering from 0 even elements are keys and odd elements
   are values e.g. a:b:c:d creates a hash like
     a => b, c =>d
   
 =pod  =cut
   
 =head1 DOWNLOAD INFORMATION  sub make_into_hash {
       my $values = shift;
       my %tmp = map { &unescape($_); } split(':',$values);
       return \%tmp;
   }
   
 This section contains all the functions that get data from other servers   
 and/or itself.  
   
 =cut  { # Begin scope of table identifiers
   
 # ----- DOWNLOAD INFORMATION -------------------------------------------  my $current_course ='';
   my $symb_table;
   my $part_table;
   my $student_table;
   my $groupnames_table;
   my $students_groups_table;
   my $performance_table;
   my $parameters_table;
   my $fulldump_response_table;
   my $fulldump_part_table;
   my $fulldump_timestamp_table;
   my $weight_table;
   
   my @Tables;
   
   
   
   sub init_dbs {
       my ($courseid,$drop) = @_;
       &setup_table_names($courseid);
       #
       # Drop any of the existing tables
       if ($drop) {
           foreach my $table (@Tables) {
               &Apache::lonmysql::drop_table($table);
           }
       }
       #
       # Note - changes to this table must be reflected in the code that 
       # stores the data (calls &Apache::lonmysql::store_row with this table
       # id
       my $symb_table_def = {
           id => $symb_table,
           permanent => 'no',
           columns => [{ name => 'symb_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL',
                         auto_inc     => 'yes', },
                       { name => 'symb',
                         type => 'MEDIUMTEXT',
                         restrictions => 'NOT NULL'},
                       ],
           'PRIMARY KEY' => ['symb_id'],
       };
       #
       my $part_table_def = {
           id => $part_table,
           permanent => 'no',
           columns => [{ name => 'part_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL',
                         auto_inc     => 'yes', },
                       { name => 'part',
                         type => 'VARCHAR(100) BINARY',
                         restrictions => 'NOT NULL'},
                       ],
           'PRIMARY KEY' => ['part (100)'],
           'KEY' => [{ columns => ['part_id']},],
       };
       #
       my $student_table_def = {
           id => $student_table,
           permanent => 'no',
           columns => [{ name => 'student_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL',
                         auto_inc     => 'yes', },
                       { name => 'student',
                         type => 'VARCHAR(100) BINARY',
                         restrictions => 'NOT NULL UNIQUE'},
                       { name => 'section',
                         type => 'VARCHAR(100) BINARY',
                         restrictions => 'NOT NULL'},
                       { name => 'start',
                         type => 'INT',
                         restrictions => 'NOT NULL'},
                       { name => 'end',
                         type => 'INT',
                         restrictions => 'NOT NULL'},
                       { name => 'classification',
                         type => 'VARCHAR(100) BINARY', },
                       { name => 'updatetime',
                         type => 'INT UNSIGNED'},
                       { name => 'fullupdatetime',
                         type => 'INT UNSIGNED'},
                       ],
           'PRIMARY KEY' => ['student_id'],
           'KEY' => [{ columns => ['student (100)',
                                   'section (100)',
                                   'start',
    'end']},],
       };
       #
       my $groupnames_table_def = {
           id => $groupnames_table,
           permanent => 'no',
           columns => [{ name => 'group_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL',
                         auto_inc => 'yes', },
                       { name => 'groupname',
                         type => 'VARCHAR(100) BINARY',
                         restrictions => 'NOT NULL UNIQUE'},
                      ],
           'PRIMARY KEY' => ['group_id'],
           'KEY' => [{ columns => ['groupname (100)',]},],
       };
       #
       my $students_groups_table_def = {
           id => $students_groups_table,
           permanent => 'no',
           columns => [{ name => 'student_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL', },
                       { name => 'group_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL', },
                      ],
           'PRIMARY KEY' => ['student_id','group_id'],
           'KEY' => [{ columns => ['student_id'] },
                     { columns => ['group_id'] },],
       };
       #
       my $performance_table_def = {
           id => $performance_table,
           permanent => 'no',
           columns => [{ name => 'symb_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'student_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'part_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL' },
                       { name => 'part',
                         type => 'VARCHAR(100) BINARY',
                         restrictions => 'NOT NULL'},                    
                       { name => 'solved',
                         type => 'TINYTEXT' },
                       { name => 'tries',
                         type => 'SMALLINT UNSIGNED' },
                       { name => 'awarded',
                         type => 'REAL' },
                       { name => 'award',
                         type => 'TINYTEXT' },
                       { name => 'awarddetail',
                         type => 'TINYTEXT' },
                       { name => 'timestamp',
                         type => 'INT UNSIGNED'},
                       ],
           'PRIMARY KEY' => ['symb_id','student_id','part_id'],
           'KEY' => [{ columns=>['student_id'] },
                     { columns=>['symb_id'] },],
       };
       #
       my $fulldump_part_table_def = {
           id => $fulldump_part_table,
           permanent => 'no',
           columns => [
                       { name => 'symb_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'part_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL' },
                       { name => 'student_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'transaction',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL' },
                       { name => 'tries',
                         type => 'SMALLINT UNSIGNED',
                         restrictions => 'NOT NULL' },
                       { name => 'award',
                         type => 'TINYTEXT' },
                       { name => 'awarded',
                         type => 'REAL' },
                       { name => 'previous',
                         type => 'SMALLINT UNSIGNED' },
   #                    { name => 'regrader',
   #                      type => 'TINYTEXT' },
   #                    { name => 'afterduedate',
   #                      type => 'TINYTEXT' },
                       ],
           'PRIMARY KEY' => ['symb_id','part_id','student_id','transaction'],
           'KEY' => [
                     { columns=>['symb_id'] },
                     { columns=>['part_id'] },
                     { columns=>['student_id'] },
                     ],
       };
       #
       my $fulldump_response_table_def = {
           id => $fulldump_response_table,
           permanent => 'no',
           columns => [
                       { name => 'symb_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'part_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL' },
                       { name => 'response_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'student_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'transaction',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL' },
                       { name => 'awarddetail',
                         type => 'TINYTEXT' },
   #                    { name => 'message',
   #                      type => 'CHAR BINARY'},
                       { name => 'response_specific',
                         type => 'TINYTEXT' },
                       { name => 'response_specific_value',
                         type => 'TINYTEXT' },
                       { name => 'response_specific_2',
                         type => 'TINYTEXT' },
                       { name => 'response_specific_value_2',
                         type => 'TINYTEXT' },
                       { name => 'submission',
                         type => 'TEXT'},
                       ],
               'PRIMARY KEY' => ['symb_id','part_id','response_id','student_id',
                                 'transaction'],
               'KEY' => [
                         { columns=>['symb_id'] },
                         { columns=>['part_id','response_id'] },
                         { columns=>['student_id'] },
                         ],
       };
       my $fulldump_timestamp_table_def = {
           id => $fulldump_timestamp_table,
           permanent => 'no',
           columns => [
                       { name => 'symb_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'student_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'transaction',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL' },
                       { name => 'timestamp',
                         type => 'INT UNSIGNED'},
                       ],
           'PRIMARY KEY' => ['symb_id','student_id','transaction'],
           'KEY' => [
                     { columns=>['symb_id'] },
                     { columns=>['student_id'] },
                     { columns=>['transaction'] },
                     ],
       };
       #
       my $parameters_table_def = {
           id => $parameters_table,
           permanent => 'no',
           columns => [{ name => 'symb_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'student_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'parameter',
                         type => 'TINYTEXT',
                         restrictions => 'NOT NULL'  },
                       { name => 'value',
                         type => 'MEDIUMTEXT' },
                       ],
           'PRIMARY KEY' => ['symb_id','student_id','parameter (255)'],
       };
       #
       my $weight_table_def = {
           id => $weight_table,
           permanent => 'no',
           columns => [{ name => 'symb_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'part_id',
                         type => 'MEDIUMINT UNSIGNED',
                         restrictions => 'NOT NULL'  },
                       { name => 'weight',
                         type => 'REAL',
                         restrictions => 'NOT NULL'  },
                       ],
           'PRIMARY KEY' => ['symb_id','part_id'],
       };
       #
       # Create the tables
       my $tableid;
       $tableid = &Apache::lonmysql::create_table($symb_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating symb_table: ".
                                    &Apache::lonmysql::get_error());
           return 1;
       }
       #
       $tableid = &Apache::lonmysql::create_table($part_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating part_table: ".
                                    &Apache::lonmysql::get_error());
           return 2;
       }
       #
       $tableid = &Apache::lonmysql::create_table($student_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating student_table: ".
                                    &Apache::lonmysql::get_error());
           return 3;
       }
       #
       $tableid = &Apache::lonmysql::create_table($performance_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating preformance_table: ".
                                    &Apache::lonmysql::get_error());
           return 5;
       }
       #
       $tableid = &Apache::lonmysql::create_table($parameters_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating parameters_table: ".
                                    &Apache::lonmysql::get_error());
           return 6;
       }
       #
       $tableid = &Apache::lonmysql::create_table($fulldump_part_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating fulldump_part_table: ".
                                    &Apache::lonmysql::get_error());
           return 7;
       }
       #
       $tableid = &Apache::lonmysql::create_table($fulldump_response_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating fulldump_response_table: ".
                                    &Apache::lonmysql::get_error());
           return 8;
       }
       $tableid = &Apache::lonmysql::create_table($fulldump_timestamp_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating fulldump_timestamp_table: ".
                                    &Apache::lonmysql::get_error());
           return 9;
       }
       $tableid = &Apache::lonmysql::create_table($weight_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating weight_table: ".
                                    &Apache::lonmysql::get_error());
           return 10;
       }
       $tableid = &Apache::lonmysql::create_table($groupnames_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating groupnames_table: ".
                                    &Apache::lonmysql::get_error());
           return 11;
       }
       $tableid = &Apache::lonmysql::create_table($students_groups_table_def);
       if (! defined($tableid)) {
           &Apache::lonnet::logthis("error creating student_groups_table: ".
                                    &Apache::lonmysql::get_error());
           return 12;
       }
       return 0;
   }
   
 =pod  =pod
   
 =item &DownloadClasslist()  =head2 delete_caches
   
 Collects lastname, generation, middlename, firstname, PID, and section for each  Drops all of the tables in the local mysql cache associated with the
 student from their environment database.  The section data is also download, though  specified course id.
 it is in a rough format, and is processed later.  The list of students is built from  
 collecting a classlist for the course that is to be displayed.  Once the classlist  
 has been downloaded, its date stamp is recorded.  Unless the datestamp for the  
 class database is reset or is modified, this data will not be downloaded again.    
 Also, there was talk about putting the fullname and section  
 and perhaps other pieces of data into the classlist file.  This would  
 reduce the number of different file accesses and reduce the amount of   
 processing on this side.  
   
 =over 4  TODO:  The drops should be pushed into lonmysql to further isolate 
   mysql code from other modules.
   
 Input: $courseID, $lastDownloadTime, $c  =cut
   sub delete_caches {
       my $courseid = shift;
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       #
       &setup_table_names($courseid);
       #
       my $dbh = &Apache::lonmysql::get_dbh();
       foreach my $table (@Tables) {
           my $command = 'DROP TABLE '.$table.';';
           $dbh->do($command);
           if ($dbh->err) {
               &Apache::lonnet::logthis($command.' resulted in error: '.$dbh->errstr);
           }
       }
       return;
   }
   
 $courseID:  The id of the course  
   
 $lastDownloadTime:  This is the date stamp for when this information was  my $have_read_part_table = 0;
 last gathered.  If it is set to Not downloaded, it will gather the data  my %ids_by_part;
 again, though it currently does not remove the old data.  my %parts_by_id;
   
   sub get_part_id {
       my ($part) = @_;
       $part = 0 if (! defined($part));
       if (! $have_read_part_table) {
           my @Result = &Apache::lonmysql::get_rows($part_table);
           foreach (@Result) {
               $ids_by_part{$_->[1]}=$_->[0];
           }
           $have_read_part_table = 1;
       }
       if (! exists($ids_by_part{$part})) {
           &Apache::lonmysql::store_row($part_table,[undef,$part]);
           undef(%ids_by_part);
           my @Result = &Apache::lonmysql::get_rows($part_table);
           foreach (@Result) {
               $ids_by_part{$_->[1]}=$_->[0];
           }
       }
       return $ids_by_part{$part} if (exists($ids_by_part{$part}));
       return undef; # error
   }
   
 $c: The connection class that can determine if the browser has aborted.  It  sub get_part {
 is used to short circuit this function so that it does not continue to       my ($part_id) = @_;
 get information when there is no need.      if (! exists($parts_by_id{$part_id})  || 
           ! defined($parts_by_id{$part_id}) ||
           $parts_by_id{$part_id} eq '') {
           my @Result = &Apache::lonmysql::get_rows($part_table);
           foreach (@Result) {
               $parts_by_id{$_->[0]}=$_->[1];
           }
       }
       return $parts_by_id{$part_id} if(exists($parts_by_id{$part_id}));
       return undef; # error
   }
   
 Output: \%classlist  
   
 \%classlist: A pointer to a hash containing the following data:  my $have_read_symb_table = 0;
   my %ids_by_symb;
   my %symbs_by_id;
   
   sub get_symb_id {
       my ($symb) = @_;
       if (! $have_read_symb_table) {
           my @Result = &Apache::lonmysql::get_rows($symb_table);
           foreach (@Result) {
               $ids_by_symb{$_->[1]}=$_->[0];
           }
           $have_read_symb_table = 1;
       }
       if (! exists($ids_by_symb{$symb})) {
           &Apache::lonmysql::store_row($symb_table,[undef,$symb]);
           undef(%ids_by_symb);
           my @Result = &Apache::lonmysql::get_rows($symb_table);
           foreach (@Result) {
               $ids_by_symb{$_->[1]}=$_->[0];
           }
       }
       return $ids_by_symb{$symb} if(exists( $ids_by_symb{$symb}));
       return undef; # error
   }
   
 -A list of student name:domain (as keys) (known below as $name)  sub get_symb {
       my ($symb_id) = @_;
       if (! exists($symbs_by_id{$symb_id})  || 
           ! defined($symbs_by_id{$symb_id}) ||
           $symbs_by_id{$symb_id} eq '') {
           my @Result = &Apache::lonmysql::get_rows($symb_table);
           foreach (@Result) {
               $symbs_by_id{$_->[0]}=$_->[1];
           }
       }
       return $symbs_by_id{$symb_id} if(exists( $symbs_by_id{$symb_id}));
       return undef; # error
   }
   
 -A hash pointer for each student containing lastname, generation, firstname,  my $have_read_student_table = 0;
 middlename, and PID : Key is $name.studentInformation  my %ids_by_student;
   my %students_by_id;
   
   sub get_student_id {
       my ($sname,$sdom) = @_;
       my $student = $sname.':'.$sdom;
       if (! $have_read_student_table) {
           my @Result = &Apache::lonmysql::get_rows($student_table);
           foreach (@Result) {
               $ids_by_student{$_->[1]}=$_->[0];
           }
           $have_read_student_table = 1;
       }
       if (! exists($ids_by_student{$student})) {
           &populate_student_table();
           undef(%ids_by_student);
           undef(%students_by_id);
           my @Result = &Apache::lonmysql::get_rows($student_table);
           foreach (@Result) {
               $ids_by_student{$_->[1]}=$_->[0];
           }
       }
       return $ids_by_student{$student} if(exists( $ids_by_student{$student}));
       return undef; # error
   }
   
 -A hash pointer to each students section data : Key is $name.section  sub get_student {
       my ($student_id) = @_;
       if (! exists($students_by_id{$student_id})  || 
           ! defined($students_by_id{$student_id}) ||
           $students_by_id{$student_id} eq '') {
           my @Result = &Apache::lonmysql::get_rows($student_table);
           foreach (@Result) {
               $students_by_id{$_->[0]}=$_->[1];
           }
       }
       return $students_by_id{$student_id} if(exists($students_by_id{$student_id}));
       return undef; # error
   }
   
 -If there was an error in dump, it will be returned in the hash.  See  sub populate_student_table {
 the error codes for dump in lonnet.  Also, an error key will be       my ($courseid) = @_;
 generated if an abort occurs.      if (! defined($courseid)) {
           $courseid = $env{'request.course.id'};
       }
       #
       &setup_table_names($courseid);
       &init_dbs($courseid,0);
       my $dbh = &Apache::lonmysql::get_dbh();
       my $request = 'INSERT IGNORE INTO '.$student_table.
           "(student,section,start,end) VALUES ";
       my $cdom = $env{'course.'.$courseid.'.domain'};
       my $cnum = $env{'course.'.$courseid.'.num'};
       my $classlist = &get_classlist($cdom,$cnum);
       my $student_count=0;
       while (my ($student,$data) = each %$classlist) {
           my ($section,$start,$end) = ($data->[&CL_SECTION()],
        $data->[&CL_START()],
        $data->[&CL_END()]);
           if ($section eq '' || $section =~ /^\s*$/) {
               $section = 'none';
           }
    if (!defined($start)) { $start = 0; }
    if (!defined($end))   { $end   = 0; }
           $request .= "('".$student."','".$section."','".$start."','".$end."'),";
           $student_count++;
       }
       return if ($student_count == 0);
       chop($request);
       $dbh->do($request);
       if ($dbh->err()) {
           &Apache::lonnet::logthis("error ".$dbh->errstr().
                                    " occurred executing \n".
                                    $request);
       }
       return;
   }
   
 =back  my $have_read_groupnames_table = 0;
   my %ids_by_groupname;
   
 =cut  sub get_group_id {
       my ($groupname) = @_;
       if (! $have_read_groupnames_table) {
           my @Result = &Apache::lonmysql::get_rows($groupnames_table);
           foreach (@Result) {
               $ids_by_groupname{$_->[1]}=$_->[0];
           }
           $have_read_groupnames_table = 1;
       }
       if (! exists($ids_by_groupname{$groupname})) {
           &populate_groupnames_table();
           undef(%ids_by_groupname);
           my @Result = &Apache::lonmysql::get_rows($groupnames_table);
           foreach (@Result) {
               $ids_by_groupname{$_->[1]}=$_->[0];
           }
       }
       if (exists($ids_by_groupname{$groupname})) {
           return $ids_by_groupname{$groupname};
       }
       return undef; # error
   }
   
 sub DownloadClasslist {  sub populate_groupnames_table {
     my ($courseID, $lastDownloadTime, $c)=@_;      my ($courseid) = @_;
     my ($courseDomain,$courseNumber)=split(/\_/,$courseID);      if (! defined($courseid)) {
     my %classlist;          $courseid = $env{'request.course.id'};
       }
     my $modifiedTime = &Apache::lonnet::GetFileTimestamp($courseDomain, $courseNumber,      &setup_table_names($courseid);
                                                          'classlist.db',       &init_dbs($courseid,0);
                                                          $Apache::lonnet::perlvar{'lonUsersDir'});      my $dbh = &Apache::lonmysql::get_dbh();
       my $cdom = $env{'course.'.$courseid.'.domain'};
     # Always download the information if lastDownloadTime is set to      my $cnum = $env{'course.'.$courseid.'.num'};
     # Not downloaded, otherwise it is only downloaded if the file      my %curr_groups = &Apache::longroup::coursegroups($cdom,$cnum);
     # has been updated and has a more recent date stamp      return if (!%curr_groups);
     if($lastDownloadTime ne 'Not downloaded' &&      my $request = 'INSERT IGNORE INTO '.$groupnames_table.
        $lastDownloadTime >= $modifiedTime && $modifiedTime >= 0) {                    '(groupname) VALUES ';
         # Data is not gathered so return UpToDate as true.  This      foreach my $groupname (sort(keys(%curr_groups)),'none') {
         # will be interpreted in ProcessClasslist          $request .= "('".$groupname."'),";
         $classlist{'lastDownloadTime'}=time;      }
         $classlist{'UpToDate'} = 'true';      chop($request);
         return \%classlist;      $dbh->do($request);
       if ($dbh->err()) {
           &Apache::lonnet::logthis("error ".$dbh->errstr().
                                    " occurred executing \n".
                                    $request);
     }      }
       return;
   }
   
     %classlist=&Apache::lonnet::dump('classlist',$courseDomain, $courseNumber);  my $have_read_studentsgroups_table = 0;
     foreach(keys (%classlist)) {  my %groupids_by_studentid;
         if(/^(con_lost|error|no_such_host)/i) {  
     return;  sub get_students_groupids {
       my ($student_id) = @_;
       if (! $have_read_studentsgroups_table) {
           my @Result = &Apache::lonmysql::get_rows($students_groups_table);
           foreach (@Result) {
               push(@{$groupids_by_studentid{$_->[0]}},$_->[1]);
         }          }
           $have_read_studentsgroups_table = 1;
     }      }
       if (! exists($groupids_by_studentid{$student_id})) {
     foreach my $name (keys(%classlist)) {          &populate_students_groups_table();
         if(defined($c) && ($c->aborted())) {          undef(%groupids_by_studentid);
             $classlist{'error'}='aborted';          my @Result = &Apache::lonmysql::get_rows($students_groups_table);
             return \%classlist;          foreach (@Result) {
               push(@{$groupids_by_studentid{$_->[0]}},$_->[1]);
         }          }
       }
         my ($studentName,$studentDomain) = split(/\:/,$name);      if (exists($groupids_by_studentid{$student_id})) {
         # Download student environment data, specifically the full name and id.          if (ref($groupids_by_studentid{$student_id}) eq 'ARRAY') {
         my %studentInformation=&Apache::lonnet::get('environment',              return @{$groupids_by_studentid{$student_id}};
                                                     ['lastname','generation',  
                                                      'firstname','middlename',  
                                                      'id'],  
                                                     $studentDomain,  
                                                     $studentName);  
         $classlist{$name.':studentInformation'}=\%studentInformation;  
   
         if($c->aborted()) {  
             $classlist{'error'}='aborted';  
             return \%classlist;  
         }          }
   
         #Section  
         my %section=&Apache::lonnet::dump('roles',$studentDomain,$studentName);  
         $classlist{$name.':sections'}=\%section;  
     }      }
       return undef; # error
   }
   
     $classlist{'UpToDate'} = 'false';  
     $classlist{'lastDownloadTime'}=time;  
   
     return \%classlist;  sub populate_students_groups_table {
       my ($courseid) = @_;
       if (! defined($courseid)) {
           $courseid = $env{'request.course.id'};
       }
       #
       &setup_table_names($courseid);
       &init_dbs($courseid,0);
       my $dbh = &Apache::lonmysql::get_dbh();
       my $request = 'INSERT IGNORE INTO '.$students_groups_table.
           "(student_id,group_id) VALUES ";
       my $cdom = $env{'course.'.$courseid.'.domain'};
       my $cnum = $env{'course.'.$courseid.'.num'};
       my ($classlist,$keylist) = &get_classlist($cdom,$cnum);
       my ($classgroups,$studentgroups) = &get_group_memberships($classlist,
                                                                 $keylist,
                                                                 $cdom,$cnum);
       my $record_count = 0;
       foreach my $student (sort(keys(%{$classgroups}))) {
           my $student_id = &get_student_id(split(':',$student));
           my @studentsgroups = &get_students_groups($student,'Active',$classgroups);
           if (@studentsgroups < 1) {
               @studentsgroups = ('none');
           }
           foreach my $groupname (@studentsgroups) {
               my $group_id = &get_group_id($groupname);
               $request .= "('".$student_id."','".$group_id."'),";
               $record_count++;
           }
       }
       return if ($record_count == 0);
       chop($request);
       $dbh->do($request);
       if ($dbh->err()) {
           &Apache::lonnet::logthis("error ".$dbh->errstr().
                                    " occurred executing \n".
                                    $request);
       }
       return;
 }  }
   
 =pod  sub clear_internal_caches {
       $have_read_part_table = 0;
       undef(%ids_by_part);
       undef(%parts_by_id);
       $have_read_symb_table = 0;
       undef(%ids_by_symb);
       undef(%symbs_by_id);
       $have_read_student_table = 0;
       undef(%ids_by_student);
       undef(%students_by_id);
       $have_read_groupnames_table = 0;
       undef(%ids_by_groupname);
   }
   
 =item &DownloadCourseInformation()  sub symb_is_for_task {
       my ($symb) = @_;
       return ($symb =~ /\.task$/);
   }
   
 Dump of all the course information for a single student.  The data can be  
 pruned by making use of dumps regular expression arguement.  This function  
 also takes a regular expression which it passes straight through to dump.    
 The data is no escaped, because it is done elsewhere.  It also  
 checks the timestamp of the students course database file and only downloads  
 if it has been modified since the last download.  
   
 =over 4  sub update_full_student_data {
       my ($sname,$sdom,$courseid) = @_;
       #
       # Set up database names
       &setup_table_names($courseid);
       #
       my $student_id = &get_student_id($sname,$sdom);
       my $student = $sname.':'.$sdom;
       #
       my $returnstatus = 'okay';
       #
       # Download students data
       my $time_of_retrieval = time;
       my @tmp = &Apache::lonnet::dumpstore($courseid,$sdom,$sname);
       if (@tmp && $tmp[0] =~ /^error/) {
           $returnstatus = 'error retrieving full student data';
           return $returnstatus;
       } elsif (! @tmp) {
           $returnstatus = 'okay: no student data';
           return $returnstatus;
       }
       my %studentdata = @tmp;
       #
       # Get database handle and clean out the tables 
       my $dbh = &Apache::lonmysql::get_dbh();
       $dbh->do('DELETE FROM '.$fulldump_response_table.' WHERE student_id='.
                $student_id);
       $dbh->do('DELETE FROM '.$fulldump_part_table.' WHERE student_id='.
                $student_id);
       $dbh->do('DELETE FROM '.$fulldump_timestamp_table.' WHERE student_id='.
                $student_id);
       #
       # Parse and store the data into a form we can handle
       my $partdata;
       my $respdata;
       while (my ($key,$value) = each(%studentdata)) {
           next if ($key =~ /^(\d+):(resource$|subnum$|keys:)/);
           my ($transaction,$symb,$parameter) = split(':',$key);
    $symb = &unescape($symb);
    $parameter = &unescape($parameter);
           my $symb_id = &get_symb_id($symb);
           if ($parameter eq 'timestamp') {
               # We can deal with 'timestamp' right away
               my @timestamp_storage = ($symb_id,$student_id,
                                        $transaction,$value);
               my $store_command = 'INSERT IGNORE INTO '.$fulldump_timestamp_table.
                   " VALUES ('".join("','",@timestamp_storage)."');";
               $dbh->do($store_command);
               if ($dbh->err()) {
                   &Apache::lonnet::logthis('unable to execute '.$store_command);
                   &Apache::lonnet::logthis($dbh->errstr());
               }
               next;
           } elsif ($parameter eq 'version') {
               next;
    } elsif (&symb_is_for_task($symb)) {
       next if ($parameter !~ /^resource\.(.*)\.(award|
         awarded|
         solved|
         submission|
         portfiles|
         status|
         version|
         regrader)\s*$/x);
       my ($version_and_part_id, $field) = ($1,$2);
   
       next if ($version_and_part_id !~ /\./ 
        && $field ne 'regrader' && $field ne 'version');
   
       my ($version, $part, $instance) = 
    split(/\./,$version_and_part_id);
   
       #skip and instance dimension or criteria specific data
       next if (defined($instance) 
        && $instance ne $field
        && $instance ne 'bridgetask');
       
       if (!defined($part)) {
    $part = $version;
       }
       my $resp_id = &get_part_id('0');
       my $part_id = &get_part_id($part);
       
       if ($field eq 'version') {
    # for tasks each version is an attempt at it thus
    #     version -> tries
    $partdata->{$symb_id}{$part_id}{$transaction}{'tries'}=
       $value;
    # at new version time the record gets reset thus adding a
    # virtual response awarddetail of 'new_version'
    $respdata->{$symb_id}{$part_id}{$resp_id}{$transaction}{'response_specific'}='status';
    $respdata->{$symb_id}{$part_id}{$resp_id}{$transaction}{'response_specific_value'}='new_version';
   
       } elsif ($field eq 'award' || $field eq 'awarded' 
        || $field eq 'solved') {
    $partdata->{$symb_id}{$part_id}{$transaction}{$field}=
       $value;
       } elsif ($field eq 'portfiles') {
    # tasks only accepts portfolio submissions
    $value = $dbh->quote($value);
    $respdata->{$symb_id}{$part_id}{$resp_id}{$transaction}{'submission'}=$value;
       } elsif ($field eq 'status') {
    $respdata->{$symb_id}{$part_id}{$resp_id}{$transaction}{'response_specific'}=$field;
    $respdata->{$symb_id}{$part_id}{$resp_id}{$transaction}{'response_specific_value'}=$value;
       } elsif ($field eq 'regrader') {
    $respdata->{$symb_id}{$part_id}{$resp_id}{$transaction}{'response_specific_2'}=$field;
    $respdata->{$symb_id}{$part_id}{$resp_id}{$transaction}{'response_specific_value_2'}=$value;
       }
    } elsif ($parameter =~ /^resource\.(.*)\.(tries|
                                                     award|
                                                     awarded|
                                                     previous|
                                                     solved|
                                                     awarddetail|
                                                     submission|
                                                     submissiongrading|
                                                     molecule)\s*$/x){
               # we do not have enough information to store an 
               # entire row, so we save it up until later.
               my ($part_and_resp_id,$field) = ($1,$2);
               my ($part,$part_id,$resp,$resp_id);
               if ($part_and_resp_id =~ /\./) {
                   ($part,$resp) = split(/\./,$part_and_resp_id);
                   $part_id = &get_part_id($part);
                   $resp_id = &get_part_id($resp);
               } else {
                   $part_id = &get_part_id($part_and_resp_id);
               }
               # Deal with part specific data
               if ($field =~ /^(tries|award|awarded|previous)$/) {
                   $partdata->{$symb_id}->{$part_id}->{$transaction}->{$field}=$value;
               }
               # deal with response specific data
               if (defined($resp_id) &&
                   $field =~ /^(awarddetail|
                                submission|
                                submissiongrading|
                                molecule)$/x) {
                   if ($field eq 'submission') {
                       # We have to be careful with user supplied input.
                       # most of the time we are okay because it is escaped.
                       # However, there is one wrinkle: submissions which end in
                       # and odd number of '\' cause insert errors to occur.  
                       # Best trap this somehow...
                       $value = $dbh->quote($value);
                   }
                   if ($field eq 'submissiongrading' || 
                       $field eq 'molecule') {
                       $respdata->{$symb_id}->{$part_id}->{$resp_id}->{$transaction}->{'response_specific'}=$field;
                       $respdata->{$symb_id}->{$part_id}->{$resp_id}->{$transaction}->{'response_specific_value'}=$value;
                   } else {
                       $respdata->{$symb_id}->{$part_id}->{$resp_id}->{$transaction}->{$field}=$value;
                   }
               }
           }
       }
       ##
       ## Store the part data
       my $store_command = 'INSERT IGNORE INTO '.$fulldump_part_table.
           ' VALUES '."\n";
       my $store_rows = 0;
       while (my ($symb_id,$hash1) = each (%$partdata)) {
           while (my ($part_id,$hash2) = each (%$hash1)) {
               while (my ($transaction,$data) = each (%$hash2)) {
                   $store_command .= "('".join("','",$symb_id,$part_id,
                                               $student_id,
                                               $transaction,
                                               $data->{'tries'},
                                               $data->{'award'},
                                               $data->{'awarded'},
                                               $data->{'previous'})."'),";
                   $store_rows++;
               }
           }
       }
       if ($store_rows) {
           chop($store_command);
           $dbh->do($store_command);
           if ($dbh->err) {
               $returnstatus = 'error saving part data';
               &Apache::lonnet::logthis('insert error '.$dbh->errstr());
               &Apache::lonnet::logthis("While attempting\n".$store_command);
           }
       }
       ##
       ## Store the response data
       $store_command = 'INSERT IGNORE INTO '.$fulldump_response_table.
           ' VALUES '."\n";
       $store_rows = 0;
       while (my ($symb_id,$hash1) = each (%$respdata)) {
           while (my ($part_id,$hash2) = each (%$hash1)) {
               while (my ($resp_id,$hash3) = each (%$hash2)) {
                   while (my ($transaction,$data) = each (%$hash3)) {
                       my $submission = $data->{'submission'};
                       # We have to be careful with user supplied input.
                       # most of the time we are okay because it is escaped.
                       # However, there is one wrinkle: submissions which end in
                       # and odd number of '\' cause insert errors to occur.  
                       # Best trap this somehow...
                       $submission = $dbh->quote($submission);
                       $store_command .= "('".
                           join("','",$symb_id,$part_id,
                                $resp_id,$student_id,
                                $transaction,
                                $data->{'awarddetail'},
                                $data->{'response_specific'},
                                $data->{'response_specific_value'},
                                $data->{'response_specific_2'},
                                $data->{'response_specific_value_2'}).
                                "',".$submission."),";
                       $store_rows++;
                   }
               }
           }
       }
       if ($store_rows) {
           chop($store_command);
           $dbh->do($store_command);
           if ($dbh->err) {
               $returnstatus = 'error saving response data';
               &Apache::lonnet::logthis('insert error '.$dbh->errstr());
               &Apache::lonnet::logthis("While attempting\n".$store_command);
           }
       }
       ##
       ## Update the students "current" data in the performance 
       ## and parameters tables.
       my ($status,undef) = &store_student_data
           ($sname,$sdom,$courseid,
            &Apache::lonnet::convert_dump_to_currentdump(\%studentdata));
       if ($returnstatus eq 'okay' && $status ne 'okay') {
           $returnstatus = 'error saving current data:'.$status;
       } elsif ($status ne 'okay') {
           $returnstatus .= ' error saving current data:'.$status;
       }        
       ##
       ## Update the students time......
       if ($returnstatus eq 'okay') {
           &store_updatetime($student_id,$time_of_retrieval,$time_of_retrieval);
           if ($dbh->err) {
               if ($returnstatus eq 'okay') {
                   $returnstatus = 'error updating student time';
               } else {
                   $returnstatus = 'error updating student time';
               }
           }
       }
       return $returnstatus;
   }
   
 Input: $namedata, $courseID, $lastDownloadTime, $WhatIWant  
   
 $namedata: student name:domain  sub update_student_data {
       my ($sname,$sdom,$courseid) = @_;
       #
       # Set up database names
       &setup_table_names($courseid);
       #
       my $student_id = &get_student_id($sname,$sdom);
       my $student = $sname.':'.$sdom;
       #
       my $returnstatus = 'okay';
       #
       # Download students data
       my $time_of_retrieval = time;
       my %student_data = &Apache::lonnet::currentdump($courseid,$sdom,$sname);
       if (&Apache::lonnet::error(%student_data)) {
           &Apache::lonnet::logthis('error getting data for '.
                                    $sname.':'.$sdom.' in course '.$courseid.
                                    ':'.(%student_data)[0]);
           $returnstatus =(%student_data)[0] ;
           return ($returnstatus,undef);
       }
       if (scalar(keys(%student_data)) < 1) {
           return ('no data',undef);
       }
       my @Results = &store_student_data($sname,$sdom,$courseid,\%student_data);
       #
       # Set the students update time
       if ($Results[0] eq 'okay') {
           &store_updatetime($student_id,$time_of_retrieval);
       }
       #
       return @Results;
   }
   
 $courseID:  The id of the course  sub store_updatetime {
       my ($student_id,$updatetime,$fullupdatetime)=@_;
       my $values = '';
       if (defined($updatetime)) {
           $values = 'updatetime='.$updatetime.' ';
       }
       if (defined($fullupdatetime)) {
           if ($values ne '') {
               $values .= ',';
           }
           $values .= 'fullupdatetime='.$fullupdatetime.' ';
       }
       return if ($values eq '');
       my $dbh = &Apache::lonmysql::get_dbh();
       my $request = 'UPDATE '.$student_table.' SET '.$values.
           ' WHERE student_id='.$student_id.' LIMIT 1';
       $dbh->do($request);
   }
   
 $lastDownloadTime:  This is the date stamp for when this information was  my $requested_max_packet = 0;
 last gathered.  If it is set to Not downloaded, it will gather the data  my $max_allowed_packet;
 again, though it currently does not remove the old data.  
   
 $WhatIWant:  Regular expression used to get selected data with dump  sub store_student_data {
       my ($sname,$sdom,$courseid,$student_data) = @_;
       #
       my $student_id = &get_student_id($sname,$sdom);
       my $student = $sname.':'.$sdom;
       #
       my $returnstatus = 'okay';
       #
       # Remove all of the students data from the table
       my $dbh = &Apache::lonmysql::get_dbh();
       $dbh->do('DELETE FROM '.$performance_table.' WHERE student_id='.
                $student_id);
       $dbh->do('DELETE FROM '.$parameters_table.' WHERE student_id='.
                $student_id);
       #
       # Store away the data
       #
       my $starttime = Time::HiRes::time;
       my $elapsed = 0;
       my $rows_stored;
       my $store_parameters_prefix  = 'INSERT IGNORE INTO '.$parameters_table.
           ' VALUES '."\n";
       my $num_parameters = 0;
       my $store_performance_prefix = 'INSERT IGNORE INTO '.$performance_table.
           ' VALUES '."\n";
       return ('error',undef) if (! defined($dbh));
       unless ($requested_max_packet) {
           (undef,$max_allowed_packet) = $dbh->selectrow_array(
                                                qq{show variables LIKE ? },
                                                undef,
                                                "max_allowed_packet");
           if ($max_allowed_packet !~ /^\d+$/) {
               $max_allowed_packet = '';
           }
           $requested_max_packet = 1;
       }
       my @store_parameters_values = ();
       my $curr_params_values = '';
       my $curr_params_length = 0;
       my @store_performance_values = ();
       my $curr_perf_values = '';
       my $curr_perf_length = 0;
       my ($max_param,$max_perf);
       if ($max_allowed_packet) {
           $max_param = $max_allowed_packet - length($store_parameters_prefix);
           $max_perf = $max_allowed_packet - length($store_performance_prefix);
       }
       while (my ($current_symb,$param_hash) = each(%{$student_data})) {
           #
           # make sure the symb is set up properly
           my $symb_id = &get_symb_id($current_symb);
           #
           # Parameters
           while (my ($parameter,$value) = each(%$param_hash)) {
               if ($parameter !~ /(timestamp|resource\.(.*)\.(solved|tries|awarded|award|awarddetail|previous))/) {
                   my $sql_parameter = "('".join("','",
                                                 $symb_id,$student_id,
                                                 $parameter)."',".
                                                     $dbh->quote($value)."),\n";
                   if ($sql_parameter !~ /''/) {
                       if ($max_param) {
                           my $length = length($sql_parameter);
                           if ($length > $max_param) {
                               &Apache::lonnet::logthis("SQL parameter insert for student: $sname for parameter: $parameter would exceed max_allowed_packet size");
                               &Apache::lonnet::logthis("symb_id: $symb_id");
                               &Apache::lonnet::logthis("Skipping this item.  You may want to increase the max_allowed_packet size from the current: $max_allowed_packet");
                               next;
                           } else {
                               if ($length + $curr_params_length > $max_param) {
                                   push(@store_parameters_values,$curr_params_values);
                                   $curr_params_values = $sql_parameter;
                                   $curr_params_length = $length;
                               } else {
                                   $curr_params_values .= $sql_parameter;
                                   $curr_params_length += $length;
                               }
                           }
                       } else {
                           $curr_params_values .= $sql_parameter;
                       }
                       #$rows_stored++;
                       $num_parameters ++;
                   }
               }
           }
           # Performance
           my %stored;
           while (my ($parameter,$value) = each(%$param_hash)) {
               next if ($parameter !~ /^resource\.(.*)\.(solved|awarded)$/);
               my $part  = $1;
       my $which = $2;
       next if ($part =~ /\./);
               next if (exists($stored{$part}));
               $stored{$part}++;
               #
               my $part_id = &get_part_id($part);
               next if (!defined($part_id));
       
               my ($solved,$awarded);
       if ($which eq 'solved') {
    $solved  = $value;
    $awarded = $param_hash->{'resource.'.$part.'.awarded'};
       } else {
    $solved  = $param_hash->{'resource.'.$part.'.solved'};
    $awarded = $value;
       }
               my $award   = $param_hash->{'resource.'.$part.'.award'};
               my $awarddetail = $param_hash->{'resource.'.$part.'.awarddetail'};
               my $timestamp = $param_hash->{'timestamp'};
       my $tries   = $param_hash->{'resource.'.$part.'.tries'};
       if (&symb_is_for_task($current_symb)) {
    $tries   = $param_hash->{'resource.'.$part.'.version'};
       }
               #
               $solved      = '' if (! defined($solved));
               $tries       = '' if (! defined($tries));
               $awarded     = '' if (! defined($awarded));
               $award       = '' if (! defined($award));
               $awarddetail = '' if (! defined($awarddetail));
               my $sql_performance = 
                   "('".join("','",$symb_id,$student_id,$part_id,$part,
                                   $solved,$tries,$awarded,$award,
                                   $awarddetail,$timestamp)."'),\n";
               if ($max_perf) {
                   my $length = length($sql_performance);
                   if ($length > $max_perf) {
                               &Apache::lonnet::logthis("SQL performance insert for student: $sname would exceed max_allowed_packet size");
                               &Apache::lonnet::logthis("symb_id: $symb_id");
                               &Apache::lonnet::logthis("Skipping this item.  You may want to increase the max_allowed_packet size from the current: $max_allowed_packet");
                               next;
                   } else {
                       if ($length + $curr_perf_length > $max_perf) {
                           push(@store_performance_values,$curr_perf_values);
                           $curr_perf_values = $sql_performance;
                           $curr_perf_length = $length;
                       } else {
                           $curr_perf_values .= $sql_performance;
                           $curr_perf_length += $length;
                       }
                   }
               } else {
                   $curr_perf_values .= $sql_performance;
               }
               $rows_stored++;
           }
       }
       if ($curr_params_values ne '') {
           push(@store_parameters_values,$curr_params_values);
       }
       if ($curr_perf_values ne '') {
           push(@store_performance_values,$curr_perf_values);
       }
       if (! $rows_stored) { return ($returnstatus, undef); }
       my $start = Time::HiRes::time;
       foreach my $item (@store_performance_values) {
           $item =~ s|,\n$||;
           if ($item ne '') {
               $dbh->do($store_performance_prefix.$item);
               if ($dbh->err()) {
                   &Apache::lonnet::logthis('performance insert error:'.
                                            $dbh->errstr());
                   &Apache::lonnet::logthis('command = '.$/.$store_performance_prefix.$item);
                   $returnstatus = 'error: unable to insert performance into database';
                   return ($returnstatus,$student_data);
               }
           }
       }
       if ($num_parameters > 0) {
           foreach my $item (@store_parameters_values) {
               $item =~ s|,\n$||;
               if ($item ne '') {
                   $dbh->do($store_parameters_prefix.$item);
                   if ($dbh->err()) {
                        &Apache::lonnet::logthis('parameters insert error:'.
                                                 $dbh->errstr());
                        &Apache::lonnet::logthis('command = '.$/.$store_parameters_prefix.$item);
                        &Apache::lonnet::logthis('rows_stored = '.$rows_stored);
                        &Apache::lonnet::logthis('student_id = '.$student_id);
                        $returnstatus = 'error: unable to insert parameters into database';
                        return ($returnstatus,$student_data);
                   }
               }
           }
       }
       $elapsed += Time::HiRes::time - $start;
       return ($returnstatus,$student_data);
   }
   
 Output: \%courseData  
   
 \%courseData:  A hash pointer to the raw data from the students course  sub ensure_tables_are_set_up {
 database.      my ($courseid) = @_;
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       # 
       # Clean out package variables
       &setup_table_names($courseid);
       #
       # if the tables do not exist, make them
       my @CurrentTable = &Apache::lonmysql::tables_in_db();
       my ($found_symb,$found_student,$found_groups,$found_groupnames,$found_part,
           $found_performance,$found_parameters,$found_fulldump_part,
           $found_fulldump_response,$found_fulldump_timestamp,
           $found_weight);
       foreach (@CurrentTable) {
           $found_symb        = 1 if ($_ eq $symb_table);
           $found_student     = 1 if ($_ eq $student_table);
           $found_groups      = 1 if ($_ eq $students_groups_table);
           $found_groupnames  = 1 if ($_ eq $groupnames_table);
           $found_part        = 1 if ($_ eq $part_table);
           $found_performance = 1 if ($_ eq $performance_table);
           $found_parameters  = 1 if ($_ eq $parameters_table);
           $found_fulldump_part      = 1 if ($_ eq $fulldump_part_table);
           $found_fulldump_response  = 1 if ($_ eq $fulldump_response_table);
           $found_fulldump_timestamp = 1 if ($_ eq $fulldump_timestamp_table);
           $found_weight      = 1 if ($_ eq $weight_table);
       }
       if (!$found_symb          || 
           !$found_student       || !$found_part              ||
           !$found_performance   || !$found_parameters        ||
           !$found_fulldump_part || !$found_fulldump_response ||
           !$found_fulldump_timestamp || !$found_weight ) {
           if (&init_dbs($courseid,1)) {
               return 'error';
           }
       }
   }
   
 =back  sub ensure_current_data {
       my ($sname,$sdom,$courseid) = @_;
       my $status = 'okay';   # return value
       #
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       &ensure_tables_are_set_up($courseid);
       #
       # Get the update time for the user
       my $updatetime = 0;
       my $getuserdir = 1;
       my $modifiedtime = &Apache::lonnet::GetFileTimestamp
           ($sdom,$sname,$courseid.'.db',$getuserdir);
       #
       if ($modifiedtime == -1) {
    return ('no data',undef);
       }
   
       my $student_id = &get_student_id($sname,$sdom);
       &get_students_groupids($student_id);
       my @Result = &Apache::lonmysql::get_rows($student_table,
                                                "student_id ='$student_id'");
       my $data = undef;
       if (@Result) {
           $updatetime = $Result[0]->[6];  # Ack!  This is dumb!
       }
       if ($modifiedtime > $updatetime) {
           ($status,$data) = &update_student_data($sname,$sdom,$courseid);
       }
       return ($status,$data);
   }
   
 =cut  
   
 sub DownloadCourseInformation {  sub ensure_current_full_data {
     my ($namedata,$courseID,$lastDownloadTime,$WhatIWant)=@_;      my ($sname,$sdom,$courseid) = @_;
     my %courseData;      my $status = 'okay';   # return value
     my ($name,$domain) = split(/\:/,$namedata);      #
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       &ensure_tables_are_set_up($courseid);
       #
       # Get the update time for the user
       my $getuserdir = 1;
       my $modifiedtime = &Apache::lonnet::GetFileTimestamp
           ($sdom,$sname,$courseid.'.db',$getuserdir);
       #
       my $student_id = &get_student_id($sname,$sdom);
       &get_students_groupids($student_id);
       my @Result = &Apache::lonmysql::get_rows($student_table,
                                                "student_id ='$student_id'");
       my $updatetime;
       if (@Result && ref($Result[0]) eq 'ARRAY') {
           $updatetime = $Result[0]->[7];
       }
       if (! defined($updatetime) || $modifiedtime > $updatetime) {
           $status = &update_full_student_data($sname,$sdom,$courseid);
       }
       return $status;
   }
   
     my $modifiedTime = &Apache::lonnet::GetFileTimestamp($domain, $name,  sub ensure_current_groups {
                                       $courseID.'.db',       my ($courseid) = @_;  
                                       $Apache::lonnet::perlvar{'lonUsersDir'});      my ($cdom,$cnum);
       if (defined($courseid)) {
           my %coursehash = &Apache::lonnet::coursedescription($courseid);
           $cdom = $coursehash{'domain'};
           $cnum = $coursehash{'num'};
       } elsif ($env{'request.course.id'}) {
           $courseid = $env{'request.course.id'};
           $cdom = $env{'course.'.$courseid.'.domain'};
           $cnum = $env{'course.'.$courseid.'.num'};
       }
       if ($cdom eq '' || $cnum eq '') {
           return 'error: invalid course';
       }
       &setup_table_names($courseid);
       my @CurrentTables = &Apache::lonmysql::tables_in_db();
       unless (grep(/^\Q$groupnames_table\E$/,@CurrentTables)) {
           return;
       }
       # Get the update time for the groupnames table
       my $getuserdir = 1;
       my $modifiedtime = &Apache::lonnet::GetFileTimestamp
           ($cdom,$cnum,'coursegroups.db',$getuserdir);
       my %tableinfo = &Apache::lonmysql::table_information($groupnames_table);
       my $updatetime;
       if ($tableinfo{'Update_time'}) {
           $updatetime = $tableinfo{'Update_time'};
       }
       if (! defined($updatetime) || $modifiedtime > $updatetime) {
           my (%groups_in_sql,%removegroups,$addgroup);
           my %curr_groups = &Apache::longroup::coursegroups($cdom,$cnum);
           my @Result = &Apache::lonmysql::get_rows($groupnames_table);
           foreach my $row (@Result) {
               my ($id,$name) = @{$row};
               unless (exists($curr_groups{$name})) {
                   $groups_in_sql{$name}=$id;
               } elsif ($id) {
                   $removegroups{$id} = $name;
               }
           }
           foreach my $group (keys(%curr_groups)) {
               unless (exists($groups_in_sql{$group})) {
                   $addgroup = 1;
                   last;
               }
           }
           if (keys(%removegroups)) {
               my $dbh = &Apache::lonmysql::get_dbh();
               foreach my $group_id (keys(%removegroups)) {
                   my $command = 'DELETE FROM '.$groupnames_table.' WHERE group_id='.
                                 $group_id;
                   $dbh->do($command);
                   if ($dbh->err()) {
                       &Apache::lonnet::logthis("error ".$dbh->errstr().
                                                " occurred executing \n".
                                                "SQL command: $command");
                   }
               }
           }
           if ($addgroup) {
               &populate_groupnames_table($courseid);
           }
       }
       return;
   }
   
     if($lastDownloadTime >= $modifiedTime && $modifiedTime >= 0) {  sub ensure_current_students_groups {
         # Data is not gathered so return UpToDate as true.  This      my ($courseid) = @_;
         # will be interpreted in ProcessClasslist      my ($cdom,$cnum);
         $courseData{$namedata.':lastDownloadTime'}=time;      if (defined($courseid)) {
         $courseData{$namedata.':UpToDate'} = 'true';          my %coursehash = &Apache::lonnet::coursedescription($courseid);
         return \%courseData;          $cdom = $coursehash{'domain'};
           $cnum = $coursehash{'num'};
       } elsif ($env{'request.course.id'}) {
           $courseid = $env{'request.course.id'};
           $cdom = $env{'course.'.$courseid.'.domain'};
           $cnum = $env{'course.'.$courseid.'.num'};
       }
       &setup_table_names($courseid);
       my @CurrentTables = &Apache::lonmysql::tables_in_db();
       unless (grep(/^\Q$students_groups_table\E$/,@CurrentTables)) {
           return;
       }
       # Get the update time for the groupnames table
       my $getuserdir = 1;
       my $modifiedtime = &Apache::lonnet::GetFileTimestamp
           ($cdom,$cnum,'groupmembership.db',$getuserdir);
       my %tableinfo = &Apache::lonmysql::table_information($students_groups_table);
       my $updatetime;
       if ($tableinfo{'Update_time'}) {
           $updatetime = $tableinfo{'Update_time'};
       }
       if ((!defined($updatetime)) || ($modifiedtime > $updatetime)) {
           if (&Apache::lonmysql::drop_table($students_groups_table)) {
               if (&init_dbs($courseid)) {
                   return "error creating $students_groups_table\n";
               } else {
                   &populate_students_groups_table($courseid);
               }
           }
     }      }
       return;
   }
   
     # Download course data  sub ensure_current_sections {
     if(!defined($WhatIWant)) {      my ($courseid) = @_;
         # set the regular expression to everything by setting it to period      my ($cdom,$cnum);
         $WhatIWant = '.';      if (defined($courseid)) {
           my %coursehash = &Apache::lonnet::coursedescription($courseid);
           $cdom = $coursehash{'domain'};
           $cnum = $coursehash{'num'};
       } elsif ($env{'request.course.id'}) {
           $courseid = $env{'request.course.id'};
           $cdom = $env{'course.'.$courseid.'.domain'};
           $cnum = $env{'course.'.$courseid.'.num'};
       }
       &setup_table_names($courseid);
       my @CurrentTables = &Apache::lonmysql::tables_in_db();
       unless (grep(/^\Q$student_table\E$/,@CurrentTables)) {
           return;
     }      }
     %courseData=&Apache::lonnet::dump($courseID, $domain, $name, $WhatIWant);      # Get the update time for the student table
     $courseData{'UpToDate'} = 'false';      my $getuserdir = 1;
     $courseData{'lastDownloadTime'}=time;      my $modifiedtime = &Apache::lonnet::GetFileTimestamp
           ($cdom,$cnum,'classlist.db',$getuserdir);
       my %tableinfo = &Apache::lonmysql::table_information($student_table);
       my $updatetime;
       if ($tableinfo{'Update_time'}) {
           $updatetime = $tableinfo{'Update_time'};
       }
       if ((!defined($updatetime)) || ($modifiedtime > $updatetime)) {
           &update_student_table($cdom,$cnum);
       }
       return;
   }
   
     my %newData;  sub update_student_table {
     foreach (keys(%courseData)) {      my ($cdom,$cnum) = @_;
         # need to have the keys to be prepended with the name:domain of the      return unless (($cdom ne '') && ($cnum ne ''));
         # student to reduce data collision later.      my (%roster,%sqldata);
         $newData{$namedata.':'.$_} = $courseData{$_};      my $classlist = &get_classlist($cdom,$cnum);
       while (my ($student,$data) = each (%$classlist)) {
           my ($section,$start,$end) = ($data->[&CL_SECTION()],
                                        $data->[&CL_START()],
                                        $data->[&CL_END()]);
           if ($section eq '' || $section =~ /^\s*$/) {
               $section = 'none';
           }
           if ($start eq '') { $start = 0; }
           if ($end eq '')   { $end   = 0; }
           $roster{$student}{'section'} = $section;
           $roster{$student}{'start'} = $start;
           $roster{$student}{'end'} = $end;
       }
       my $dbh = &Apache::lonmysql::get_dbh();
       my $statement = "SELECT student_id,student,section,start,end FROM $student_table";
       my $sth = $dbh->prepare($statement);
       $sth->execute();
       if ($sth->err()) {
           &Apache::lonnet::logthis("Unable to execute MySQL request:");
           &Apache::lonnet::logthis("\n".$statement."\n");
           &Apache::lonnet::logthis("error is:".$sth->errstr());
           return undef;
       }
       foreach my $row (@{$sth->fetchall_arrayref}) {
           my ($id,$student,$section,$start,$end) = (@$row);
           if (ref($roster{$student}) eq 'HASH') {
               if (($roster{$student}{'section'} ne $section) ||
                   ($roster{$student}{'start'} ne $start) ||
                   ($roster{$student}{'end'} ne $end)) {
                   $sqldata{$id} = {
                                     section => $roster{$student}{'section'},
                                     start   => $roster{$student}{'start'},
                                     end     => $roster{$student}{'end'},
                                   };
               }
           }
     }      }
       $sth->finish();
       if (keys(%sqldata)) { 
           foreach my $id (sort { $a <=> $b } keys(%sqldata)) {
               my $request = "UPDATE $student_table SET section='$sqldata{$id}{section}'".
                             ", start='$sqldata{$id}{start}'".
                             ", end='$sqldata{$id}{end}' WHERE student_id='$id'";
               $dbh->do($request);
           }
       }
       return;
   }
   
     return \%newData;  sub get_student_data_from_performance_cache {
       my ($sname,$sdom,$symb,$courseid)=@_;
       my $student = $sname.':'.$sdom if (defined($sname) && defined($sdom));
       &setup_table_names($courseid);
       #
       # Return hash
       my $studentdata;
       #
       my $dbh = &Apache::lonmysql::get_dbh();
       my $request = "SELECT ".
           "d.symb,a.part,a.solved,a.tries,a.awarded,a.award,a.awarddetail,".
               "a.timestamp ";
       if (defined($student)) {
           $request .= "FROM $student_table AS b ".
               "LEFT JOIN $performance_table AS a ON b.student_id=a.student_id ".
   #            "LEFT JOIN $part_table AS c ON c.part_id = a.part_id ".
               "LEFT JOIN $symb_table AS d ON d.symb_id = a.symb_id ".
                   "WHERE student='$student'";
           if (defined($symb) && $symb ne '') {
               $request .= " AND d.symb=".$dbh->quote($symb);
           }
       } elsif (defined($symb) && $symb ne '') {
           $request .= "FROM $symb_table as d ".
               "LEFT JOIN $performance_table AS a ON d.symb_id=a.symb_id ".
   #            "LEFT JOIN $part_table    AS c ON c.part_id = a.part_id ".
               "LEFT JOIN $student_table AS b ON b.student_id = a.student_id ".
                   "WHERE symb='".$dbh->quote($symb)."'";
       }
       my $starttime = Time::HiRes::time;
       my $rows_retrieved = 0;
       my $sth = $dbh->prepare($request);
       $sth->execute();
       if ($sth->err()) {
           &Apache::lonnet::logthis("Unable to execute MySQL request:");
           &Apache::lonnet::logthis("\n".$request."\n");
           &Apache::lonnet::logthis("error is:".$sth->errstr());
           return undef;
       }
       foreach my $row (@{$sth->fetchall_arrayref}) {
           $rows_retrieved++;
           my ($symb,$part,$solved,$tries,$awarded,$award,$awarddetail,$time) = 
               (@$row);
           my $base = 'resource.'.$part;
           $studentdata->{$symb}->{$base.'.solved'}  = $solved;
           $studentdata->{$symb}->{$base.'.tries'}   = $tries;
           $studentdata->{$symb}->{$base.'.awarded'} = $awarded;
           $studentdata->{$symb}->{$base.'.award'}   = $award;
           $studentdata->{$symb}->{$base.'.awarddetail'} = $awarddetail;
           $studentdata->{$symb}->{'timestamp'} = $time if (defined($time) && $time ne '');
       }
       ## Get misc parameters
       $request = 'SELECT c.symb,a.parameter,a.value '.
           "FROM $student_table AS b ".
           "LEFT JOIN $parameters_table AS a ON b.student_id=a.student_id ".
           "LEFT JOIN $symb_table AS c ON c.symb_id = a.symb_id ".
           "WHERE student='$student'";
       if (defined($symb) && $symb ne '') {
           $request .= " AND c.symb=".$dbh->quote($symb);
       }
       $sth = $dbh->prepare($request);
       $sth->execute();
       if ($sth->err()) {
           &Apache::lonnet::logthis("Unable to execute MySQL request:");
           &Apache::lonnet::logthis("\n".$request."\n");
           &Apache::lonnet::logthis("error is:".$sth->errstr());
           if (defined($symb) && $symb ne '') {
               $studentdata = $studentdata->{$symb};
           }
           return $studentdata;
       }
       #
       foreach my $row (@{$sth->fetchall_arrayref}) {
           $rows_retrieved++;
           my ($symb,$parameter,$value) = (@$row);
           $studentdata->{$symb}->{$parameter}  = $value;
       }
       #
       if (defined($symb) && $symb ne '') {
           $studentdata = $studentdata->{$symb};
       }
       return $studentdata;
 }  }
   
 # ----- END DOWNLOAD INFORMATION ---------------------------------------  
   
 =pod  sub get_current_state {
       my ($sname,$sdom,$symb,$courseid,$forcedownload)=@_;
       #
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       #
       return () if (! defined($sname) || ! defined($sdom));
       #
       my ($status,$data) = &ensure_current_data($sname,$sdom,$courseid);
   #    &Apache::lonnet::logthis
   #        ('sname = '.$sname.
   #         ' domain = '.$sdom.
   #         ' status = '.$status.
   #         ' data is '.(defined($data)?'defined':'undefined'));
   #    while (my ($symb,$hash) = each(%$data)) {
   #        &Apache::lonnet::logthis($symb."\n----------------------------------");
   #        while (my ($key,$value) = each (%$hash)) {
   #            &Apache::lonnet::logthis("   ".$key." = ".$value);
   #        }
   #    }
       #
       if (defined($data) && defined($symb) && ref($data->{$symb})) {
           return %{$data->{$symb}};
       } elsif (defined($data) && ! defined($symb) && ref($data)) {
           return %$data;
       } 
       if ($status eq 'no data') {
           return ();
       } else {
           if ($status ne 'okay' && $status ne '') {
               &Apache::lonnet::logthis('status = '.$status);
               return ('error: '.$status,undef);
           }
           my $returnhash = &get_student_data_from_performance_cache($sname,$sdom,
                                                         $symb,$courseid);
           return %$returnhash if (defined($returnhash));
       }
       return ();
   }
   
 =head1 PROCESSING FUNCTIONS  
   
 These functions process all the data for all the students.  Also, they  sub get_problem_statistics {
 are the functions that access the cache database for writing the majority of      my ($Sections,$Groups,$status,$symb,$part,$courseid,$starttime,$endtime) = @_;
 the time.  The downloading and caching were separated to reduce problems       return if (! defined($symb) || ! defined($part));
 with stopping downloading then can not tie hash to database later.      $courseid = $env{'request.course.id'} if (! defined($courseid));
       #
       &setup_table_names($courseid);
       my $symb_id = &get_symb_id($symb);
       my $part_id = &get_part_id($part);
       my $stats_table = &temp_table_name($courseid,'problem_stats');
       #
       my $dbh = &Apache::lonmysql::get_dbh();
       return undef if (! defined($dbh));
       #
       # Clean out the table
       $dbh->do('DROP TABLE '.$stats_table);  # May return an error
       my $request = 
           'CREATE TEMPORARY TABLE '.$stats_table.' '.
           'SELECT a.student_id,a.solved,a.award,a.awarded,a.tries '.
           'FROM '.$performance_table.' AS a ';
       #
       # See if we need to include some requirements on the students
       if ((defined($Sections) && lc($Sections->[0]) ne 'all') || 
           (defined($status)   && lc($status)        ne 'any')) {
           $request .= 'NATURAL LEFT JOIN '.$student_table.' AS b ';
       }
       my ($groups_join,$group_limits) = &limit_by_group($Groups,'b','c','d');
       if (defined($groups_join)) {
           $request .= $groups_join;
       }
       $request .= ' WHERE a.symb_id='.$symb_id.' AND a.part_id='.$part_id;
       #
       # Limit the students included to those specified
       my ($section_limits,$enrollment_limits)=
           &limit_by_section_and_status($Sections,$status,'b');
       #
       # Limit by starttime and endtime
       my $time_requirements = undef;
       if (defined($starttime)) {
           $time_requirements .= 'a.timestamp>='.$starttime;
           if (defined($endtime)) {
               $time_requirements .= ' AND a.timestamp<='.$endtime;
           }
       } elsif (defined($endtime)) {
           $time_requirements .= 'a.timestamp<='.$endtime;
       }
       if (defined($time_requirements)) {
           $request .= ' AND '.$time_requirements;
       }
       if (defined($section_limits)) {
           $request .= ' AND '.$section_limits;
       }
       if (defined($enrollment_limits)) {
           $request .= ' AND '.$enrollment_limits;
       }
       # Limit by group, as required
       if (defined($group_limits)) {
           $request .= ' AND '.$group_limits;
       }
       #
       # Finally, execute the request to create the temporary table
       $dbh->do($request);
       #
       # Collect the first suite of statistics
       $request = 'SELECT COUNT(*),SUM(tries),'.
           'AVG(tries),STD(tries) '.
           'FROM '.$stats_table;
       my ($num,$tries,$mean,$STD) = &execute_SQL_request
           ($dbh,$request);
       #
       $request = 'SELECT MAX(tries),MIN(tries) FROM '.$stats_table.
           ' WHERE awarded>0';
       my ($max,$min) = &execute_SQL_request($dbh,$request);
       #
       $request = 'SELECT SUM(awarded) FROM '.$stats_table;
       my ($Solved) = &execute_SQL_request($dbh,$request);
       #
       $request = 'SELECT SUM(awarded) FROM '.$stats_table.
           " WHERE solved='correct_by_override'";
       my ($solved) = &execute_SQL_request($dbh,$request);
       #
       $Solved -= $solved;
       #
       $num    = 0 if (! defined($num));
       $tries  = 0 if (! defined($tries));
       $max    = 0 if (! defined($max));
       $min    = 0 if (! defined($min));
       $STD    = 0 if (! defined($STD));
       $Solved = 0 if (! defined($Solved) || $Solved < 0);
       $solved = 0 if (! defined($solved));
       #
       # Compute the more complicated statistics
       my $DegOfDiff = 'nan';
       $DegOfDiff = 1-($Solved)/$tries if ($tries>0);
       #
       my $SKEW = 'nan';
       my $wrongpercent = 0;
       my $numwrong = 'nan';
       if ($num > 0) {
           ($SKEW) = &execute_SQL_request($dbh,'SELECT SQRT(SUM('.
                                        'POWER(tries - '.$STD.',3)'.
                                        '))/'.$num.' FROM '.$stats_table);
           $numwrong = $num-$Solved;
           $wrongpercent=int(10*100*$numwrong/$num)/10;
       }
       #
       # Drop the temporary table
       $dbh->do('DROP TABLE '.$stats_table);  # May return an error
       #
       # Return result
       return { num_students => $num,
                tries        => $tries,
                max_tries    => $max,
                min_tries    => $min,
                mean_tries   => $mean,
                std_tries    => $STD,
                skew_tries   => $SKEW,
                num_solved   => $Solved,
                num_override => $solved,
                num_wrong    => $numwrong,
                per_wrong    => $wrongpercent,
                deg_of_diff  => $DegOfDiff };
   }
   
 =cut  ##
   ## This is a helper for get_statistics
   sub execute_SQL_request {
       my ($dbh,$request)=@_;
   #    &Apache::lonnet::logthis($request);
       my $sth = $dbh->prepare($request);
       if (!$sth) {
    die($dbh->errstr . " SQL: $request");
       }
       $sth->execute();
       my $row = $sth->fetchrow_arrayref();
       if (ref($row) eq 'ARRAY' && scalar(@$row)>0) {
           return @$row;
       }
       return ();
   }
   
 # ----- PROCESSING FUNCTIONS ---------------------------------------  
   
 =pod  sub populate_weight_table {
       my ($courseid) = @_;
       if (! defined($courseid)) {
           $courseid = $env{'request.course.id'};
       }
       #
       &setup_table_names($courseid);
       my $navmap = Apache::lonnavmaps::navmap->new();
       if (!defined($navmap)) {
           &Apache::lonnet::logthis('loncoursedata::populate_weight_table:'.$/.
                                    '  unable to get navmaps resource'.$/.
                                    '  '.join(' ',(caller)));
           return;
       }
       my @sequences = $navmap->retrieveResources(undef,
                                                  sub { shift->is_map(); },1,0,1);
       my @resources;
       foreach my $seq (@sequences) {
           push(@resources,$navmap->retrieveResources($seq,
                                                      sub {shift->is_problem();},
                                                      0,0,0));
       }
       if (! scalar(@resources)) {
           &Apache::lonnet::logthis('loncoursedata::populate_weight_table:'.$/.
                                    ' no resources returned for '.$courseid);
           return;
       }
       #       Since we use lonnet::EXT to retrieve problem weights,
       #       to ensure current data we must clear the caches out.
       &Apache::lonnet::clear_EXT_cache_status();
       my $dbh = &Apache::lonmysql::get_dbh();
       my $request = 'INSERT IGNORE INTO '.$weight_table.
           "(symb_id,part_id,weight) VALUES ";
       my $weight;
       foreach my $res (@resources) {
           my $symb_id = &get_symb_id($res->symb);
           foreach my $part (@{$res->parts}) {
               my $part_id = &get_part_id($part);
               $weight = &Apache::lonnet::EXT('resource.'.$part.'.weight',
                                              $res->symb,
                                              undef,undef,undef);
               if (!defined($weight) || ($weight eq '')) { 
                   $weight=1;
               }
               $request .= "('".$symb_id."','".$part_id."','".$weight."'),";
           }
       }
       $request =~ s/(,)$//;
   #    &Apache::lonnet::logthis('request = '.$/.$request);
       $dbh->do($request);
       if ($dbh->err()) {
           &Apache::lonnet::logthis("error ".$dbh->errstr().
                                    " occurred executing \n".
                                    $request);
       }
       return;
   }
   
 =item &ProcessTopResourceMap()  sub limit_by_start_end_time {
       my ($starttime,$endtime,$table) = @_;
       my $time_requirements = undef;
       if (defined($starttime)) {
           $time_requirements .= $table.".timestamp>='".$starttime."'";
           if (defined($endtime)) {
               $time_requirements .= " AND ".$table.".timestamp<='".$endtime."'";
           }
       } elsif (defined($endtime)) {
           $time_requirements .= $table.".timestamp<='".$endtime."'";
       }
       return $time_requirements;
   }
   
 Trace through the "big hash" created in rat/lonuserstate.pm::loadmap.    
 Basically, this function organizes a subset of the data and stores it in  
 cached data.  The data stored is the problems, sequences, sequence titles,  
 parts of problems, and their ordering.  Column width information is also   
 partially handled here on a per sequence basis.  
   
 =over 4  sub limit_by_section_and_status {
       my ($Sections,$enrollment,$tablename) = @_;
       my $student_requirements = undef;
       if ( (defined($Sections) && $Sections->[0] ne 'all')) {
           $student_requirements = '('.
               join(' OR ', map { $tablename.".section='".$_."'" } @$Sections
                    ).')';
       }
       my $enrollment_requirements=undef;
       if (defined($enrollment) && $enrollment ne 'Any') {
    my $now = time();
    if ( $enrollment eq 'Future' ) {
       $enrollment_requirements = 
    "( $tablename.start > $now AND ".
    "( $tablename.end = 0 OR $tablename.end > $now))";
    } elsif ( $enrollment eq 'Active' ) {
       $enrollment_requirements = 
    "(( $tablename.start = 0 OR $tablename.start < $now )  AND ".
    " ( $tablename.end   = 0 OR $tablename.end   > $now ))";
    } elsif ( $enrollment eq 'Expired' ) {
       $enrollment_requirements = 
    "(( $tablename.start < $now )  AND ".
    " ( $tablename.end   < $now ))";
    }
       }
       return ($student_requirements,$enrollment_requirements);
   }
   
 Input: $cache, $c  
   
 $cache:  A pointer to a hash to store the information  
   
 $c:  The connection class used to determine if an abort has been sent to the   sub limit_by_group {
 browser      my ($Groups,$stutable,$grptable,$stugrptab) = @_;
       my $groups_join = undef;
       my $group_limits = undef;
       if ( (defined($Groups) && $Groups->[0] ne 'all')) {
           $groups_join =
             ' LEFT JOIN '.$students_groups_table.
                        ' AS '.$stugrptab.' ON '.
                        $stugrptab.'.student_id = '.$stutable.'.student_id'.
             ' LEFT JOIN '.$groupnames_table.
                        ' AS '.$grptable.' ON '.
                        $stugrptab.'.group_id = '.$grptable.'.group_id ';
           $group_limits =
             ' ('.
                join(' OR ', map {  "$grptable.groupname='".$_."'" } @$Groups
              ).')';
       }
       return ($groups_join,$group_limits);
   }
   
 Output: A string that contains an error message or "OK" if everything went   
 smoothly.  
   
 =back  sub RNK_student { return 0; };
   sub RNK_score   { return 1; };
   
 =cut  sub rank_students_by_scores_on_resources {
       my ($resources,$Sections,$Groups,$enrollment,$courseid,$starttime,$endtime,
           $has_award_for) = @_;
       return if (! defined($resources) || ! ref($resources) eq 'ARRAY');
       if (! defined($courseid)) {
           $courseid = $env{'request.course.id'};
       }
       #
       &setup_table_names($courseid);
       my $dbh = &Apache::lonmysql::get_dbh();
       my ($section_limits,$enrollment_limits)=
           &limit_by_section_and_status($Sections,$enrollment,'b');
       my ($groups_join,$group_limits) = &limit_by_group($Groups,'b','c','d');
       my $symb_limits = '('.join(' OR ',map {'a.symb_id='.&get_symb_id($_);
                                          } @$resources
                                  ).')';
       my ($award_col, $award_join, $award_clause) = ('', '', '');
       if ($has_award_for) {
           my $resource_id = &get_symb_id($has_award_for);
           $award_col = ", perf.awarded";
           $award_join = "LEFT JOIN $performance_table AS perf ON perf.symb_id"
               ." = $resource_id AND perf.student_id = b.student_id ";
           $award_clause = "AND perf.awarded IS NOT NULL";
       }
       my $time_limits = &limit_by_start_end_time($starttime,$endtime,'a');
       my $request = "SELECT b.student,SUM(a.awarded*w.weight) AS score "
           ."$award_col FROM $performance_table AS a ".
           "NATURAL LEFT JOIN $weight_table AS w ".
           "LEFT JOIN $student_table AS b ON a.student_id=b.student_id ".
           "$award_join $groups_join "; 
       my $limits;
       if (defined($section_limits)) {
           $limits .= $section_limits.' AND ';
       }
       if (defined($enrollment_limits)) {
           $limits .= $enrollment_limits.' AND ';
       }
       if (defined($time_limits)) {
           $limits .= $time_limits.' AND ';
       }
       if ($symb_limits ne '()') {
           $limits .= $symb_limits.' AND ';
       }
       if (defined($group_limits)) {
           $limits .= $group_limits.' AND ';
       }
       if ($limits) {
           $limits =~ s/( AND )$//;   # Remove extra conjunction
           $request .= "WHERE $limits";
       } 
       $request .= " $award_clause GROUP BY a.student_id ORDER BY score, b.student";
       #&Apache::lonnet::logthis('request = '.$/.$request);
       my $sth = $dbh->prepare($request) or die "Can't prepare $request";
       $sth->execute();
       my $rows = $sth->fetchall_arrayref();
       return ($rows);
   }
   
 sub ProcessTopResourceMap {  sub get_sum_of_scores {
     my ($cache,$c)=@_;      my ($symb,$part,$students,$courseid,$starttime,$endtime) = @_;
     my %hash;      if (! defined($courseid)) {
     my $fn=$ENV{'request.course.fn'};          $courseid = $env{'request.course.id'};
     if(-e "$fn.db") {      }
  my $tieTries=0;      if (defined($students) && 
  while($tieTries < 3) {          ((@$students == 0) ||
             if($c->aborted()) {           (@$students == 1 && (! defined($students->[0]) || 
                 return;                                $students->[0] eq ''))
             }           )
     if(tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640)) {          ){
  last;          undef($students);
     }      }
     $tieTries++;      #
     sleep 1;      &setup_table_names($courseid);
  }      my $dbh = &Apache::lonmysql::get_dbh();
  if($tieTries >= 3) {      my $time_limits = &limit_by_start_end_time($starttime,$endtime,'a');
             return 'Coursemap undefined.';      my $request = 'SELECT SUM(a.awarded*w.weight),SUM(w.weight) FROM '.
         }          $performance_table.' AS a '.
     } else {          'NATURAL LEFT JOIN '.$weight_table.' AS w ';
         return 'Can not open Coursemap.';      $request .= 'WHERE a.symb_id='.&get_symb_id($symb).
           ' AND a.part_id='.&get_part_id($part);
       if (defined($time_limits)) {
           $request .= ' AND '.$time_limits;
       }
       if (defined($students)) {
           $request .= ' AND ('.
               join(' OR ',map {'a.student_id='.&get_student_id(split(':',$_));
                            } @$students).
                                ')';
       }
       my $sth = $dbh->prepare($request);
       $sth->execute();
       my $rows = $sth->fetchrow_arrayref();
       if ($dbh->err) {
           &Apache::lonnet::logthis('error 1 = '.$dbh->errstr());
           &Apache::lonnet::logthis('prepared then executed, fetchrow_arrayrefed'.
                                    $/.$request);
           return (undef,undef);
     }      }
       return ($rows->[0],$rows->[1]);
   }
   
     my $oldkeys;  
     if(defined($cache->{'ResourceKeys'})) {  
         $oldkeys = $cache->{'ResourceKeys'};  
         foreach (split(':::', $cache->{'ResourceKeys'})) {  
             delete $cache->{$_};  
         }  
         delete $cache->{'ResourceKeys'};  
     }  
   
     # Initialize state machine.  Set information pointing to top level map.  
     my (@sequences, @currentResource, @finishResource);  
     my ($currentSequence, $currentResourceID, $lastResourceID);  
   
     $currentResourceID=$hash{'ids_'.  
       &Apache::lonnet::clutter($ENV{'request.course.uri'})};  
     push(@currentResource, $currentResourceID);  
     $lastResourceID=-1;  
     $currentSequence=-1;  
     my $topLevelSequenceNumber = $currentSequence;  
   
     my %sequenceRecord;  
     my %allkeys;  
     while(1) {  
         if($c->aborted()) {  
             last;  
         }  
  # HANDLE NEW SEQUENCE!  
  #if page || sequence  
  if(defined($hash{'map_pc_'.$hash{'src_'.$currentResourceID}}) &&  
            !defined($sequenceRecord{$currentResourceID})) {  
             $sequenceRecord{$currentResourceID}++;  
     push(@sequences, $currentSequence);  
     push(@currentResource, $currentResourceID);  
     push(@finishResource, $lastResourceID);  
   
     $currentSequence=$hash{'map_pc_'.$hash{'src_'.$currentResourceID}};  
   
             # Mark sequence as containing problems.  If it doesn't, then  
             # it will be removed when processing for this sequence is  
             # complete.  This allows the problems in a sequence  
             # to be outputed before problems in the subsequences  
             if(!defined($cache->{'orderedSequences'})) {  
                 $cache->{'orderedSequences'}=$currentSequence;  
             } else {  
                 $cache->{'orderedSequences'}.=':'.$currentSequence;  
             }  
             $allkeys{'orderedSequences'}++;  
   
     $lastResourceID=$hash{'map_finish_'.  sub score_stats {
   $hash{'src_'.$currentResourceID}};      my ($Sections,$Groups,$enrollment,$symbs,$starttime,$endtime,$courseid)=@_;
     $currentResourceID=$hash{'map_start_'.      if (! defined($courseid)) {
      $hash{'src_'.$currentResourceID}};          $courseid = $env{'request.course.id'};
       }
     if(!($currentResourceID) || !($lastResourceID)) {      #
  $currentSequence=pop(@sequences);      &setup_table_names($courseid);
  $currentResourceID=pop(@currentResource);      my $dbh = &Apache::lonmysql::get_dbh();
  $lastResourceID=pop(@finishResource);      #
  if($currentSequence eq $topLevelSequenceNumber) {      my ($section_limits,$enrollment_limits)=
     last;          &limit_by_section_and_status($Sections,$enrollment,'b');
  }      my ($groups_join,$group_limits) = &limit_by_group($Groups,'b','c','d');
     }      my $time_limits = &limit_by_start_end_time($starttime,$endtime,'a');
             next;      my @Symbids = map { &get_symb_id($_); } @{$symbs};
  }      #
       my $stats_table = &temp_table_name($courseid,'problem_stats');
       my $symb_restriction = join(' OR ',map {'a.symb_id='.$_;} @Symbids);
       my $request = 'DROP TABLE '.$stats_table;
       $dbh->do($request);
       $request = 
           'CREATE TEMPORARY TABLE '.$stats_table.' '.
           'SELECT a.student_id,'.
           'SUM(a.awarded*w.weight) AS score FROM '.
           $performance_table.' AS a '.
           'NATURAL LEFT JOIN '.$weight_table.' AS w '.
           'LEFT JOIN '.$student_table.' AS b ON a.student_id=b.student_id '.
           $groups_join;
       my $limit = ' WHERE ('.$symb_restriction.')';
       if ($time_limits) {
           $limit .= ' AND '.$time_limits;
       }
       if ($section_limits) {
           $limit .= ' AND '.$section_limits;
       }
       if ($enrollment_limits) {
           $limit .= ' AND '.$enrollment_limits;
       }
       if ($group_limits) {
           $limit .= ' AND '.$group_limits;
       }
       $request .= $limit.' GROUP BY a.student_id';
   #    &Apache::lonnet::logthis('request = '.$/.$request);
       my $sth = $dbh->prepare($request);
       $sth->execute();
       $request = 
           'SELECT AVG(score),STD(score),MAX(score),MIN(score),COUNT(score) '.
           'FROM '.$stats_table;
       my ($ave,$std,$max,$min,$count) = &execute_SQL_request($dbh,$request);
   #    &Apache::lonnet::logthis('request = '.$/.$request);
       
       $request = 'SELECT SUM(weight) FROM '.$weight_table.
           ' AS a WHERE ('.$symb_restriction.')';
       my ($max_possible) = &execute_SQL_request($dbh,$request);
       # &Apache::lonnet::logthis('request = '.$/.$request);
       return($min,$max,$ave,$std,$count,$max_possible);
   }
   
  # Handle gradable resources: exams, problems, etc  
  $currentResourceID=~/(\d+)\.(\d+)/;  
         my $partA=$1;  
         my $partB=$2;  
  if($hash{'src_'.$currentResourceID}=~  
    /\.(problem|exam|quiz|assess|survey|form)$/ &&  
    $partA eq $currentSequence &&   
            !defined($sequenceRecord{$currentSequence.':'.  
                                     $currentResourceID})) {  
             $sequenceRecord{$currentSequence.':'.$currentResourceID}++;  
     my $Problem = &Apache::lonnet::symbclean(  
   &Apache::lonnet::declutter($hash{'map_id_'.$partA}).  
   '___'.$partB.'___'.  
   &Apache::lonnet::declutter($hash{'src_'.  
  $currentResourceID}));  
   
     $cache->{$currentResourceID.':problem'}=$Problem;  
             $allkeys{$currentResourceID.':problem'}++;  
     if(!defined($cache->{$currentSequence.':problems'})) {  
  $cache->{$currentSequence.':problems'}=$currentResourceID;  
     } else {  
  $cache->{$currentSequence.':problems'}.=  
     ':'.$currentResourceID;  
     }  
             $allkeys{$currentSequence.':problems'}++;  
   
     my $meta=$hash{'src_'.$currentResourceID};  
 #            $cache->{$currentResourceID.':title'}=  
 #                &Apache::lonnet::metdata($meta,'title');  
             $cache->{$currentResourceID.':title'}=  
                 $hash{'title_'.$currentResourceID};  
             $allkeys{$currentResourceID.':title'}++;  
             $cache->{$currentResourceID.':source'}=  
                 $hash{'src_'.$currentResourceID};  
             $allkeys{$currentResourceID.':source'}++;  
   
             # Get Parts for problem  
             my %beenHere;  
             foreach (split(/\,/,&Apache::lonnet::metadata($meta,'packages'))) {  
                 if(/^\w+response_\d+.*/) {  
                     my (undef, $partId, $responseId) = split(/_/,$_);  
                     if($beenHere{'p:'.$partId} ==  0) {  
                         $beenHere{'p:'.$partId}++;  
                         if(!defined($cache->{$currentSequence.':'.  
                                             $currentResourceID.':parts'})) {  
                             $cache->{$currentSequence.':'.$currentResourceID.  
                                      ':parts'}=$partId;  
                         } else {  
                             $cache->{$currentSequence.':'.$currentResourceID.  
                                      ':parts'}.=':'.$partId;  
                         }  
                         $allkeys{$currentSequence.':'.$currentResourceID.  
                                   ':parts'}++;  
                     }  
                     if($beenHere{'r:'.$partId.':'.$responseId} == 0) {  
                         $beenHere{'r:'.$partId.':'.$responseId}++;  
                         if(!defined($cache->{$currentSequence.':'.  
                                              $currentResourceID.':'.$partId.  
                                              ':responseIDs'})) {  
                             $cache->{$currentSequence.':'.$currentResourceID.  
                                      ':'.$partId.':responseIDs'}=$responseId;  
                         } else {  
                             $cache->{$currentSequence.':'.$currentResourceID.  
                                      ':'.$partId.':responseIDs'}.=':'.  
                                                                   $responseId;  
                         }  
                         $allkeys{$currentSequence.':'.$currentResourceID.':'.  
                                      $partId.':responseIDs'}++;  
                     }  
                     if(/^optionresponse/ &&   
                        $beenHere{'o:'.$partId.':'.$currentResourceID} == 0) {  
                         $beenHere{'o:'.$partId.$currentResourceID}++;  
                         if(defined($cache->{'OptionResponses'})) {  
                             $cache->{'OptionResponses'}.= ':::'.  
                                 $currentSequence.':'.$currentResourceID.':'.  
                                 $partId.':'.$responseId;  
                         } else {  
                             $cache->{'OptionResponses'}= $currentSequence.':'.  
                                 $currentResourceID.':'.  
                                 $partId.':'.$responseId;  
                         }  
                         $allkeys{'OptionResponses'}++;  
                     }  
                 }  
             }  
         }  
   
  # if resource == finish resource, then it is the end of a sequence/page  sub count_stats {
  if($currentResourceID eq $lastResourceID) {      my ($Sections,$Groups,$enrollment,$symbs,$starttime,$endtime,$courseid)=@_;
     # pop off last resource of sequence      if (! defined($courseid)) {
     $currentResourceID=pop(@currentResource);          $courseid = $env{'request.course.id'};
     $lastResourceID=pop(@finishResource);      }
       #
     if(defined($cache->{$currentSequence.':problems'})) {      &setup_table_names($courseid);
  # Capture sequence information here      my $dbh = &Apache::lonmysql::get_dbh();
  $cache->{$currentSequence.':title'}=      #
     $hash{'title_'.$currentResourceID};      my ($section_limits,$enrollment_limits)=
                 $allkeys{$currentSequence.':title'}++;          &limit_by_section_and_status($Sections,$enrollment,'b');
                 $cache->{$currentSequence.':source'}=      my ($groups_join,$group_limits) = &limit_by_group($Groups,'b','c','d');
                     $hash{'src_'.$currentResourceID};      my $time_limits = &limit_by_start_end_time($starttime,$endtime,'a');
                 $allkeys{$currentSequence.':source'}++;      my @Symbids = map { &get_symb_id($_); } @{$symbs};
       #
                 my $totalProblems=0;      my $stats_table = &temp_table_name($courseid,'problem_stats');
                 foreach my $currentProblem (split(/\:/,      my $symb_restriction = join(' OR ',map {'a.symb_id='.$_;} @Symbids);
                                                $cache->{$currentSequence.      my $request = 'DROP TABLE '.$stats_table;
                                                ':problems'})) {      $dbh->do($request);
                     foreach (split(/\:/,$cache->{$currentSequence.':'.      $request = 
                                                    $currentProblem.          'CREATE TEMPORARY TABLE '.$stats_table.' '.
                                                    ':parts'})) {          'SELECT a.student_id,'.
                         $totalProblems++;          'SUM(a.awarded) AS count FROM '.
                     }          $performance_table.' AS a '.
                 }          'LEFT JOIN '.$student_table.' AS b ON a.student_id=b.student_id '.
  my @titleLength=split(//,$cache->{$currentSequence.          $groups_join;
                                                     ':title'});      my $limit =  ' WHERE ('.$symb_restriction.')';
                 # $extra is 3 for problems correct and 3 for space      if ($time_limits) {
                 # between problems correct and problem output          $limit .= ' AND '.$time_limits;
                 my $extra = 6;      }
  if(($totalProblems + $extra) > (scalar @titleLength)) {      if ($section_limits) {
     $cache->{$currentSequence.':columnWidth'}=          $limit .= ' AND '.$section_limits;
                         $totalProblems + $extra;      }
  } else {      if ($enrollment_limits) {
     $cache->{$currentSequence.':columnWidth'}=          $limit .= ' AND '.$enrollment_limits;
                         (scalar @titleLength);      }
  }      if ($group_limits) {
                 $allkeys{$currentSequence.':columnWidth'}++;          $limit .= ' AND '.$group_limits;
     } else {      }
                 # Remove sequence from list, if it contains no problems to      $request .= $limit.' GROUP BY a.student_id';
                 # display.  #    &Apache::lonnet::logthis('request = '.$/.$request);
                 $cache->{'orderedSequences'}=~s/$currentSequence//;      my $sth = $dbh->prepare($request);
                 $cache->{'orderedSequences'}=~s/::/:/g;      $sth->execute();
                 $cache->{'orderedSequences'}=~s/^:|:$//g;      $request = 
             }          'SELECT AVG(count),STD(count),MAX(count),MIN(count),COUNT(count) '.
           'FROM '.$stats_table;
       my ($ave,$std,$max,$min,$count) = &execute_SQL_request($dbh,$request);
   #    &Apache::lonnet::logthis('request = '.$/.$request);
       return($min,$max,$ave,$std,$count);
   }
   
     $currentSequence=pop(@sequences);  
     if($currentSequence eq $topLevelSequenceNumber) {  
  last;  
     }  
         }  
   
  # MOVE!!!  sub get_student_data {
  # move to next resource      my ($students,$courseid) = @_;
  unless(defined($hash{'to_'.$currentResourceID})) {      $courseid = $env{'request.course.id'} if (! defined($courseid));
     # big problem, need to handle.  Next is probably wrong      &setup_table_names($courseid);
             my $errorMessage = 'Big problem in ';      my $dbh = &Apache::lonmysql::get_dbh();
             $errorMessage .= 'loncoursedata::ProcessTopLevelMap.';      return undef if (! defined($dbh));
             $errorMessage .= '  bighash to_$currentResourceID not defined!';      my $request = 'SELECT '.
             &Apache::lonnet::logthis($errorMessage);          'student_id, student '.
     last;          'FROM '.$student_table;
  }      if (defined($students)) {
  my @nextResources=();          $request .= ' WHERE ('.
  foreach (split(/\,/,$hash{'to_'.$currentResourceID})) {              join(' OR ', map {'student_id='.
             if(!defined($sequenceRecord{$currentSequence.':'.                                    &get_student_id($_->{'username'},
                                         $hash{'goesto_'.$_}})) {                                                    $_->{'domain'})
                 push(@nextResources, $hash{'goesto_'.$_});                                } @$students
             }                   ).')';
  }      }
  push(@currentResource, @nextResources);      $request.= ' ORDER BY student_id';
  # Set the next resource to be processed      my $sth = $dbh->prepare($request);
  $currentResourceID=pop(@currentResource);      $sth->execute();
       if ($dbh->err) {
           &Apache::lonnet::logthis('error 2 = '.$dbh->errstr());
           &Apache::lonnet::logthis('prepared then executed '.$/.$request);
           return undef;
       }
       my $dataset = $sth->fetchall_arrayref();
       if (ref($dataset) eq 'ARRAY' && scalar(@$dataset)>0) {
           return $dataset;
     }      }
   }
   
     my @theKeys = keys(%allkeys);  sub RD_student_id      { return 0; }
     my $newkeys = join(':::', @theKeys);  sub RD_awarddetail     { return 1; }
     $cache->{'ResourceKeys'} = join(':::', $newkeys);  sub RD_response_eval   { return 2; }
     if($newkeys ne $oldkeys) {  sub RD_response_eval_2 { return 3; }
         $cache->{'ResourceUpdated'} = 'true';  sub RD_submission      { return 4; }
     } else {  sub RD_timestamp       { return 5; }
         $cache->{'ResourceUpdated'} = 'false';  sub RD_tries           { return 6; }
   sub RD_sname           { return 7; }
   
   sub get_response_data {
       my ($Sections,$Groups,$enrollment,$symb,$response,$courseid) = @_;
       return undef if (! defined($symb) || 
                  ! defined($response));
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       #
       &setup_table_names($courseid);
       my $symb_id = &get_symb_id($symb);
       if (! defined($symb_id)) {
           &Apache::lonnet::logthis('Unable to find symb for '.$symb.' in '.$courseid);
           return undef;
       }
       my $response_id = &get_part_id($response);
       if (! defined($response_id)) {
           &Apache::lonnet::logthis('Unable to find id for '.$response.' in '.$courseid);
           return undef;
       }
       #
       my $dbh = &Apache::lonmysql::get_dbh();
       return undef if (! defined($dbh));
       #
       my ($student_requirements,$enrollment_requirements) = 
           &limit_by_section_and_status($Sections,$enrollment,'d');
       my ($groups_join,$group_limits) = &limit_by_group($Groups,'d','e','f');
       my $request = 'SELECT '.
           'a.student_id, a.awarddetail, a.response_specific_value, '.
           'a.response_specific_value_2, a.submission, b.timestamp, '.
    'c.tries, d.student '.
           'FROM '.$fulldump_response_table.' AS a '.
           'LEFT JOIN '.$fulldump_timestamp_table.' AS b '.
           'ON a.symb_id=b.symb_id AND a.student_id=b.student_id AND '.
           'a.transaction = b.transaction '.
           'LEFT JOIN '.$fulldump_part_table.' AS c '.
           'ON a.symb_id=c.symb_id AND a.student_id=c.student_id AND '.        
           'a.part_id=c.part_id AND a.transaction = c.transaction '.
           'LEFT JOIN '.$student_table.' AS d '.
           'ON a.student_id=d.student_id '.
           $groups_join;
       my $limit = ' WHERE '.
           'a.symb_id='.$symb_id.' AND a.response_id='.$response_id;
       if (defined($student_requirements)) {
           $limit .= ' AND '.$student_requirements;
       }
       if (defined($enrollment_requirements)) {
           $limit .= ' AND '.$enrollment_requirements;
       }
       if (defined($group_limits)) {
           $limit .= ' AND '.$group_limits;
       }
       $request .= $limit.' ORDER BY b.timestamp';
   #    &Apache::lonnet::logthis("request =\n".$request);
       my $sth = $dbh->prepare($request);
       $sth->execute();
       if ($dbh->err) {
           &Apache::lonnet::logthis('error 3 = '.$dbh->errstr());
           &Apache::lonnet::logthis('prepared then executed '.$/.$request);
           return undef;
       }
       my $dataset = $sth->fetchall_arrayref();
       if (ref($dataset) eq 'ARRAY' && scalar(@$dataset)>0) {
           # Clear the \'s from around the submission
           for (my $i =0;$i<scalar(@$dataset);$i++) {
               $dataset->[$i]->[&RD_submission()] =~ s/(\'$|^\')//g;
           }
           return $dataset;
     }      }
   }
   
     unless (untie(%hash)) {  
         &Apache::lonnet::logthis("<font color=blue>WARNING: ".  
                                  "Could not untie coursemap $fn (browse)".  
                                  ".</font>");   
     }  
   
     return 'OK';  sub RDs_awarddetail     { return 3; }
   sub RDs_submission      { return 2; }
   sub RDs_timestamp       { return 1; }
   sub RDs_tries           { return 0; }
   sub RDs_awarded         { return 4; }
   sub RDs_response_eval   { return 5; }
   sub RDs_response_eval_2 { return 6; }
   sub RDs_part_award      { return 7; }
   
   sub get_response_data_by_student {
       my ($student,$symb,$response,$courseid) = @_;
       return undef if (! defined($symb) || 
                        ! defined($response));
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       #
       &setup_table_names($courseid);
       my $symb_id = &get_symb_id($symb);
       my $response_id = &get_part_id($response);
       #
       my $student_id = &get_student_id($student->{'username'},
                                        $student->{'domain'});
       #
       my $dbh = &Apache::lonmysql::get_dbh();
       return undef if (! defined($dbh));
       my $request = 'SELECT '.
           'c.tries, b.timestamp, a.submission, a.awarddetail, c.awarded, '.
    'a.response_specific_value, a.response_specific_value_2, c.award '.
           'FROM '.$fulldump_response_table.' AS a '.
           'LEFT JOIN '.$fulldump_timestamp_table.' AS b '.
           'ON a.symb_id=b.symb_id AND a.student_id=b.student_id AND '.
           'a.transaction = b.transaction '.
           'LEFT JOIN '.$fulldump_part_table.' AS c '.
           'ON a.symb_id=c.symb_id AND a.student_id=c.student_id AND '.        
           'a.part_id=c.part_id AND a.transaction = c.transaction '.
           'LEFT JOIN '.$student_table.' AS d '.
           'ON a.student_id=d.student_id '.
           'LEFT JOIN '.$performance_table.' AS e '.
           'ON a.symb_id=e.symb_id AND a.part_id=e.part_id AND '.
           'a.student_id=e.student_id AND c.tries=e.tries '.
           'WHERE '.
           'a.symb_id='.$symb_id.' AND a.response_id='.$response_id.
           ' AND a.student_id='.$student_id.' ORDER BY b.timestamp';
   #    &Apache::lonnet::logthis("request =\n".$request);
       my $sth = $dbh->prepare($request);
       $sth->execute();
       if ($dbh->err) {
           &Apache::lonnet::logthis('error 4 = '.$dbh->errstr());
           &Apache::lonnet::logthis('prepared then executed '.$/.$request);
           return undef;
       }
       my $dataset = $sth->fetchall_arrayref();
       if (ref($dataset) eq 'ARRAY' && scalar(@$dataset)>0) {
           # Clear the \'s from around the submission
           for (my $i =0;$i<scalar(@$dataset);$i++) {
               $dataset->[$i]->[&RDs_submission] =~ s/(\'$|^\')//g;
           }
           return $dataset;
       }
       return undef; # error occurred
 }  }
   
 =pod  sub RT_student_id { return 0; }
   sub RT_awarded    { return 1; }
   sub RT_tries      { return 2; }
   sub RT_timestamp  { return 3; }
   
   sub get_response_time_data {
       my ($sections,$groups,$enrollment,$symb,$part,$courseid) = @_;
       return undef if (! defined($symb) || 
                        ! defined($part));
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       #
       &setup_table_names($courseid);
       my $symb_id = &get_symb_id($symb);
       if (! defined($symb_id)) {
           &Apache::lonnet::logthis('Unable to find symb for '.$symb.' in '.$courseid);
           return undef;
       }
       my $part_id = &get_part_id($part);
       if (! defined($part_id)) {
           &Apache::lonnet::logthis('Unable to find id for '.$part.' in '.$courseid);
           return undef;
       }
       #
       my $dbh = &Apache::lonmysql::get_dbh();
       return undef if (! defined($dbh));
       my ($student_requirements,$enrollment_requirements) = 
           &limit_by_section_and_status($sections,$enrollment,'d');
       my ($groups_join,$group_limits) = &limit_by_group($groups,'d','e','f');
       my $request = 'SELECT '.
           'a.student_id, a.awarded, a.tries, b.timestamp '.
           'FROM '.$fulldump_part_table.' AS a '.
           'LEFT JOIN '.$fulldump_timestamp_table.' AS b '.
           'ON a.symb_id=b.symb_id AND a.student_id=b.student_id AND '.
           'a.transaction = b.transaction '.
           'LEFT JOIN '.$student_table.' as d '.
           'ON a.student_id=d.student_id '.
           $groups_join;
       my $limit = ' WHERE '.
           'a.symb_id='.$symb_id.' AND a.part_id='.$part_id;
       if (defined($student_requirements)) {
           $limit .= ' AND '.$student_requirements;
       }
       if (defined($enrollment_requirements)) {
           $limit .= ' AND '.$enrollment_requirements;
       }
       if (defined($group_limits)) {
           $limit .= ' AND '.$group_limits;  
       }
       $request .= $limit.' ORDER BY b.timestamp';
   #    &Apache::lonnet::logthis("request =\n".$request);
       my $sth = $dbh->prepare($request);
       $sth->execute();
       if ($dbh->err) {
           &Apache::lonnet::logthis('error 5 = '.$dbh->errstr());
           &Apache::lonnet::logthis('prepared then executed '.$/.$request);
           return undef;
       }
       my $dataset = $sth->fetchall_arrayref();
       if (ref($dataset) eq 'ARRAY' && scalar(@$dataset)>0) {
           return $dataset;
       }
   
 =item &ProcessClasslist()  }
   
 Taking the class list dumped from &DownloadClasslist(), all the   sub get_student_scores {
 students and their non-class information is processed using the       my ($sections,$groups,$Symbs,$enrollment,$courseid,$starttime,$endtime) = @_;
 &ProcessStudentInformation() function.  A date stamp is also recorded for      $courseid = $env{'request.course.id'} if (! defined($courseid));
 when the data was processed.      &setup_table_names($courseid);
       my $dbh = &Apache::lonmysql::get_dbh();
 Takes data downloaded for a student and breaks it up into managable pieces and       return (undef) if (! defined($dbh));
 stored in cache data.  The username, domain, class related date, PID,       my $tmptable = &temp_table_name($courseid,'temp_'.time);
 full name, and section are all processed here.      my $request = 'DROP TABLE IF EXISTS '.$tmptable;
   #    &Apache::lonnet::logthis('request = '.$/.$request);
       $dbh->do($request);
       #
       my $symb_requirements;
       if (defined($Symbs)  && @$Symbs) {
           $symb_requirements = '('.
               join(' OR ', map{ "(a.symb_id='".&get_symb_id($_->{'symb'}).
                                 "' AND a.part_id='".&get_part_id($_->{'part'}).
                                 "')"
                                 } @$Symbs).')';
       }
       #
       my ($student_requirements,$enrollment_requirements) = 
           &limit_by_section_and_status($sections,$enrollment,'b');
       #
       my ($groups_join,$group_limits) = &limit_by_group($groups,'b','d','e');
       my $time_requirements = &limit_by_start_end_time($starttime,$endtime,'a');
       ##
       $request = 'CREATE TEMPORARY TABLE IF NOT EXISTS '.$tmptable.
           ' SELECT a.student_id,SUM(a.awarded*c.weight) AS score FROM '.
           $performance_table.' AS a ';
       $request .= "LEFT JOIN ".$weight_table.' AS c ON a.symb_id=c.symb_id AND a.part_id=c.part_id ';
       if (defined($student_requirements) || defined($enrollment_requirements)) {
           $request .= ' LEFT JOIN '.$student_table.' AS b ON a.student_id=b.student_id ';
       }
       if (defined($groups_join)) {
           $request .= $groups_join;
       }
       if (defined($symb_requirements)       || 
           defined($student_requirements)    ||
           defined($enrollment_requirements) ||
           defined($group_limits) ) {
           $request .= ' WHERE ';
       }
       if (defined($symb_requirements)) {
           $request .= $symb_requirements.' AND ';
       }
       if (defined($student_requirements)) {
           $request .= $student_requirements.' AND ';
       }
       if (defined($enrollment_requirements)) {
           $request .= $enrollment_requirements.' AND ';
       }
       if (defined($time_requirements)) {
           $request .= $time_requirements.' AND ';
       }
       $request =~ s/ AND $//; # Strip of the trailing ' AND '.
       $request .= ' GROUP BY a.student_id';
   #    &Apache::lonnet::logthis("request = \n".$request);
       my $sth = $dbh->prepare($request);
       $sth->execute();
       if ($dbh->err) {
           &Apache::lonnet::logthis('error 6 = '.$dbh->errstr());
           &Apache::lonnet::logthis('prepared then executed '.$/.$request);
           return undef;
       }
       $request = 'SELECT score,COUNT(*) FROM '.$tmptable.' GROUP BY score';
   #    &Apache::lonnet::logthis("request = \n".$request);
       $sth = $dbh->prepare($request);
       $sth->execute();
       if ($dbh->err) {
           &Apache::lonnet::logthis('error 7 = '.$dbh->errstr());
           &Apache::lonnet::logthis('prepared then executed '.$/.$request);
           return undef;
       }
       my $dataset = $sth->fetchall_arrayref();
       return $dataset;
   }
   
 =over 4  
   
 Input: $cache, $classlist, $courseID, $ChartDB, $c  
   
 $cache: A hash pointer to store the data  sub setup_table_names {
       my ($courseid) = @_;
       if (! defined($courseid)) {
           $courseid = $env{'request.course.id'};
       }
       #
       if (! defined($current_course) || $current_course ne $courseid) {
           # Clear out variables
           $have_read_part_table = 0;
           undef(%ids_by_part);
           undef(%parts_by_id);
           $have_read_symb_table = 0;
           undef(%ids_by_symb);
           undef(%symbs_by_id);
           $have_read_student_table = 0;
           undef(%ids_by_student);
           undef(%students_by_id);
           $have_read_groupnames_table = 0;
           undef(%ids_by_groupname);
           #
           $current_course = $courseid;
       }
       #
       # Set up database names
       my $base_id = 'md5_'.&Digest::MD5::md5_hex($courseid);
       $symb_table               = $base_id.'_'.'symb';
       $part_table               = $base_id.'_'.'part';
       $student_table            = $base_id.'_'.'student';
       $groupnames_table         = $base_id.'_'.'groupnames';
       $students_groups_table    = $base_id.'_'.'studentgroups';
       $performance_table        = $base_id.'_'.'performance';
       $parameters_table         = $base_id.'_'.'parameters';
       $fulldump_part_table      = $base_id.'_'.'partdata';
       $fulldump_response_table  = $base_id.'_'.'responsedata';
       $fulldump_timestamp_table = $base_id.'_'.'timestampdata';
       $weight_table             = $base_id.'_'.'weight';
       #
       @Tables = (
                  $symb_table,
                  $part_table,
                  $student_table,
                  $groupnames_table,
                  $students_groups_table,
                  $performance_table,
                  $parameters_table,
                  $fulldump_part_table,
                  $fulldump_response_table,
                  $fulldump_timestamp_table,
                  $weight_table,
                  );
       return;
   }
   
 $classlist:  The hash of data collected about a student from   sub temp_table_name {
 &DownloadClasslist().  The hash contains a list of students, a pointer       my ($courseid,$affix) = @_;
 to a hash of student information for each student, and each students section       my $base_id = 'md5_'.&Digest::MD5::md5_hex($courseid);
 number.      return $base_id.'_'.$affix;
   }
 $courseID:  The course ID  
   
 $ChartDB:  The name of the cache database file.  
   
 $c:  The connection class used to determine if an abort has been sent to the   
 browser  
   
 Output: @names  
   
 @names:  An array of students whose information has been processed, and are to   
 be considered in an arbitrary order.  The entries in @names are of the form  
 username:domain.  
   
 The values in $cache are as follows:  
   
  *NOTE: for the following $name implies username:domain  
  $name.':error'                  only defined if an error occured.  Value  
                                  contains the error message  
  $name.':lastDownloadTime'       unconverted time of the last update of a  
                                  student\'s course data  
  $name.'updateTime'              coverted time of the last update of a   
                                  student\'s course data  
  $name.':username'               username of a student  
  $name.':domain'                 domain of a student  
  $name.':fullname'               full name of a student  
  $name.':id'                     PID of a student  
  $name.':Status'                 active/expired status of a student  
  $name.':section'                section of a student  
   
 =back  
   
 =cut  } # End scope of table identifiers
   
 sub ProcessClasslist {  
     my ($cache,$classlist,$courseID,$c)=@_;  
     my @names=();  
   
     $cache->{'ClasslistTimeStamp'}=$classlist->{'lastDownloadTime'};  
     if($classlist->{'UpToDate'} eq 'true') {  
         return split(/:::/,$cache->{'NamesOfStudents'});;  
     }  
   
     foreach my $name (keys(%$classlist)) {  
         if($name =~ /\:section/ || $name =~ /\:studentInformation/ ||  sub CL_SDOM     { return 0; }
            $name eq '' || $name eq 'UpToDate' || $name eq 'lastDownloadTime') {  sub CL_SNAME    { return 1; }
             next;  sub CL_END      { return 2; }
         }  sub CL_START    { return 3; }
         if($c->aborted()) {  sub CL_ID       { return 4; }
             return ();  sub CL_SECTION  { return 5; }
         }  sub CL_FULLNAME { return 6; }
         my $studentInformation = $classlist->{$name.':studentInformation'};  sub CL_STATUS   { return 7; }
         my $date = $classlist->{$name};  sub CL_TYPE     { return 8; }
         my ($studentName,$studentDomain) = split(/\:/,$name);  sub CL_LOCKEDTYPE   { return 9; }
   sub CL_CREDITS  { return 10; }
         $cache->{$name.':username'}=$studentName;  sub CL_INSTSEC { return 11; }
         $cache->{$name.':domain'}=$studentDomain;  sub CL_GROUP    { return 12; }
         # Initialize timestamp for student  sub CL_PERMANENTEMAIL { return 13; }
         if(!defined($cache->{$name.':lastDownloadTime'})) {  sub CL_ROLE     { return 14; }
             $cache->{$name.':lastDownloadTime'}='Not downloaded';  sub CL_EXTENT   { return 15; }
             $cache->{$name.':updateTime'}=' Not updated';  sub CL_PHOTO   { return 16; }
         }  sub CL_THUMBNAIL { return 17; }
   sub CL_AUTHORQUOTA { return 18; }
         my $error = 0;  sub CL_AUTHORUSAGE { return 19; }
         foreach(keys(%$studentInformation)) {  
             if(/^(con_lost|error|no_such_host)/i) {  sub get_classlist {
                 $cache->{$name.':error'}=      my ($cdom,$cnum) = @_;
                     'Could not download student environment data.';      my $cid = $cdom.'_'.$cnum;
                 $cache->{$name.':fullname'}='';      if (!defined($cdom) || !defined($cnum)) {
                 $cache->{$name.':id'}='';   $cid =  $env{'request.course.id'};
                 $error = 1;   $cdom = $env{'course.'.$cid.'.domain'};
             }   $cnum = $env{'course.'.$cid.'.num'};
         }      }
         next if($error);      my $now = time;
         push(@names,$name);      #
         $cache->{$name.':fullname'}=&ProcessFullName(      my %classlist=&Apache::lonnet::dump('classlist',$cdom,$cnum);
                                           $studentInformation->{'lastname'},      while (my ($student,$info) = each(%classlist)) {
                                           $studentInformation->{'generation'},          if ($student =~ /^(con_lost|error|no_such_host)/i) {
                                           $studentInformation->{'firstname'},              &Apache::lonnet::logthis('get_classlist error for '.$cid.':'.$student);
                                           $studentInformation->{'middlename'});              return undef;
         $cache->{$name.':id'}=$studentInformation->{'id'};          }
           my ($sname,$sdom) = split(/:/,$student);
         my ($end, $start)=split(':',$date);          my @Values = split(/:/,$info);
         $courseID=~s/\_/\//g;          my ($end,$start,$id,$section,$fullname,$type,$lockedtype,$credits,$instsec);
         $courseID=~s/^(\w)/\/$1/;          if (@Values > 2) {
               ($end,$start,$id,$section,$fullname,$type,$lockedtype,$credits,$instsec) = @Values;
         my $sec='';          } else { # We have to get the data ourselves
         my $sectionData = $classlist->{$name.':sections'};              ($end,$start) = @Values;
         foreach my $key (keys (%$sectionData)) {              $section = &Apache::lonnet::getsection($sdom,$sname,$cid);
             my $value = $sectionData->{$key};              my %info=&Apache::lonnet::get('environment',
             if ($key=~/^$courseID(?:\/)*(\w+)*\_st$/) {                                            ['firstname','middlename',
                 my $tempsection=$1;                                             'lastname','generation','id'],
                 if($key eq $courseID.'_st') {                                            $sdom, $sname);
                     $tempsection='';              my ($tmp) = keys(%info);
                 }              if ($tmp =~/^(con_lost|error|no_such_host)/i) {
                 my (undef,$roleend,$rolestart)=split(/\_/,$value);                  $fullname = 'not available';
                 if($roleend eq $end && $rolestart eq $start) {                  $id = 'not available';
                     $sec = $tempsection;                  &Apache::lonnet::logthis('unable to retrieve environment '.
                     last;                                           'for '.$sname.':'.$sdom);
               } else {
                   $fullname = &Apache::lonnet::format_name(@info{qw/firstname middlename lastname generation/},'lastname');
                   $id = $info{'id'};
               }
               # Update the classlist with this students information
               if ($fullname ne 'not available') {
    my $enrolldata = join(':',$end,$start,$id,$section,$fullname);
    my $reply=&Apache::lonnet::cput('classlist',
                                                   {$student => $enrolldata},
                                                   $cdom,$cnum);
                   if ($reply !~ /^(ok|delayed)/) {
                       &Apache::lonnet::logthis('Unable to update classlist for '.
                                                'student '.$sname.':'.$sdom.
                                                ' error:'.$reply);
                 }                  }
             }              }
         }          }
   
         my $status='Expired';          my $status='Expired';
         if(((!$end) || time < $end) && ((!$start) || (time > $start))) {          if(((!$end) || $now < $end) && ((!$start) || ($now > $start))) {
             $status='Active';              $status='Active';
         }          }
         $cache->{$name.':Status'}=$status;          if(($now < $start) && ((!$end) || $now < $end )) {
         $cache->{$name.':section'}=$sec;              $status='Future';
           }
           $classlist{$student} = 
               [$sdom,$sname,$end,$start,$id,$section,$fullname,$status,$type,
                $lockedtype,$credits,$instsec];
       }
       if (wantarray()) {
           return (\%classlist,['domain','username','end','start','id',
                                'section','fullname','status','type',
                                'lockedtype','credits','instsec']);
       } else {
           return \%classlist;
       }
   }
   
   sub get_group_memberships {
       my ($classlist,$keylist,$cdom,$cnum) = @_;
   
         if($sec eq '' || !defined($sec) || $sec eq ' ') {      return ({},{}) if (!ref($classlist) || !ref($keylist));
             $sec = 'none';  
       my $cid = $cdom.'_'.$cnum;
       if (!defined($cdom) || !defined($cnum)) {
           $cid =  $env{'request.course.id'};
           $cdom = $env{'course.'.$cid.'.domain'};
           $cnum = $env{'course.'.$cid.'.num'};
       }
       my (%classgroups,%studentgroups);
       my $now = time;
       my $access_end = $env{'course.'.$cid.'.default_enrollment_end_date'};
       my %curr_groups =&Apache::longroup::coursegroups($cdom,$cnum);
       if (%curr_groups) {
           my $grpindex = &CL_GROUP();
           my %groupmemberhash = 
       &Apache::lonnet::get_group_membership($cdom,$cnum);
           foreach my $student (keys(%{$classlist})) {
               %{$classgroups{$student}} = ();
               my $hasgroup = 0;
               foreach my $status ('previous','future','active','aftercourse') {
                   %{$classgroups{$student}{$status}} = ();
               }
               foreach my $group (keys(%curr_groups)) {
                   if (defined($groupmemberhash{$group.':'.$student})) {
                       my ($end,$start) = split(/:/,$groupmemberhash{$group.':'.
                                                                       $student});
                       if ($start == -1) {
                           next;
                       } else {
                           $studentgroups{$group} ++;
                           $hasgroup = 1;
                           if ($end && $end < $now) {
                               $classgroups{$student}{'previous'}{$group} =
                                            $groupmemberhash{$group.':'.$student};
                               if ($classlist->{$student}[&CL_STATUS()] eq 'Expired') {
                                   if ($access_end && $access_end < $now) {
                                       if ($access_end - $end < 86400) {
                                           $classgroups{$student}{'aftercourse'}{$group} = $groupmemberhash{$group.':'.$student};
                                       }
                                   }
                               }
                           } elsif ($now > $start) {
                               if (!$end || $end > $now) {
                                   $classgroups{$student}{'active'}{$group} =
                                            $groupmemberhash{$group.':'.$student};
                               }
                           } else {
                               $classgroups{$student}{'future'}{$group} =
                                            $groupmemberhash{$group.':'.$student};
                           }
                       }
                   }
               }
               if (!$hasgroup) {
                   $studentgroups{'none'} ++;
               } else {
                   $classlist->{$student}->[$grpindex] = join(',',
                                 sort(keys(%{$classgroups{$student}{'active'}})));
               }
         }          }
         if(defined($cache->{'sectionList'})) {      }
             if($cache->{'sectionList'} !~ /(^$sec:|^$sec$|:$sec$|:$sec:)/) {      return (\%classgroups,\%studentgroups);
                 $cache->{'sectionList'} .= ':'.$sec;  }
                                                                                      
   sub get_students_groups {
       my ($student,$enrollment_status,$classgroups) = @_;
       my @studentsgroups = ();
       if (ref($$classgroups{$student}{'active'}) eq 'HASH') {
           push(@studentsgroups,keys(%{$$classgroups{$student}{'active'}}));
       }
       if ($enrollment_status eq 'Any') {
           foreach my $status ('previous','future') {
               if (ref($$classgroups{$student}{$status}) eq 'HASH') {
                   push(@studentsgroups,keys(%{$$classgroups{$student}{$status}}));
             }              }
         } else {          }
             $cache->{'sectionList'} = $sec;      } else {
           if (ref($$classgroups{$student}{'aftercourse'}) eq 'HASH') {
               push(@studentsgroups,keys(%{$$classgroups{$student}{'aftercourse'}}));
         }          }
     }      }
       return @studentsgroups;
   }
   
     $cache->{'ClasslistTimestamp'}=time;  
     $cache->{'NamesOfStudents'}=join(':::',@names);  
   
     return @names;  # ----- END HELPER FUNCTIONS --------------------------------------------
 }  
   1;
   __END__
   
   
 =pod  =pod
   
 =item &ProcessStudentData()  =head1 NAME
   
   Apache::loncoursedata
   
   =head1 SYNOPSIS
   
   Set of functions that download and process student and course information.
   
   =head1 PACKAGES USED
   
     Apache::lonnet
     Apache::longroup
     Time::HiRes
     Apache::lonmysql
     LONCAPA
     Digest::MD5
    
   =head1 DOWNLOAD INFORMATION
   
   This section contains all the functions that get data from other servers 
   and/or itself.
   
   
   
   =head1 LOCAL DATA CACHING SUBROUTINES
   
   The local caching is done using MySQL.  There is no fall-back implementation
   if MySQL is not running.
   
   The programmers interface is to call &get_current_state() or some other
   primary interface subroutine (described below).  The internals of this 
   storage system are documented here.
   
   There are six tables used to store student performance data (the results of
   a dumpcurrent).  Each of these tables is created in MySQL with a name of
   $courseid_*****, where ***** is 'symb', 'part', or whatever is appropriate 
   for the table.  The tables and their purposes are described below.
   
 Takes the course data downloaded for a student in   Some notes before we get started.
 &DownloadCourseInformation() and breaks it up into key value pairs  
 to be stored in the cached data.  The keys are comprised of the   Each table must have a PRIMARY KEY, which is a column or set of columns which
 $username:$domain:$keyFromCourseDatabase.  The student username:domain is  will serve to uniquely identify a row of data.  NULL is not allowed!
 stored away signifying that the students information has been downloaded and   
 can be reused from cached data.  INDEXes work best on integer data.
   
   JOIN is used to combine data from many tables into one output.
   
   lonmysql.pm is used for some of the interface, specifically the table creation
   calls.  The inserts are done in bulk by directly calling the database handler.
   The SELECT ... JOIN statement used to retrieve the data does not have an
   interface in lonmysql.pm and I shudder at the thought of writing one.
   
   =head2 Table Descriptions
   
 =over 4  =over 4
   
 Input: $cache, $courseData, $name  =head2 Tables used to store meta information
   
 $cache: A hash pointer to store data  The following tables hold data required to keep track of the current status
   of a students data in the tables or to look up the students data in the tables.
   
 $courseData:  A hash pointer that points to the course data downloaded for a   =over 4
 student.  
   
 $name:  username:domain  =item C<$symb_table>
   
 Output: None  The symb_table has two columns.  The first is a 'symb_id' and the second
   is the text name for the 'symb' (limited to 64k).  The 'symb_id' is generated
   automatically by MySQL so inserts should be done on this table with an
   empty first element.  This table has its PRIMARY KEY on the 'symb_id'.
   
 *NOTE:  There is no output, but an error message is stored away in the cache   =item C<$part_table>
 data.  This is checked in &FormatStudentData().  The key username:domain:error   
 will only exist if an error occured.  The error is an error from   
 &DownloadCourseInformation().  
   
 =back  The part_table has two columns.  The first is a 'part_id' and the second
   is the text name for the 'part' (limited to 100 characters).  The 'part_id' is
   generated automatically by MySQL so inserts should be done on this table with
   an empty first element.  This table has its PRIMARY KEY on the 'part' (100
   characters) and a KEY on 'part_id'.
   
 =cut  =item C<$student_table>
   
 sub ProcessStudentData {  The student_table has 7 columns.  The first is a 'student_id' assigned by 
     my ($cache,$courseData,$name)=@_;  MySQL.  The second is 'student' which is username:domain.  The third through
   fifth are 'section', 'status' (enrollment status), and 'classification' 
   (to be used in the future).  The sixth and seventh ('updatetime' and 
   'fullupdatetime') contain the time of last update and full update of student
   data.  This table has its PRIMARY KEY on the 'student_id' column and is indexed
   on 'student', 'section', and 'status'.
   
     if(!&CheckDateStampError($courseData, $cache, $name)) {  =item C<$groupnames_table>
         return;  
     }  
   
     # This little delete thing, should not be here.  Move some other  The groupnames_table has 2 columns.  The first is a 'group_id' assigned by 
     # time though.  MySQL.  The second is 'groupname' which is the name of the group in the course.
     if(defined($cache->{$name.':keys'})) {  
  foreach (split(':::', $cache->{$name.':keys'})) {  
     delete $cache->{$name.':'.$_};  
  }  
         delete $cache->{$name.':keys'};  
     }  
   
     my %courseKeys;  =item C<$students_groups_table>
     # user name:domain was prepended earlier in DownloadCourseInformation  
     foreach (keys %$courseData) {  
  my $currentKey = $_;  
  $currentKey =~ s/^$name//;  
  $courseKeys{$currentKey}++;  
         $cache->{$_}=$courseData->{$_};  
     }  
   
     $cache->{$name.':keys'} = join(':::', keys(%courseKeys));  The students_groups_table has 2 columns.  The first is the 'student_id', and the 
   second is the 'group_id'. These two columns comprise the PRIMARY KEY for this 
   table, as an individual student may be affiliated with more than one group at
   any time. This table is indexed on both student_id and group_id.
   
     return;  =back 
 }  
   
 =pod  =head2 Tables used to store current status data
   
   The following tables store data only about the students current status on 
   a problem, meaning only the data related to the last attempt on a problem.
   
   =over 4
   
   =item C<$performance_table>
   
   The performance_table has 9 columns.  The first three are 'symb_id', 
   'student_id', and 'part_id'.  These comprise the PRIMARY KEY for this table
   and are directly related to the $symb_table, $student_table, and $part_table
   described above.  MySQL does better indexing on numeric items than text,
   so we use these three "index tables".  The remaining columns are
   'solved', 'tries', 'awarded', 'award', 'awarddetail', and 'timestamp'.
   These are either the MySQL type TINYTEXT or various integers ('tries' and 
   'timestamp').  This table has KEYs of 'student_id' and 'symb_id'.
   For use of this table, see the functions described below.
   
   =item C<$parameters_table>
   
   The parameters_table holds the data that does not fit neatly into the
   performance_table.  The parameters table has four columns: 'symb_id',
   'student_id', 'parameter', and 'value'.  'symb_id', 'student_id', and
   'parameter' comprise the PRIMARY KEY for this table.  'parameter' is 
   limited to 255 characters.  'value' is limited to 64k characters.
   
   =back
   
 =item &ExtractStudentData()  =head2 Tables used for storing historic data
   
 HISTORY: This function originally existed in every statistics module,  The following tables are used to store almost all of the transactions a student
 and performed different tasks, the had some overlap.  Due to the need  has made on a homework problem.  See loncapa/docs/homework/datastorage for 
 for the data from the different modules, they were combined into  specific information about each of the parameters stored.  
 a single function.  
   
 This function now extracts all the necessary course data for a student  
 from what was downloaded from their homeserver.  There is some extra  
 time overhead compared to the ProcessStudentInformation function, but  
 it would have had to occurred at some point anyways.  This is now  
 typically called while downloading the data it will process.  It is  
 the brother function to ProcessStudentInformation.  
   
 =over 4  =over 4
   
 Input: $input, $output, $data, $name  =item C<$fulldump_response_table>
   
   The response table holds data (documented in loncapa/docs/homework/datastorage)
   associated with a particular response id which is stored when a student 
   attempts a problem.  The following are the columns of the table, in order:
   'symb_id','part_id','response_id','student_id','transaction','tries',
   'awarddetail', 'response_specific', 'response_specific_value',
   'response_specific_2', 'response_specific_value_2', and 'submission
   (the text of the students submission).  The primary key is based on the
   first five columns listed above.
   
   =item C<$fulldump_part_table()>
   
   The part table holds data (documented in loncapa/docs/homework/datastorage)
   associated with a particular part id which is stored when a student attempts
   a problem.  The following are the columns of the table, in order:
   'symb_id','part_id','student_id','transaction','tries','award','awarded',
   and 'previous'.  The primary key is based on the first five columns listed 
   above.
   
   =item C<$fulldump_timestamp_table()>
   
   The timestamp table holds the timestamps of the transactions which are
   stored in $fulldump_response_table and $fulldump_part_table.  This data is
   about both the response and part data.  Columns: 'symb_id','student_id',
   'transaction', and 'timestamp'.  
   The primary key is based on the first 3 columns.
   
   =item C<$weight_table()>
   
   The weight table holds the weight for the problems used in the class.
   Whereas the weight of a problem can vary by section and student the data
   here is applied to the class as a whole.
   Columns: 'symb_id','part_id','response_id','weight'.
   
   =back
   
   
   =head1 IMPORTANT SUBROUTINES
   
 $input: A hash that contains the input data to be processed  Here is a brief overview of the subroutines which are likely to be of 
   interest:
   
   =over 4
   
 $output: A hash to contain the processed data  =item C<&get_current_state()>
   
 $data: A hash containing the information on what is to be  programmers interface.
 processed and how (basically).  
   
 $name:  username:domain  =item C<&init_dbs()>
   
 The input is slightly different here, but is quite simple.  table creation
 It is currently used where the $input, $output, and $data  
 can and are often the same hashes, but they do not need  
 to be.  
   
 Output: None  =item C<&update_student_data()>
   
 *NOTE:  There is no output, but an error message is stored away in the cache   data storage calls
 data.  This is checked in &FormatStudentData().  The key username:domain:error   
 will only exist if an error occured.  The error is an error from   =item C<&get_student_data_from_performance_cache()>
 &DownloadCourseInformation().  
   data retrieval
   
 =back  =back
   
 =cut  =head1 OTHER SUBROUTINES
   
 sub ExtractStudentData {  =over 4
     my ($input, $output, $data, $name)=@_;  
   
     if(!&CheckDateStampError($input, $data, $name)) {  =item C<&make_into_hash($values)>
         return;  
     }  
   
     # This little delete thing, should not be here.  Move some other  Returns a reference to a hash as described by $values.  $values is
     # time though.  assumed to be the result of 
     my %allkeys;      join(':',map {&escape($_)} %orighash);
     if(defined($output->{$name.':keys'})) {  
  foreach (split(':::', $output->{$name.':keys'})) {  
     delete $output->{$name.':'.$_};  
  }  
         delete $output->{$name.':keys'};  
     }  
   
     my ($username,$domain)=split(':',$name);  This is a helper function for get_current_state.
   
     my $Version;  =item C<&init_dbs()>
     my $problemsCorrect = 0;  
     my $totalProblems   = 0;  
     my $problemsSolved  = 0;  
     my $numberOfParts   = 0;  
     my $totalAwarded    = 0;  
     foreach my $sequence (split(':', $data->{'orderedSequences'})) {  
         foreach my $problemID (split(':', $data->{$sequence.':problems'})) {  
             my $problem = $data->{$problemID.':problem'};  
             my $LatestVersion = $input->{$name.':version:'.$problem};  
   
             # Output dashes for all the parts of this problem if there  
             # is no version information about the current problem.  
             $output->{$name.':'.$problemID.':NoVersion'} = 'false';  
             $allkeys{$name.':'.$problemID.':NoVersion'}++;  
             if(!$LatestVersion) {  
                 foreach my $part (split(/\:/,$data->{$sequence.':'.  
                                                       $problemID.  
                                                       ':parts'})) {  
                     $output->{$name.':'.$problemID.':'.$part.':tries'} = 0;  
                     $output->{$name.':'.$problemID.':'.$part.':awarded'} = 0;  
                     $output->{$name.':'.$problemID.':'.$part.':code'} = ' ';  
     $allkeys{$name.':'.$problemID.':'.$part.':tries'}++;  
     $allkeys{$name.':'.$problemID.':'.$part.':awarded'}++;  
     $allkeys{$name.':'.$problemID.':'.$part.':code'}++;  
                     $totalProblems++;  
                 }  
                 $output->{$name.':'.$problemID.':NoVersion'} = 'true';  
                 next;  
             }  
   
             my %partData=undef;  Input: course id
             # Initialize part data, display skips correctly  
             # Skip refers to when a student made no submissions on that  
             # part/problem.  
             foreach my $part (split(/\:/,$data->{$sequence.':'.  
                                                  $problemID.  
                                                  ':parts'})) {  
                 $partData{$part.':tries'}=0;  
                 $partData{$part.':code'}=' ';  
                 $partData{$part.':awarded'}=0;  
                 $partData{$part.':timestamp'}=0;  
                 foreach my $response (split(':', $data->{$sequence.':'.  
                                                          $problemID.':'.  
                                                          $part.':responseIDs'})) {  
                     $partData{$part.':'.$response.':submission'}='';  
                 }  
             }  
   
             # Looping through all the versions of each part, starting with the  Output: 0 on success, positive integer on error
             # oldest version.  Basically, it gets the most recent   
             # set of grade data for each part.  
             my @submissions = ();  
     for(my $Version=1; $Version<=$LatestVersion; $Version++) {  
                 foreach my $part (split(/\:/,$data->{$sequence.':'.  
                                                      $problemID.  
                                                      ':parts'})) {  
   
                     if(!defined($input->{"$name:$Version:$problem".  
                                          ":resource.$part.solved"})) {  
                         # No grade for this submission, so skip  
                         next;  
                     }  
   
                     my $tries=0;  This routine issues the calls to lonmysql to create the tables used to
                     my $code=' ';  store student data.
                     my $awarded=0;  
   
                     $tries = $input->{$name.':'.$Version.':'.$problem.  
                                       ':resource.'.$part.'.tries'};  
                     $awarded = $input->{$name.':'.$Version.':'.$problem.  
                                         ':resource.'.$part.'.awarded'};  
   
                     $partData{$part.':awarded'}=($awarded) ? $awarded : 0;  
                     $partData{$part.':tries'}=($tries) ? $tries : 0;  
   
                     $partData{$part.':timestamp'}=$input->{$name.':'.$Version.':'.  
                                                            $problem.  
                                                            ':timestamp'};  
                     if(!$input->{$name.':'.$Version.':'.$problem.':resource.'.$part.  
                                  '.previous'}) {  
                         foreach my $response (split(':',  
                                                    $data->{$sequence.':'.  
                                                            $problemID.':'.  
                                                            $part.':responseIDs'})) {  
                             @submissions=($input->{$name.':'.$Version.':'.  
                                                    $problem.  
                                                    ':resource.'.$part.'.'.  
                                                    $response.'.submission'},  
                                           @submissions);  
                         }  
                     }  
   
                     my $val = $input->{$name.':'.$Version.':'.$problem.  item C<&delete_caches()>
                                        ':resource.'.$part.'.solved'};  
                     if    ($val eq 'correct_by_student')   {$code = '*';}   
                     elsif ($val eq 'correct_by_override')  {$code = '+';}  
                     elsif ($val eq 'incorrect_attempted')  {$code = '.';}   
                     elsif ($val eq 'incorrect_by_override'){$code = '-';}  
                     elsif ($val eq 'excused')              {$code = 'x';}  
                     elsif ($val eq 'ungraded_attempted')   {$code = '#';}  
                     else                                   {$code = ' ';}  
                     $partData{$part.':code'}=$code;  
                 }  
             }  
   
             foreach my $part (split(/\:/,$data->{$sequence.':'.$problemID.  This routine drops all the tables associated with a course from the 
                                                  ':parts'})) {  MySQL database.
                 $output->{$name.':'.$problemID.':'.$part.':wrong'} =   
                     $partData{$part.':tries'};  
  $allkeys{$name.':'.$problemID.':'.$part.':wrong'}++;  
   
                 if($partData{$part.':code'} eq '*') {  
                     $output->{$name.':'.$problemID.':'.$part.':wrong'}--;  
                     $problemsCorrect++;  
                 } elsif($partData{$part.':code'} eq '+') {  
                     $output->{$name.':'.$problemID.':'.$part.':wrong'}--;  
                     $problemsCorrect++;  
                 }  
   
                 $output->{$name.':'.$problemID.':'.$part.':tries'} =   Input: course id (optional, determined by environment if omitted) 
                     $partData{$part.':tries'};  
                 $output->{$name.':'.$problemID.':'.$part.':code'} =  
                     $partData{$part.':code'};  
                 $output->{$name.':'.$problemID.':'.$part.':awarded'} =  
                     $partData{$part.':awarded'};  
  $allkeys{$name.':'.$problemID.':'.$part.':tries'}++;  
  $allkeys{$name.':'.$problemID.':'.$part.':code'}++;  
  $allkeys{$name.':'.$problemID.':'.$part.':awarded'}++;  
   
                 $totalAwarded += $partData{$part.':awarded'};  
                 $output->{$name.':'.$problemID.':'.$part.':timestamp'} =  
                     $partData{$part.':timestamp'};  
  $allkeys{$name.':'.$problemID.':'.$part.':timestamp'}++;  
   
                 foreach my $response (split(':', $data->{$sequence.':'.  
                                                          $problemID.':'.  
                                                          $part.':responseIDs'})) {  
                     $output->{$name.':'.$problemID.':'.$part.':'.$response.  
                               ':submission'}=join(':::',@submissions);  
     $allkeys{$name.':'.$problemID.':'.$part.':'.$response.  
      ':submission'}++;  
                 }  
   
                 if($partData{$part.':code'} ne 'x') {  Returns: nothing
                     $totalProblems++;  
                 }  
             }  
         }  
   
         $output->{$name.':'.$sequence.':problemsCorrect'} = $problemsCorrect;  =item C<&get_part_id()>
  $allkeys{$name.':'.$sequence.':problemsCorrect'}++;  
         $problemsSolved += $problemsCorrect;  
  $problemsCorrect=0;  
     }  
   
     $output->{$name.':problemsSolved'} = $problemsSolved;  Get the MySQL id of a problem part string.
     $output->{$name.':totalProblems'} = $totalProblems;  
     $output->{$name.':totalAwarded'} = $totalAwarded;  
     $allkeys{$name.':problemsSolved'}++;  
     $allkeys{$name.':totalProblems'}++;  
     $allkeys{$name.':totalAwarded'}++;  
   
     $output->{$name.':keys'} = join(':::', keys(%allkeys));  Input: $part
   
     return;  Output: undef on error, integer $part_id on success.
 }  
   
 sub LoadDiscussion {  =item C<&get_part()>
     my ($courseID)=@_;  
     my %Discuss=();  
     my %contrib=&Apache::lonnet::dump(  
                 $courseID,  
                 $ENV{'course.'.$courseID.'.domain'},  
                 $ENV{'course.'.$courseID.'.num'});  
     
     #my %contrib=&DownloadCourseInformation($name, $courseID, 0);  
   
     foreach my $temp(keys %contrib) {  
  if ($temp=~/^version/) {  
     my $ver=$contrib{$temp};  
     my ($dummy,$prb)=split(':',$temp);  
     for (my $idx=1; $idx<=$ver; $idx++ ) {  
  my $name=$contrib{"$idx:$prb:sendername"};  
  $Discuss{"$name:$prb"}=$idx;  
     }  
  }  
     }         
   
     return \%Discuss;  Get the string describing a part from the MySQL id of the problem part.
 }  
   
 # ----- END PROCESSING FUNCTIONS ---------------------------------------  Input: $part_id
   
 =pod  Output: undef on error, $part string on success.
   
 =head1 HELPER FUNCTIONS  =item C<&get_symb_id()>
   
 These are just a couple of functions do various odd and end   Get the MySQL id of a symb.
 jobs.  There was also a couple of bulk functions added.  These are  
 &DownloadStudentCourseData(), &DownloadStudentCourseDataSeparate(), and  
 &CheckForResidualDownload().  These functions now act as the interface  
 for downloading student course data.  The statistical modules should  
 no longer make the calls to dump and download and process etc.  They  
 make calls to these bulk functions to get their data.  
   
 =cut  Input: $symb
   
 # ----- HELPER FUNCTIONS -----------------------------------------------  Output: undef on error, integer $symb_id on success.
   
 sub CheckDateStampError {  =item C<&get_symb()>
     my ($courseData, $cache, $name)=@_;  
     if($courseData->{$name.':UpToDate'} eq 'true') {  
         $cache->{$name.':lastDownloadTime'} =   
             $courseData->{$name.':lastDownloadTime'};  
         if($courseData->{$name.':lastDownloadTime'} eq 'Not downloaded') {  
             $cache->{$name.':updateTime'} = ' Not updated';  
         } else {  
             $cache->{$name.':updateTime'}=  
                 localtime($courseData->{$name.':lastDownloadTime'});  
         }  
         return 0;  
     }  
   
     $cache->{$name.':lastDownloadTime'}=$courseData->{$name.':lastDownloadTime'};  
     if($courseData->{$name.':lastDownloadTime'} eq 'Not downloaded') {  
         $cache->{$name.':updateTime'} = ' Not updated';  
     } else {  
         $cache->{$name.':updateTime'}=  
             localtime($courseData->{$name.':lastDownloadTime'});  
     }  
   
     if(defined($courseData->{$name.':error'})) {  Get the symb associated with a MySQL symb_id.
         $cache->{$name.':error'}=$courseData->{$name.':error'};  
         return 0;  
     }  
   
     return 1;  Input: $symb_id
 }  
   
 =pod  Output: undef on error, $symb on success.
   
 =item &ProcessFullName()  =item C<&get_student_id()>
   
 Takes lastname, generation, firstname, and middlename (or some partial  Get the MySQL id of a student.
 set of this data) and returns the full name version as a string.  Format  
 is Lastname generation, firstname middlename or a subset of this.  
   
 =cut  Input: $sname, $dom
   
 sub ProcessFullName {  Output: undef on error, integer $student_id on success.
     my ($lastname, $generation, $firstname, $middlename)=@_;  
     my $Str = '';  
   
     # Strip whitespace preceeding & following name components.  
     $lastname   =~ s/(\s+$|^\s+)//g;  
     $generation =~ s/(\s+$|^\s+)//g;  
     $firstname  =~ s/(\s+$|^\s+)//g;  
     $middlename =~ s/(\s+$|^\s+)//g;  
   
     if($lastname ne '') {  
  $Str .= $lastname;  
  $Str .= ' '.$generation if ($generation ne '');  
  $Str .= ',';  
         $Str .= ' '.$firstname  if ($firstname ne '');  
         $Str .= ' '.$middlename if ($middlename ne '');  
     } else {  
         $Str .= $firstname      if ($firstname ne '');  
         $Str .= ' '.$middlename if ($middlename ne '');  
         $Str .= ' '.$generation if ($generation ne '');  
     }  
   
     return $Str;  =item C<&get_student()>
 }  
   
 =pod  Get student username:domain associated with the MySQL student_id.
   
   Input: $student_id
   
   Output: undef on error, string $student (username:domain) on success.
   
   =item C<&clear_internal_caches()>
   
   Causes the internal caches used in get_student_id, get_student,
   get_symb_id, get_symb, get_part_id, and get_part to be undef'd.
   
   Needs to be called before the first operation with the MySQL database
   for a given Apache request.
   
   =item C<&update_full_student_data($sname,$sdom,$courseid)>
   
   Does a lonnet::dump on a student to populate the courses tables.
   
   Input: $sname, $sdom, $courseid
   
   Output: $returnstatus
   
   $returnstatus is a string describing any errors that occurred.  'okay' is the
   default.
   
   This subroutine loads a students data using lonnet::dump and inserts
   it into the MySQL database.  The inserts are done on three tables, 
   $fulldump_response_table, $fulldump_part_table, and $fulldump_timestamp_table.
   The INSERT calls are made directly by this subroutine, not through lonmysql 
   because we do a 'bulk'insert which takes advantage of MySQLs non-SQL 
   compliant INSERT command to insert multiple rows at a time.  
   If anything has gone wrong during this process, $returnstatus is updated with 
   a description of the error.
   
   Once the "fulldump" tables are updated, the tables used for chart and
   spreadsheet (which hold only the current state of the student on their
   homework, not historical data) are updated.  If all updates have occurred 
   successfully, $student_table is updated to reflect the time of the update.
   
   Notice we do not insert the data and immediately query it.  This means it
   is possible for there to be data returned this first time that is not 
   available the second time.  CYA.
   
   
   =item C<&update_student_data()>
   
   Input: $sname, $sdom, $courseid
   
   Output: $returnstatus, \%student_data
   
   $returnstatus is a string describing any errors that occurred.  'okay' is the
   default.
   \%student_data is the data returned by a call to lonnet::currentdump.
   
   This subroutine loads a students data using lonnet::currentdump and inserts
   it into the MySQL database.  The inserts are done on two tables, 
   $performance_table and $parameters_table.  $parameters_table holds the data 
   that is not included in $performance_table.  See the description of 
   $performance_table elsewhere in this file.  The INSERT calls are made
   directly by this subroutine, not through lonmysql because we do a 'bulk'
   insert which takes advantage of MySQLs non-SQL compliant INSERT command to 
   insert multiple rows at a time.  If anything has gone wrong during this
   process, $returnstatus is updated with a description of the error and
   \%student_data is returned.  
   
   Notice we do not insert the data and immediately query it.  This means it
   is possible for there to be data returned this first time that is not 
   available the second time.  CYA.
   
   =item &ensure_tables_are_set_up($courseid)
   
   Checks to be sure the MySQL tables for the given class are set up.
   If $courseid is omitted it will be obtained from the environment.
   
   Returns nothing on success and 'error' on failure
   
   
   =item C<&ensure_current_data()>
   
   Input: $sname, $sdom, $courseid
   
   Output: $status, $data
   
 =item &TestCacheData()  This routine ensures the data for a given student is up to date.
   The $student_table is queried to determine the time of the last update.  
   If the students data is out of date, &update_student_data() is called.  
   The return values from the call to &update_student_data() are returned.
   
 Determine if the cache database can be accessed with a tie.  It waits up to  =item C<&ensure_current_full_data($sname,$sdom,$courseid)>
 ten seconds before returning failure.  This function exists to help with  
 the problems with stopping the data download.  When an abort occurs and the  Input: $sname, $sdom, $courseid
 user quickly presses a form button and httpd child is created.  This  
 child needs to wait for the other to finish (hopefully within ten seconds).  Output: $status
   
   This routine ensures the fulldata (the data from a lonnet::dump, not a
   lonnet::currentdump) for a given student is up to date.
   The $student_table is queried to determine the time of the last update.  
   If the students fulldata is out of date, &update_full_student_data() is
   called.  
   
   The return value from the call to &update_full_student_data() is returned.
   
   =item C<&get_student_data_from_performance_cache()>
   
   Input: $sname, $sdom, $symb, $courseid
   
   Output: hash reference containing the data for the given student.
   If $symb is undef, all the students data is returned.
   
   This routine is the heart of the local caching system.  See the description
   of $performance_table, $symb_table, $student_table, and $part_table.  The
   main task is building the MySQL request.  The tables appear in the request
   in the order in which they should be parsed by MySQL.  When searching
   on a student the $student_table is used to locate the 'student_id'.  All
   rows in $performance_table which have a matching 'student_id' are returned,
   with data from $part_table and $symb_table which match the entries in
   $performance_table, 'part_id' and 'symb_id'.  When searching on a symb,
   the $symb_table is processed first, with matching rows grabbed from 
   $performance_table and filled in from $part_table and $student_table in
   that order.  
   
   Running 'EXPLAIN ' on the 'SELECT' statements generated can be quite 
   interesting, especially if you play with the order the tables are listed.  
   
   
   =item C<&get_current_state()>
   
   Input: $sname,$sdom,$symb,$courseid
   
   Output: Described below
   
   Retrieve the current status of a students performance.  $sname and
   $sdom are the only required parameters.  If $symb is undef the results
   of an &Apache::lonnet::currentdump() will be returned.  
   If $courseid is undef it will be retrieved from the environment.
   
   The return structure is based on &Apache::lonnet::currentdump.  If
   $symb is unspecified, all the students data is returned in a hash of
   the form:
   ( 
     symb1 => { param1 => value1, param2 => value2 ... },
     symb2 => { param1 => value1, param2 => value2 ... },
   )
   
   If $symb is specified, a hash of 
   (
     param1 => value1, 
     param2 => value2,
   )
   is returned.
   
   If no data is found for $symb, or if the student has no performance data,
   an empty list is returned.
   
   =item C<&get_problem_statistics()>
   
   Gather data on a given problem.  The database is assumed to be 
   populated and all local caching variables are assumed to be set
   properly.  This means you need to call &ensure_current_data for
   the students you are concerned with prior to calling this routine.
   
   Inputs: $Sections, Groups, $status, $symb, $part, $courseid, $starttime,
           $endtime
   
 =over 4  =over 4
   
 Input: $ChartDB  =item $Sections Array ref containing section names for students.  
   'all' is allowed to be the first (and only) item in the array.
   
   =item $Groups Array ref containing group names for students.
   'all' is allowed to be the first (and only) item in the array.
   
   =item $status String describing the status of students
   
   =item $symb is the symb for the problem.
   
 $ChartDB: The name of the cache database to be opened  =item $part is the part id you need statistics for
   
 Output: -1, 0, 1  =item $courseid is the course id, of course!
   
 -1: Could not tie database  =item $starttime and $endtime are unix times which to use to limit
  0: Use cached data  the statistical data.
  1: New cache database created, use that.  
   
 =back  =back
   
 =cut  Outputs: See the code for up to date information.  A hash reference is
   returned.  The hash has the following keys defined:
   
 sub TestCacheData {  =over 4
     my ($ChartDB,$isRecalculate,$totalDelay)=@_;  
     my $isCached=-1;  
     my %testData;  
     my $tieTries=0;  
   
     if(!defined($totalDelay)) {  =item * num_students 
         $totalDelay = 10;  
     }  
   
     if ((-e "$ChartDB") && (!$isRecalculate)) {  The number of students attempting the problem
  $isCached = 1;        
     } else {  =item tries 
  $isCached = 0;  
     }  
   
     while($tieTries < $totalDelay) {  The total number of tries for the students
         my $result=0;        
         if($isCached) {  =item max_tries 
             $result=tie(%testData,'GDBM_File',$ChartDB,&GDBM_READER(),0640);  
         } else {  
             $result=tie(%testData,'GDBM_File',$ChartDB,&GDBM_NEWDB(),0640);  
         }  
         if($result) {  
             last;  
         }  
         $tieTries++;  
         sleep 1;  
     }  
     if($tieTries >= $totalDelay) {  
         return -1;  
     }  
   
     untie(%testData);  The maximum number of tries taken
         
   =item mean_tries 
   
     return $isCached;  The average number of tries
 }        
   =item num_solved T
   
 sub DownloadStudentCourseData {  he number of students able to solve the problem
     my ($students,$checkDate,$cacheDB,$extract,$status,$courseID,$r,$c)=@_;        
   =item num_override 
   
     my $title = 'LON-CAPA Statistics';  The number of students whose answer is 'correct_by_override'
     my $heading = 'Download and Process Course Data';        
     my $studentCount = scalar(@$students);  =item deg_of_diff 
   
     my $WhatIWant;  The degree of difficulty of the problem
     $WhatIWant = '(^version:|';        
     $WhatIWant .= '^\d+:.+?:(resource\.\d+\.';  =item std_tries 
     $WhatIWant .= '(solved|tries|previous|awarded|(\d+\.submission))\s*$';  
     $WhatIWant .= '|timestamp)';  
     $WhatIWant .= ')';  
 #    $WhatIWant = '.';  
   
     if($status eq 'true') {  The standard deviation of the number of tries
         &Apache::lonhtmlcommon::Create_PrgWin($r, $title, $heading);        
     }  =item skew_tries 
   
     my $displayString;  The skew of the number of tries
     my $count=0;  
     foreach (@$students) {  
         my %cache;  
   
         if($c->aborted()) { return 'Aborted'; }  =item per_wrong 
   
         if($status eq 'true') {  The number of students attempting the problem who were not
             $count++;  able to answer it correctly.
             my $displayString = $count.'/'.$studentCount.': '.$_;  
             &Apache::lonhtmlcommon::Update_PrgWin($displayString, $r);  
         }  
   
         my $downloadTime='Not downloaded';  =back
         my $needUpdate = 'false';  
         if($checkDate eq 'true'  &&   
            tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {  
             $downloadTime = $cache{$_.':lastDownloadTime'};  
             $needUpdate = $cache{'ResourceUpdated'};  
             untie(%cache);  
         }  
   
         if($c->aborted()) { return 'Aborted'; }  =item C<&populate_weight_table()>
   
         if($needUpdate eq 'true') {  =item C<&limit_by_start_end_times()>
             $downloadTime = 'Not downloaded';  
  }  
  my $courseData =   
     &DownloadCourseInformation($_, $courseID, $downloadTime,   
        $WhatIWant);  
  if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {  
     foreach my $key (keys(%$courseData)) {  
  if($key =~ /^(con_lost|error|no_such_host)/i) {  
     $courseData->{$_.':error'} = 'No course data for '.$_;  
     last;  
  }  
     }  
     if($extract eq 'true') {  
  &ExtractStudentData($courseData, \%cache, \%cache, $_);  
     } else {  
  &ProcessStudentData(\%cache, $courseData, $_);  
     }  
     untie(%cache);  
  } else {  
     next;  
  }  
     }  
     if($status eq 'true') { &Apache::lonhtmlcommon::Close_PrgWin($r); }  
   
     return 'OK';  Build SQL WHERE condition which limits the data collected by the start
 }  and end times provided
   
 sub DownloadStudentCourseDataSeparate {  Inputs: $starttime, $endtime, $table
     my ($students,$checkDate,$cacheDB,$extract,$status,$courseID,$r,$c)=@_;  
     my $residualFile = '/home/httpd/perl/tmp/'.$courseID.'DownloadFile.db';  
     my $title = 'LON-CAPA Statistics';  
     my $heading = 'Download Course Data';  
   
     my $WhatIWant;  Returns: $time_limits
     $WhatIWant = '(^version:|';  
     $WhatIWant .= '^\d+:.+?:(resource\.\d+\.';  
     $WhatIWant .= '(solved|tries|previous|awarded|(\d+\.submission))\s*$';  
     $WhatIWant .= '|timestamp)';  
     $WhatIWant .= ')';  
   
     &CheckForResidualDownload($cacheDB, 'true', 'true', $courseID, $r, $c);  
   
     my $studentCount = scalar(@$students);  =item C<&limit_by_section_and_status()C>
     if($status eq 'true') {  
         &Apache::lonhtmlcommon::Create_PrgWin($r, $title, $heading);  
     }  
     my $count=0;  
     my $displayString='';  
     foreach (@$students) {  
         if($c->aborted()) {  
             return 'Aborted';  
         }  
   
         if($status eq 'true') {  Build SQL WHERE condition which limits the data collected by section and
             $count++;  student status.
             $displayString = $count.'/'.$studentCount.': '.$_;  
             &Apache::lonhtmlcommon::Update_PrgWin($displayString, $r);  
         }  
   
         my %cache;  Inputs: $Sections (array ref)
         my $downloadTime='Not downloaded';      $enrollment (string: 'any', 'expired', 'active')
         my $needUpdate = 'false';      $tablename The name of the table that holds the student data
         if($checkDate eq 'true'  &&   
            tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {  
             $downloadTime = $cache{$_.':lastDownloadTime'};  
             $needUpdate = $cache{'ResourceUpdated'};  
             untie(%cache);  
         }  
   
         if($c->aborted()) {  Returns: $student_requirements,$enrollment_requirements
             return 'Aborted';  
         }  
   
         if($needUpdate eq 'true') {  =item C<&limit_by_group()>
             $downloadTime = 'Not downloaded';                                                                                 
  }  Build SQL LEFT JOIN statement to include students_groups and groupnames tables and SQL WHERE condition which limits the data collected by group.
                                                                                  
   Inputs: $Groups (array ref)
       $stutable   The name of the table which holds the student data.
       $grptable   The name of the table which maps group_id to groupname.
       $stugrptab  The name of the table which holds student group affiliations.   
   Returns: $groups_join,$group_limits
      $groups_join  JOIN part of SQL statement (to include group related tables) 
      $group_limits SQL WHERE condition limiting to requested groups
   
         my $error = 0;  =item C<rank_students_by_scores_on_resources()>
         my $courseData =   
             &DownloadCourseInformation($_, $courseID, $downloadTime,  
                                        $WhatIWant);  
         my %downloadData;  
         unless(tie(%downloadData,'GDBM_File',$residualFile,  
                    &GDBM_WRCREAT(),0640)) {  
             return 'Failed to tie temporary download hash.';  
         }  
         foreach my $key (keys(%$courseData)) {  
             $downloadData{$key} = $courseData->{$key};  
             if($key =~ /^(con_lost|error|no_such_host)/i) {  
                 $error = 1;  
                 last;  
             }  
         }  
         if($error) {  
             foreach my $deleteKey (keys(%$courseData)) {  
                 delete $downloadData{$deleteKey};  
             }  
             $downloadData{$_.':error'} = 'No course data for '.$_;  
         }  
         untie(%downloadData);  
     }  
     if($status eq 'true') { &Apache::lonhtmlcommon::Close_PrgWin($r); }  
   
     return &CheckForResidualDownload($cacheDB, 'true', 'true',   Inputs: 
                                      $courseID, $r, $c);      $resources: array ref of hash ref.  Each hash ref needs key 'symb'.
 }      $Sections: array ref of sections to include,
       $Groups: array ref of groups to include.
       $enrollment: string,
       $courseid (may be omitted)
       $starttime (may be omitted)
       $endtime (may be omitted)
       $has_award_for (may be omitted)
   
 sub CheckForResidualDownload {  Returns; An array of arrays.  The sub arrays contain a student name and
     my ($cacheDB,$extract,$status,$courseID,$r,$c)=@_;  their score on the resources. $starttime and $endtime constrain the
   list to awards obtained during the given time limits. $has_score_on
   constrains the list to those students who at least attempted the
   resource identified by the given symb, which is used to filter out
   such students for statistics that would be adversely affected by such
   students.
   
     my $residualFile = '/home/httpd/perl/tmp/'.$courseID.'DownloadFile.db';  =item C<&get_sum_of_scores>
     if(!-e $residualFile) {  
         return 'OK';  
     }  
   
     my %downloadData;  Inputs: $resource (hash ref, needs {'symb'} key),
     my %cache;  $part, (the part id),
     unless(tie(%downloadData,'GDBM_File',$residualFile,&GDBM_READER(),0640)) {  $students (array ref, contents of array are scalars holding 'sname:sdom'),
         return 'Can not tie database for check for residual download: tempDB';  $courseid
     }  
     unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {  
         untie(%downloadData);  
         return 'Can not tie database for check for residual download: cacheDB';  
     }  
   
     my @students=();  Returns: the sum of the score on the problem part over the students and the
     my %checkStudent;     maximum possible value for the sum (taken from the weight table).
     my $key;   
     while(($key, undef) = each %downloadData) {  
         my @temp = split(':', $key);  
         my $student = $temp[0].':'.$temp[1];  
         if(!defined($checkStudent{$student})) {  
             $checkStudent{$student}++;  
             push(@students, $student);  
         }  
     }  
   
     my $heading = 'Process Course Data';  =item C<&score_stats()>
     my $title = 'LON-CAPA Statistics';  
     my $studentCount = scalar(@students);  
     if($status eq 'true') {  
         &Apache::lonhtmlcommon::Create_PrgWin($r, $title, $heading);  
     }  
   
     my $count=1;  Inputs: $Sections, $enrollment, $symbs, $starttime,
     foreach my $name (@students) {          $endtime, $courseid
         last if($c->aborted());  
   
         if($status eq 'true') {  $Sections, $enrollment, $starttime, $endtime, and $courseid are the same as 
             my $displayString = $count.'/'.$studentCount.': '.$name;  elsewhere in this module.  
             &Apache::lonhtmlcommon::Update_PrgWin($displayString, $r);  $symbs is an array ref of symbs
         }  
   
         if($extract eq 'true') {  Returns: minimum, maximum, mean, s.d., number of students, and maximum
             &ExtractStudentData(\%downloadData, \%cache, \%cache, $name);    possible of student scores on the given resources
         } else {  
             &ProcessStudentData(\%cache, \%downloadData, $name);  
         }  
         $count++;  
     }  
   
     if($status eq 'true') { &Apache::lonhtmlcommon::Close_PrgWin($r); }  =item C<&count_stats()>
   
     untie(%cache);  Inputs: $Sections, $Groups, $enrollment, $symbs, $starttime,
     untie(%downloadData);          $endtime, $courseid
   
     if(!$c->aborted()) {  $Sections, $Groups $enrollment, $starttime, $endtime, and $courseid are the 
         my @files = ($residualFile);  same as elsewhere in this module.  
         unlink(@files);  $symbs is an array ref of symbs
     }  
   
     return 'OK';  Returns: minimum, maximum, mean, s.d., and number of students
 }    of the number of items correct on the given resources
   
   =item C<get_student_data()>
   
   =item C<&get_student_scores($Sections,$Groups,$Symbs,$enrollment,$courseid)>
   
   =item C<&setup_table_names()>
   
   input: course id
   
   output: none
   
   =back
   
   =head3 End of Local Data Caching Subroutines
   
   =head3 Classlist Subroutines
   
   =over
   
   =item &get_classlist();
   
   Retrieve the classist of a given class or of the current class.  Student
   information is returned from the classlist.db file and, if needed,
   from the students environment.
   
   Optional arguments are $cdom, and $cnum (course domain,
   and course number, respectively).  If either is ommitted the course
   will be taken from the current environment ($env{'request.course.id'},
   $env{'course.'.$cid.'.domain'}, and $env{'course.'.$cid.'.num'}).
   
   Returns a reference to a hash which contains:
    keys    '$sname:$sdom'
    values  [$sdom,$sname,$end,$start,$id,$section,$fullname,$status,$type,
             $lockedtype,$credits,$instsec]
   
   The constant values CL_SDOM, CL_SNAME, CL_END, etc. can be used
   as indices into the returned list to future-proof clients against
   changes in the list order.
   
   =back
   
   =cut
   
 # ----- END HELPER FUNCTIONS --------------------------------------------  
   
 1;  
 __END__  

Removed from v.1.34  
changed lines
  Added in v.1.201.2.3


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