Diff for /loncom/interface/loncoursedata.pm between versions 1.5 and 1.170

version 1.5, 2002/07/25 19:31:32 version 1.170, 2006/05/11 20:05:03
Line 1 Line 1
 # The LearningOnline Network with CAPA  # The LearningOnline Network with CAPA
 # (Publication Handler  
 #  #
 # $Id$  # $Id$
 #  #
Line 35  loncoursedata Line 34  loncoursedata
   
 =head1 SYNOPSIS  =head1 SYNOPSIS
   
 Set of functions that download and process student information.  Set of functions that download and process student and course information.
   
 =head1 PACKAGES USED  =head1 PACKAGES USED
   
  Apache::Constants qw(:common :http)   Apache::Constants qw(:common :http)
  Apache::lonnet()   Apache::lonnet()
    Apache::lonhtmlcommon
  HTML::TokeParser   HTML::TokeParser
  GDBM_File   GDBM_File
   
Line 49  Set of functions that download and proce Line 49  Set of functions that download and proce
 package Apache::loncoursedata;  package Apache::loncoursedata;
   
 use strict;  use strict;
 use Apache::Constants qw(:common :http);  use Apache::lonnet;
 use Apache::lonnet();  use Apache::lonhtmlcommon;
   use Time::HiRes;
   use Apache::lonmysql;
 use HTML::TokeParser;  use HTML::TokeParser;
 use GDBM_File;  use GDBM_File;
   
Line 58  use GDBM_File; Line 60  use GDBM_File;
   
 =head1 DOWNLOAD INFORMATION  =head1 DOWNLOAD INFORMATION
   
 This section contains all the files that get data from other servers   This section contains all the functions that get data from other servers 
 and/or itself.  There is one function that has a call to get remote  and/or itself.
 information but isn't included here which is ProcessTopLevelMap.  The  
 usage was small enough to be ignored, but that portion may be moved  
 here in the future.  
   
 =cut  =cut
   
 # ----- DOWNLOAD INFORMATION -------------------------------------------  ################################################
   ################################################
   
 =pod  =pod
   
 =item &DownloadClasslist()  =item &make_into_hash($values);
   
 Collects lastname, generation, middlename, firstname, PID, and section for each  Returns a reference to a hash as described by $values.  $values is
 student from their environment database.  The list of students is built from  assumed to be the result of 
 collecting a classlist for the course that is to be displayed.      join(':',map {&Apache::lonnet::escape($_)} %orighash);
   
   This is a helper function for get_current_state.
   
   =cut
   
   ################################################
   ################################################
   sub make_into_hash {
       my $values = shift;
       my %tmp = map { &Apache::lonnet::unescape($_); }
                                              split(':',$values);
       return \%tmp;
   }
   
   
   ################################################
   ################################################
   
   =pod
   
   =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.
   
   Some notes before we get started.
   
   Each table must have a PRIMARY KEY, which is a column or set of columns which
   will serve to uniquely identify a row of data.  NULL is not allowed!
   
   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.
   
   =head3 Table Descriptions
   
 =over 4  =over 4
   
 Input: $courseID, $c  =item Tables used to store meta information
   
   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.
   
   =over 4
   
   =item $symb_table
   
   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'.
   
   =item $part_table
   
   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'.
   
 $courseID:  The id of the course  =item $student_table
   
 $c: The connection class that can determine if the browser has aborted.  It  The student_table has 7 columns.  The first is a 'student_id' assigned by 
 is used to short circuit this function so that it doesn't continue to   MySQL.  The second is 'student' which is username:domain.  The third through
 get information when there is no need.  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'.
   
 Output: \%classlist  =item $groupnames_table
   
 \%classlist: A pointer to a hash containing the following data:  The groupnames_table has 2 columns.  The first is a 'group_id' assigned by 
   MySQL.  The second is 'groupname' which is the name of the group in the course.
   
 -A list of student name:domain (as keys) (known below as $name)  =item $students_groups_table
   
 -A hash pointer for each student containing lastname, generation, firstname,  The students_groups_table has 2 columns.  The first is the 'student_id', and the 
 middlename, and PID : Key is $name.'studentInformation'  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.
   
 -A hash pointer to each students section data : Key is $name.section  =back 
   
   =item 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 $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 $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  =back
   
   =item Tables used for storing historic data
   
   The following tables are used to store almost all of the transactions a student
   has made on a homework problem.  See loncapa/docs/homework/datastorage for 
   specific information about each of the parameters stored.  
   
   =over 4
   
   =item $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 $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 $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 $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
   
   =back
   
   =head3 Important Subroutines
   
   Here is a brief overview of the subroutines which are likely to be of 
   interest:
   
   =over 4
   
   =item &get_current_state(): programmers interface.
   
   =item &init_dbs(): table creation
   
   =item &update_student_data(): data storage calls
   
   =item &get_student_data_from_performance_cache(): data retrieval
   
   =back
   
   =head3 Main Documentation
   
   =over 4
   
 =cut  =cut
   
 sub DownloadClasslist {  ################################################
     my ($courseID, $lastDownloadTime, $c)=@_;  ################################################
     my ($courseDomain,$courseNumber)=split(/\_/,$courseID);  
     my %classlist;  
   
 #    my $modifiedTime = &GetFileTimestamp($courseDomain, $courseNumber,  
 #                                     'classlist.db',   
 #                                     $Apache::lonnet::perlvar{'lonUsersDir'});  
   
 #    if($lastDownloadTime ne 'Not downloaded' &&  
 #       $lastDownloadTime >= $modifiedTime && $modifiedTime >= 0) {  
 #        $classlist{'lastDownloadTime'}=time;  
 #        $classlist{'UpToDate'} = 'true';  
 #        return \%classlist;  
 #    }  
   
     %classlist=&Apache::lonnet::dump('classlist',$courseDomain, $courseNumber);  ################################################
     my ($checkForError)=keys (%classlist);  ################################################
     if($checkForError =~ /^(con_lost|error|no_such_host)/i) {  { # Begin scope of table identifiers
         return \%classlist;  
     }  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;
   ################################################
   ################################################
   
     foreach my $name (keys(%classlist)) {  =pod
         if($c->aborted()) {  
             $classlist{'error'}='aborted';  
             return \%classlist;  
         }  
   
         my ($studentName,$studentDomain) = split(/\:/,$name);  =item &init_dbs()
         # Download student environment data, specifically the full name and id.  
         my %studentInformation=&Apache::lonnet::get('environment',  
                                                     ['lastname','generation',  
                                                      'firstname','middlename',  
                                                      'id'],  
                                                     $studentDomain,  
                                                     $studentName);  
         $classlist{$name.':studentInformation'}=\%studentInformation;  
   
         if($c->aborted()) {  Input: course id
             $classlist{'error'}='aborted';  
             return \%classlist;  
         }  
   
         #Section  Output: 0 on success, positive integer on error
         my %section=&Apache::lonnet::dump('roles',$studentDomain,$studentName);  
         $classlist{$name.':sections'}=\%section;  This routine issues the calls to lonmysql to create the tables used to
     }  store student data.
   
     $classlist{'UpToDate'} = 'false';  =cut
     $classlist{'lastDownloadTime'}=time;  
   
     return \%classlist;  ################################################
   ################################################
   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 => 'status',
                         type => 'VARCHAR(15) BINARY',
                         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)',
                                   'status (15)',]},],
       };
       #
       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 &DownloadCourseInformation()  =item &delete_caches()
   
 Dump of all the course information for a single student.  There is no  This routine drops all the tables associated with a course from the 
 pruning of data, it is all stored in a hash and returned.  It also  MySQL database.
 checks the timestamp of the students course database file and only downloads  
 if it has been modified since the last download.  
   
 =over 4  Input: course id (optional, determined by environment if omitted) 
   
   Returns: nothing
   
   =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;
   }
   
 Input: $name, $courseID  ################################################
   ################################################
   
 $name: student name:domain  =pod
   
 $courseID:  The id of the course  =item &get_part_id()
   
 Output: \%courseData  Get the MySQL id of a problem part string.
   
 \%courseData:  A hash pointer to the raw data from the student's course  Input: $part
 database.  
   
 =back  Output: undef on error, integer $part_id on success.
   
   =item &get_part()
   
   Get the string describing a part from the MySQL id of the problem part.
   
   Input: $part_id
   
   Output: undef on error, $part string on success.
   
 =cut  =cut
   
 sub DownloadCourseInformation {  ################################################
     my ($namedata,$courseID,$lastDownloadTime)=@_;  ################################################
     my %courseData;  
     my ($name,$domain) = split(/\:/,$namedata);  
   
 #    my $modifiedTime = &GetFileTimestamp($domain, $name,  
 #                                      $courseID.'.db',   
 #                                      $Apache::lonnet::perlvar{'lonUsersDir'});  
 #    if($lastDownloadTime >= $modifiedTime) {  
 #        $courseData{'lastDownloadTime'}=time;  
 #        $courseData{'UpToDate'} = 'true';  
 #        return \%courseData;  
 #    }  
   
     # Download course data  my $have_read_part_table = 0;
     %courseData=&Apache::lonnet::dump($courseID, $domain, $name);  my %ids_by_part;
     $courseData{'UpToDate'} = 'false';  my %parts_by_id;
     $courseData{'lastDownloadTime'}=time;  
     return \%courseData;  sub get_part_id {
       my ($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
 }  }
   
 # ----- END DOWNLOAD INFORMATION ---------------------------------------  sub get_part {
       my ($part_id) = @_;
       if (! exists($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
   }
   
   ################################################
   ################################################
   
 =pod  =pod
   
 =head1 PROCESSING FUNCTIONS  =item &get_symb_id()
   
   Get the MySQL id of a symb.
   
   Input: $symb
   
   Output: undef on error, integer $symb_id on success.
   
   =item &get_symb()
   
 These functions process all the data for all the students.  Also, they  Get the symb associated with a MySQL symb_id.
 are the only functions that access the cache database for writing.  Thus  
 they are the only functions that cache data.  The downloading and caching  Input: $symb_id
 were separated to reduce problems with stopping downloading then can't  
 tie hash to database later.  Output: undef on error, $symb on success.
   
 =cut  =cut
   
 # ----- PROCESSING FUNCTIONS ---------------------------------------  ################################################
   ################################################
   
   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
   }
   
   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
   }
   
   ################################################
   ################################################
   
 =pod  =pod
   
 =item &ProcessTopResourceMap()  =item &get_student_id()
   
 Trace through the "big hash" created in rat/lonuserstate.pm::loadmap.    Get the MySQL id of a student.
 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  Input: $sname, $dom
   
 Input: $cache, $c  Output: undef on error, integer $student_id on success.
   
 $cache:  A pointer to a hash to store the information  =item &get_student()
   
 $c:  The connection class used to determine if an abort has been sent to the   Get student username:domain associated with the MySQL student_id.
 browser  
   
 Output: A string that contains an error message or "OK" if everything went   Input: $student_id
 smoothly.  
   
 =back  Output: undef on error, string $student (username:domain) on success.
   
 =cut  =cut
   
 sub ProcessTopResourceMap {  ################################################
     my ($cache,$c)=@_;  ################################################
     my %hash;  
     my $fn=$ENV{'request.course.fn'};  my $have_read_student_table = 0;
     if(-e "$fn.db") {  my %ids_by_student;
  my $tieTries=0;  my %students_by_id;
  while($tieTries < 3) {  
             if($c->aborted()) {  sub get_student_id {
                 return;      my ($sname,$sdom) = @_;
             }      my $student = $sname.':'.$sdom;
     if(tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) {      if (! $have_read_student_table) {
  last;          my @Result = &Apache::lonmysql::get_rows($student_table);
     }          foreach (@Result) {
     $tieTries++;              $ids_by_student{$_->[1]}=$_->[0];
     sleep 1;          }
  }          $have_read_student_table = 1;
  if($tieTries >= 3) {      }
             return 'Coursemap undefined.';      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];
         }          }
     } else {  
         return 'Can not open Coursemap.';  
     }      }
       return $ids_by_student{$student} if(exists( $ids_by_student{$student}));
       return undef; # error
   }
   
     # Initialize state machine.  Set information pointing to top level map.  sub get_student {
     my (@sequences, @currentResource, @finishResource);      my ($student_id) = @_;
     my ($currentSequence, $currentResourceID, $lastResourceID);      if (! exists($students_by_id{$student_id})  || 
           ! defined($students_by_id{$student_id}) ||
     $currentResourceID=$hash{'ids_/res/'.$ENV{'request.course.uri'}};          $students_by_id{$student_id} eq '') {
     push(@currentResource, $currentResourceID);          my @Result = &Apache::lonmysql::get_rows($student_table);
     $lastResourceID=-1;          foreach (@Result) {
     $currentSequence=-1;              $students_by_id{$_->[0]}=$_->[1];
     my $topLevelSequenceNumber = $currentSequence;          }
       }
     while(1) {      return $students_by_id{$student_id} if(exists($students_by_id{$student_id}));
         if($c->aborted()) {      return undef; # error
             last;  }
         }  
  # HANDLE NEW SEQUENCE!  
  #if page || sequence  
  if(defined($hash{'map_pc_'.$hash{'src_'.$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;  
             }  
   
     $lastResourceID=$hash{'map_finish_'.  sub populate_student_table {
   $hash{'src_'.$currentResourceID}};      my ($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);
  $currentResourceID=pop(@currentResource);      &init_dbs($courseid,0);
  $lastResourceID=pop(@finishResource);      my $dbh = &Apache::lonmysql::get_dbh();
  if($currentSequence eq $topLevelSequenceNumber) {      my $request = 'INSERT IGNORE INTO '.$student_table.
     last;          "(student,section,status) 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 ($section,$status) = ($data->[&CL_SECTION()],
                                    $data->[&CL_STATUS()]);
           if ($section eq '' || $section =~ /^\s*$/) {
               $section = 'none';
           }
           $request .= "('".$student."','".$section."','".$status."'),";
           $student_count++;
       }
       return if ($student_count == 0);
       chop($request);
       $dbh->do($request);
       if ($dbh->err()) {
           &Apache::lonnet::logthis("error ".$dbh->errstr().
                                    " occured executing \n".
                                    $request);
       }
       return;
   }
   
  # Handle gradable resources: exams, problems, etc  my $have_read_groupnames_table = 0;
  $currentResourceID=~/(\d+)\.(\d+)/;  my %ids_by_groupname;
         my $partA=$1;  
         my $partB=$2;  
  if($hash{'src_'.$currentResourceID}=~  
    /\.(problem|exam|quiz|assess|survey|form)$/ &&  
    $partA eq $currentSequence) {  
     my $Problem = &Apache::lonnet::symbclean(  
   &Apache::lonnet::declutter($hash{'map_id_'.$partA}).  
   '___'.$partB.'___'.  
   &Apache::lonnet::declutter($hash{'src_'.  
  $currentResourceID}));  
   
     $cache->{$currentResourceID.':problem'}=$Problem;  
     if(!defined($cache->{$currentSequence.':problems'})) {  
  $cache->{$currentSequence.':problems'}=$currentResourceID;  
     } else {  
  $cache->{$currentSequence.':problems'}.=  
     ':'.$currentResourceID;  
     }  
   
     my $meta=$hash{'src_'.$currentResourceID};  sub get_group_id {
 #            $cache->{$currentResourceID.':title'}=      my ($groupname) = @_;
 #                &Apache::lonnet::metdata($meta,'title');      if (! $have_read_groupnames_table) {
             $cache->{$currentResourceID.':title'}=          my @Result = &Apache::lonmysql::get_rows($groupnames_table);
                 $hash{'title_'.$currentResourceID};          foreach (@Result) {
               $ids_by_groupname{$_->[1]}=$_->[0];
             # Get Parts for problem          }
     foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {          $have_read_groupnames_table = 1;
  if($_=~/^stores\_(\d+)\_tries$/) {      }
     my $Part=&Apache::lonnet::metadata($meta,$_.'.part');      if (! exists($ids_by_groupname{$groupname})) {
                     if(!defined($cache->{$currentSequence.':'.          &populate_groupnames_table();
                                           $currentResourceID.':parts'})) {          undef(%ids_by_groupname);
                         $cache->{$currentSequence.':'.$currentResourceID.          my @Result = &Apache::lonmysql::get_rows($groupnames_table);
                                    ':parts'}=$Part;          foreach (@Result) {
                     } else {              $ids_by_groupname{$_->[1]}=$_->[0];
                         $cache->{$currentSequence.':'.$currentResourceID.          }
                                    ':parts'}.=':'.$Part;      }
                     }      if (exists($ids_by_groupname{$groupname})) {
                     foreach (split(/\,/,          return $ids_by_groupname{$groupname};
                              &Apache::lonnet::metadata($meta,'packages'))) {      }
                         if($_=~/^optionresponse\_($Part)\_(\w+)$/) {      return undef; # error
                             if(defined($cache->{'OptionResponses'})) {  }
                                 $cache->{'OptionResponses'}.= ':::'.  
                                     $hash{'src_'.$currentResourceID}.'::'.  
                                     $hash{'title_'.$currentResourceID}.'::'.  
                                     $Part.'::'.$Problem;  
                             } else {  
                                 $cache->{'OptionResponses'}=  
                                     $hash{'src_'.$currentResourceID}.'::'.  
                                     $hash{'title_'.$currentResourceID}.'::'.  
                                     $Part.'::'.$Problem;  
                             }  
                         }  
                     }  
                 }  
     }  
  }  
   
  # if resource == finish resource, then it is the end of a sequence/page  sub populate_groupnames_table {
  if($currentResourceID eq $lastResourceID) {      my ($courseid) = @_;
     # pop off last resource of sequence      if (! defined($courseid)) {
     $currentResourceID=pop(@currentResource);          $courseid = $env{'request.course.id'};
     $lastResourceID=pop(@finishResource);      }
       &setup_table_names($courseid);
     if(defined($cache->{$currentSequence.':problems'})) {      &init_dbs($courseid,0);
  # Capture sequence information here      my $dbh = &Apache::lonmysql::get_dbh();
  $cache->{$currentSequence.':title'}=      my $cdom = $env{'course.'.$courseid.'.domain'};
     $hash{'title_'.$currentResourceID};      my $cnum = $env{'course.'.$courseid.'.num'};
                 $cache->{$currentSequence.':source'}=      my %curr_groups = &Apache::loncommon::coursegroups($cdom,$cnum);
                     $hash{'src_'.$currentResourceID};      return if (!%curr_groups);
       my $request = 'INSERT IGNORE INTO '.$groupnames_table.
                 my $totalProblems=0;                    '(groupname) VALUES ';
                 foreach my $currentProblem (split(/\:/,      foreach my $groupname (sort(keys(%curr_groups)),'none') {
                                                $cache->{$currentSequence.          $request .= "('".$groupname."'),";
                                                ':problems'})) {      }
                     foreach (split(/\:/,$cache->{$currentSequence.':'.      chop($request);
                                                    $currentProblem.      $dbh->do($request);
                                                    ':parts'})) {      if ($dbh->err()) {
                         $totalProblems++;          &Apache::lonnet::logthis("error ".$dbh->errstr().
                     }                                   " occured executing \n".
                 }                                   $request);
  my @titleLength=split(//,$cache->{$currentSequence.      }
                                                     ':title'});      return;
                 # $extra is 3 for problems correct and 3 for space  }
                 # between problems correct and problem output  
                 my $extra = 6;  
  if(($totalProblems + $extra) > (scalar @titleLength)) {  
     $cache->{$currentSequence.':columnWidth'}=  
                         $totalProblems + $extra;  
  } else {  
     $cache->{$currentSequence.':columnWidth'}=  
                         (scalar @titleLength);  
  }  
     } else {  
                 # Remove sequence from list, if it contains no problems to  
                 # display.  
                 $cache->{'orderedSequences'}=~s/$currentSequence//;  
                 $cache->{'orderedSequences'}=~s/::/:/g;  
                 $cache->{'orderedSequences'}=~s/^:|:$//g;  
             }  
   
     $currentSequence=pop(@sequences);  my $have_read_studentsgroups_table = 0;
     if($currentSequence eq $topLevelSequenceNumber) {  my %groupids_by_studentid;
  last;  
     }  
  }  
   
  # MOVE!!!  sub get_students_groupids {
  # move to next resource      my ($student_id) = @_;
  unless(defined($hash{'to_'.$currentResourceID})) {      if (! $have_read_studentsgroups_table) {
     # big problem, need to handle.  Next is probably wrong          my @Result = &Apache::lonmysql::get_rows($students_groups_table);
     last;          foreach (@Result) {
  }              push(@{$groupids_by_studentid{$_->[0]}},$_->[1]);
  my @nextResources=();          }
  foreach (split(/\,/,$hash{'to_'.$currentResourceID})) {          $have_read_studentsgroups_table = 1;
     push(@nextResources, $hash{'goesto_'.$_});  
  }  
  push(@currentResource, @nextResources);  
  # Set the next resource to be processed  
  $currentResourceID=pop(@currentResource);  
     }      }
       if (! exists($groupids_by_studentid{$student_id})) {
     unless (untie(%hash)) {          &populate_students_groups_table();
         &Apache::lonnet::logthis("<font color=blue>WARNING: ".          undef(%groupids_by_studentid);
                                  "Could not untie coursemap $fn (browse)".          my @Result = &Apache::lonmysql::get_rows($students_groups_table);
                                  ".</font>");           foreach (@Result) {
               push(@{$groupids_by_studentid{$_->[0]}},$_->[1]);
           }
     }      }
       if (exists($groupids_by_studentid{$student_id})) {
           if (ref($groupids_by_studentid{$student_id}) eq 'ARRAY') {
               return @{$groupids_by_studentid{$student_id}};
           }
       }
       return undef; # error
   }
   
     return 'OK';  
   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().
                                    " occured executing \n".
                                    $request);
       }
       return;
 }  }
   
   ################################################
   ################################################
   
 =pod  =pod
   
 =item &ProcessClasslist()  =item &clear_internal_caches()
   
 Taking the class list dumped from &DownloadClasslist(), all the   Causes the internal caches used in get_student_id, get_student,
 students and their non-class information is processed using the   get_symb_id, get_symb, get_part_id, and get_part to be undef'd.
 &ProcessStudentInformation() function.  A date stamp is also recorded for  
 when the data was processed.  
   
 Takes data downloaded for a student and breaks it up into managable pieces and   Needs to be called before the first operation with the MySQL database
 stored in cache data.  The username, domain, class related date, PID,   for a given Apache request.
 full name, and section are all processed here.  
   
   =cut
   
 =over 4  ################################################
   ################################################
   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);
   }
   
 Input: $cache, $classlist, $courseID, $ChartDB, $c  
   
 $cache: A hash pointer to store the data  ################################################
   ################################################
   
 $classlist:  The hash of data collected about a student from   sub symb_is_for_task {
 &DownloadClasslist().  The hash contains a list of students, a pointer       my ($symb) = @_;
 to a hash of student information for each student, and each student's section       return ($symb =~ /\.task$/);
 number.  }
   
 $courseID:  The course ID  ################################################
   ################################################
   
 $ChartDB:  The name of the cache database file.  =pod
   
 $c:  The connection class used to determine if an abort has been sent to the   =item &update_full_student_data($sname,$sdom,$courseid)
 browser  
   
 Output: @names  Does a lonnet::dump on a student to populate the courses tables.
   
 @names:  An array of students whose information has been processed, and are to   Input: $sname, $sdom, $courseid
 be considered in an arbitrary order.  
   
 =back  Output: $returnstatus
   
   $returnstatus is a string describing any errors that occured.  '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 occured 
   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.
   
 =cut  =cut
   
 sub ProcessClasslist {  ################################################
     my ($cache,$classlist,$courseID,$c)=@_;  ################################################
     my @names=();  sub update_full_student_data {
       my ($sname,$sdom,$courseid) = @_;
     $cache->{'ClasslistTimeStamp'}=$classlist->{'lastDownloadTime'};      #
     if($classlist->{'UpToDate'} eq 'true') {      # Set up database names
         return split(/:::/,$cache->{'NamesOfStudents'});;      &setup_table_names($courseid);
       #
       my $student_id = &get_student_id($sname,$sdom);
       my @group_ids = &get_students_groupids($student_id);
       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;
     foreach my $name (keys(%$classlist)) {      #
         if($name =~ /\:section/ || $name =~ /\:studentInformation/ ||      # Get database handle and clean out the tables 
            $name eq '' || $name eq 'UpToDate' || $name eq 'lastDownloadTime') {      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);
           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;              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}=$value;
                   }
               }
         }          }
         if($c->aborted()) {      }
             return ();      ##
       ## 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) {
               $returnstatus = 'error storing part data';
               &Apache::lonnet::logthis('insert error '.$dbh->errstr());
               &Apache::lonnet::logthis("While attempting\n".$store_command);
         }          }
         push(@names,$name);      }
         my $studentInformation = $classlist->{$name.':studentInformation'},      ##
         my $sectionData = $classlist->{$name.':sections'},      ## Store the response data
         my $date = $classlist->{$name},      $store_command = 'INSERT IGNORE INTO '.$fulldump_response_table.
         my ($studentName,$studentDomain) = split(/\:/,$name);          ' VALUES '."\n";
       $store_rows = 0;
         $cache->{$name.':username'}=$studentName;      while (my ($symb_id,$hash1) = each (%$respdata)) {
         $cache->{$name.':domain'}=$studentDomain;          while (my ($part_id,$hash2) = each (%$hash1)) {
         if(!defined($cache->{$name.':lastDownloadTime'})) {              while (my ($resp_id,$hash3) = each (%$hash2)) {
             $cache->{$name.':lastDownloadTime'}='Not downloaded';                  while (my ($transaction,$data) = each (%$hash3)) {
         }                      my $submission = $data->{'submission'};
                       # We have to be careful with user supplied input.
         my ($checkForError)=keys(%$studentInformation);                      # most of the time we are okay because it is escaped.
         if($checkForError =~ /^(con_lost|error|no_such_host)/i) {                      # However, there is one wrinkle: submissions which end in
             $cache->{$name.':error'}=                      # and odd number of '\' cause insert errors to occur.  
                 'Could not download student environment data.';                      # Best trap this somehow...
             $cache->{$name.':fullname'}='';                      $submission = $dbh->quote($submission);
             $cache->{$name.':id'}='';                      $store_command .= "('".
         } else {                          join("','",$symb_id,$part_id,
             $cache->{$name.':fullname'}=&ProcessFullName(                               $resp_id,$student_id,
                                           $studentInformation->{'lastname'},                               $transaction,
                                           $studentInformation->{'generation'},                               $data->{'awarddetail'},
                                           $studentInformation->{'firstname'},                               $data->{'response_specific'},
                                           $studentInformation->{'middlename'});                               $data->{'response_specific_value'},
             $cache->{$name.':id'}=$studentInformation->{'id'};                               $data->{'response_specific_2'},
         }                               $data->{'response_specific_value_2'}).
                                "',".$submission."),";
         my ($end, $start)=split(':',$date);                      $store_rows++;
         $courseID=~s/\_/\//g;  
         $courseID=~s/^(\w)/\/$1/;  
   
         my $sec='';  
         foreach my $key (keys (%$sectionData)) {  
             my $value = $sectionData->{$key};  
             if ($key=~/^$courseID(?:\/)*(\w+)*\_st$/) {  
                 my $tempsection=$1;  
                 if($key eq $courseID.'_st') {  
                     $tempsection='';  
                 }                  }
                 my ($dummy,$roleend,$rolestart)=split(/\_/,$value);              }
                 if($roleend eq $end && $rolestart eq $start) {          }
                     $sec = $tempsection;      }
                     last;      if ($store_rows) {
           chop($store_command);
           $dbh->do($store_command);
           if ($dbh->err) {
               $returnstatus = 'error storing response data';
               &Apache::lonnet::logthis('insert error '.$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') {
           $returnstatus = 'error storing current data:'.$status;
       } elsif ($status ne 'okay') {
           $returnstatus .= ' error storing current data:'.$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;
   }
   
   ################################################
   ################################################
   
   =pod
   
   =item &update_student_data()
   
   Input: $sname, $sdom, $courseid
   
   Output: $returnstatus, \%student_data
   
   $returnstatus is a string describing any errors that occured.  '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.
   
   =cut
   
   ################################################
   ################################################
   sub update_student_data {
       my ($sname,$sdom,$courseid) = @_;
       #
       # Set up database names
       &setup_table_names($courseid);
       #
       my $student_id = &get_student_id($sname,$sdom);
       my @group_ids = &get_students_groupids($student_id);
       my $student = $sname.':'.$sdom;
       #
       my $returnstatus = 'okay';
       #
       # Download students data
       my $time_of_retrieval = time;
       my @tmp = &Apache::lonnet::currentdump($courseid,$sdom,$sname);
       if ((scalar(@tmp) > 0) && ($tmp[0] =~ /^error:/)) {
           &Apache::lonnet::logthis('error getting data for '.
                                    $sname.':'.$sdom.' in course '.$courseid.
                                    ':'.$tmp[0]);
           $returnstatus = 'error getting data';
           return ($returnstatus,undef);
       }
       if (scalar(@tmp) < 1) {
           return ('no data',undef);
       }
       my %student_data = @tmp;
       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;
   }
   
   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);
   }
   
   sub store_student_data {
       my ($sname,$sdom,$courseid,$student_data) = @_;
       #
       my $student_id = &get_student_id($sname,$sdom);
       my @group_ids = &get_students_groupids($student_id);
       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 $store_parameters_command  = 'INSERT IGNORE INTO '.$parameters_table.
           ' VALUES '."\n";
       my $num_parameters = 0;
       my $store_performance_command = 'INSERT IGNORE INTO '.$performance_table.
           ' VALUES '."\n";
       return ('error',undef) if (! defined($dbh));
       while (my ($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";
                   $num_parameters ++;
                   if ($sql_parameter !~ /''/) {
                       $store_parameters_command .= $sql_parameter;
                       #$rows_stored++;
                 }                  }
             }              }
         }          }
           # 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";
               $store_performance_command .= $sql_performance;
               $rows_stored++;
           }
       }
       if (! $rows_stored) { return ($returnstatus, undef); }
       $store_parameters_command =~ s|,\n$||;
       $store_performance_command =~ s|,\n$||;
       my $start = Time::HiRes::time;
       $dbh->do($store_performance_command);
       if ($dbh->err()) {
           &Apache::lonnet::logthis('performance bigass insert error:'.
                                    $dbh->errstr());
           &Apache::lonnet::logthis('command = '.$/.$store_performance_command);
           $returnstatus = 'error: unable to insert performance into database';
           return ($returnstatus,$student_data);
       }
       $dbh->do($store_parameters_command) if ($num_parameters>0);
       if ($dbh->err()) {
           &Apache::lonnet::logthis('parameters bigass insert error:'.
                                    $dbh->errstr());
           &Apache::lonnet::logthis('command = '.$/.$store_parameters_command);
           &Apache::lonnet::logthis('rows_stored = '.$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);
   }
   
         my $status='Expired';  ######################################
         if(((!$end) || time < $end) && ((!$start) || (time > $start))) {  ######################################
             $status='Active';  
   =pod
   
   =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
   
   =cut
   
   ######################################
   ######################################
   sub ensure_tables_are_set_up {
       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';
         }          }
         $cache->{$name.':Status'}=$status;  
         $cache->{$name.':section'}=$sec;  
     }      }
   }
   
   ################################################
   ################################################
   
   =pod
   
   =item &ensure_current_data()
   
   Input: $sname, $sdom, $courseid
   
   Output: $status, $data
   
   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.
   
     $cache->{'ClasslistTimestamp'}=time;  =cut
     $cache->{'NamesOfStudents'}=join(':::',@names);  
   
     return @names;  ################################################
   ################################################
   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 $modifiedtime = &Apache::lonnet::GetFileTimestamp
           ($sdom,$sname,$courseid.'.db',
            $Apache::lonnet::perlvar{'lonUsersDir'});
       #
       my $student_id = &get_student_id($sname,$sdom);
       my @group_ids = &get_students_groupids($student_id);
       my @Result = &Apache::lonmysql::get_rows($student_table,
                                                "student_id ='$student_id'");
       my $data = undef;
       if (@Result) {
           $updatetime = $Result[0]->[5];  # Ack!  This is dumb!
       }
       if ($modifiedtime > $updatetime) {
           ($status,$data) = &update_student_data($sname,$sdom,$courseid);
       }
       return ($status,$data);
 }  }
   
   ################################################
   ################################################
   
 =pod  =pod
   
 =item &ProcessStudentData()  =item &ensure_current_full_data($sname,$sdom,$courseid)
   
 Takes the course data downloaded for a student in   Input: $sname, $sdom, $courseid
 &DownloadCourseInformation() and breaks it up into key value pairs  
 to be stored in the cached data.  The keys are comprised of the   Output: $status
 $username:$domain:$keyFromCourseDatabase.  The student username:domain is  
 stored away signifying that the student's information has been downloaded and   This routine ensures the fulldata (the data from a lonnet::dump, not a
 can be reused from cached data.  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.
   
   =cut
   
   ################################################
   ################################################
   sub ensure_current_full_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 $modifiedtime = &Apache::lonnet::GetFileTimestamp
           ($sdom,$sname,$courseid.'.db',
            $Apache::lonnet::perlvar{'lonUsersDir'});
       #
       my $student_id = &get_student_id($sname,$sdom);
       my @group_ids = &get_students_groupids($student_id);
       my @Result = &Apache::lonmysql::get_rows($student_table,
                                                "student_id ='$student_id'");
       my $updatetime;
       if (@Result && ref($Result[0]) eq 'ARRAY') {
           $updatetime = $Result[0]->[6];
       }
       if (! defined($updatetime) || $modifiedtime > $updatetime) {
           $status = &update_full_student_data($sname,$sdom,$courseid);
       }
       return $status;
   }
   
   ################################################
   ################################################
   
   =pod
   
   =item &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.  
   
   =cut
   
   ################################################
   ################################################
   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;
   }
   
   ################################################
   ################################################
   
   =pod
   
   =item &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.
   
   =cut
   
   ################################################
   ################################################
   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 ();
           }
           my $returnhash = &get_student_data_from_performance_cache($sname,$sdom,
                                                         $symb,$courseid);
           return %$returnhash if (defined($returnhash));
       }
       return ();
   }
   
   ################################################
   ################################################
   
   =pod
   
   =item &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: $cache, $courseData, $name  =item $Sections Array ref containing section names for students.  
   'all' is allowed to be the first (and only) item in the array.
   
 $cache: A hash pointer to store data  =item $Groups Array ref containing group names for students.
   'all' is allowed to be the first (and only) item in the array.
   
 $courseData:  A hash pointer that points to the course data downloaded for a   =item $status String describing the status of students
 student.  
   
 $name:  username:domain  =item $symb is the symb for the problem.
   
 Output: None  =item $part is the part id you need statistics for
   
 *NOTE:  There is no output, but an error message is stored away in the cache   =item $courseid is the course id, of course!
 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 $starttime and $endtime are unix times which to use to limit
 &DownloadCourseInformation().  the statistical data.
   
   =back
   
   Outputs: See the code for up to date information.  A hash reference is
   returned.  The hash has the following keys defined:
   
   =over 4
   
   =item num_students The number of students attempting the problem
         
   =item tries The total number of tries for the students
         
   =item max_tries The maximum number of tries taken
         
   =item mean_tries The average number of tries
         
   =item num_solved The number of students able to solve the problem
         
   =item num_override The number of students whose answer is 'correct_by_override'
         
   =item deg_of_diff The degree of difficulty of the problem
         
   =item std_tries The standard deviation of the number of tries
         
   =item skew_tries The skew of the number of tries
   
   =item per_wrong The number of students attempting the problem who were not
   able to answer it correctly.
   
 =back  =back
   
 =cut  =cut
   
 sub ProcessStudentData {  ################################################
     my ($cache,$courseData,$name)=@_;  ################################################
   sub get_problem_statistics {
       my ($Sections,$Groups,$status,$symb,$part,$courseid,$starttime,$endtime) = @_;
       return if (! defined($symb) || ! defined($part));
       $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 = $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='.$part_id;
       #
       # Limit the students included to those specified
       if (defined($Sections) && lc($Sections->[0]) ne 'all') {
           $request .= ' AND ('.
               join(' OR ', map { "b.section='".$_."'" } @$Sections
                    ).')';
       }
       if (defined($status) && lc($status) ne 'any') {
           $request .= " AND b.status='".$status."'";
       }
       #
       # 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;
       }
       # 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';
       if (defined($time_requirements)) {
           $request .= ' AND '.$time_requirements;
       }
       my ($max,$min) = &execute_SQL_request($dbh,$request);
       #
       $request = 'SELECT SUM(awarded) FROM '.$stats_table;
       if (defined($time_requirements)) {
           $request .= ' AND '.$time_requirements;
       }
       my ($Solved) = &execute_SQL_request($dbh,$request);
       #
       $request = 'SELECT SUM(awarded) FROM '.$stats_table.
           " WHERE solved='correct_by_override'";
       if (defined($time_requirements)) {
           $request .= ' AND '.$time_requirements;
       }
       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 };
   }
   
   ##
   ## 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 ();
   }
   
     if($courseData->{'UpToDate'} eq 'true') {  ######################################################
         $cache->{$name.':lastDownloadTime'}=$courseData->{'lastDownloadTime'};  ######################################################
   
   =pod
   
   =item &populate_weight_table
   
   =cut
   
   ######################################################
   ######################################################
   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;          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().
                                    " occured executing \n".
                                    $request);
       }
       return;
   }
   
   ##########################################################
   ##########################################################
   
   =pod
   
     my @courseKeys = keys(%$courseData);  =item &limit_by_start_end_times
   
     foreach (@courseKeys) {  Build SQL WHERE condition which limits the data collected by the start
         if(/^(con_lost|error|no_such_host)/i) {  and end times provided
             $cache->{$name.':error'}='Could not download course data.';  
             return;  Inputs: $starttime, $endtime, $table
   
   Returns: $time_limits
   
   =cut
   
   ##########################################################
   ##########################################################
   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;
   }
   
     $cache->{$name.':lastDownloadTime'}=$courseData->{'lastDownloadTime'};  ##########################################################
     foreach (@courseKeys) {  ##########################################################
         $cache->{$name.':'.$_}=$courseData->{$_};  
   =pod
   
   =item &limit_by_section_and_status
   
   Build SQL WHERE condition which limits the data collected by section and
   student status.
   
   Inputs: $Sections (array ref)
       $enrollment (string: 'any', 'expired', 'active')
       $tablename The name of the table that holds the student data
   
   Returns: $student_requirements,$enrollment_requirements
   
   =cut
   
   ##########################################################
   ##########################################################
   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') {
           $enrollment_requirements = $tablename.".status='".$enrollment."'";
       }
       return ($student_requirements,$enrollment_requirements);
   }
   
     return;  ######################################################
   ######################################################
                                                                                  
   =pod
                                                                                  
   =item &limit_by_group
                                                                                  
   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
   =cut
   
   sub limit_by_group {
       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);
 }  }
   
 sub LoadDiscussion {  =pod
     my ( $courseID)=@_;  
     my %Discuss=();  =item rank_students_by_scores_on_resources
     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;  Inputs: 
       $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)
   
   Returns; An array of arrays.  The sub arrays contain a student name and
   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. 
   
   =cut
   
   ######################################################
   ######################################################
   sub RNK_student { return 0; };
   sub RNK_score   { return 1; };
   
   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 .= " $award_clause GROUP BY a.student_id ORDER BY score";
       #&Apache::lonnet::logthis('request = '.$/.$request);
       my $sth = $dbh->prepare($request) or die "Can't prepare $request";
       $sth->execute();
       my $rows = $sth->fetchall_arrayref();
       return ($rows);
 }  }
   
 # ----- END PROCESSING FUNCTIONS ---------------------------------------  ########################################################
   ########################################################
   
 =pod  =pod
   
 =head1 HELPER FUNCTIONS  =item &get_sum_of_scores
   
 These are just a couple of functions do various odd and end   Inputs: $resource (hash ref, needs {'symb'} key),
 jobs.  $part, (the part id),
   $students (array ref, contents of array are scalars holding 'sname:sdom'),
   $courseid
   
   Returns: the sum of the score on the problem part over the students and the
      maximum possible value for the sum (taken from the weight table).
   
 =cut  =cut
   
 # ----- HELPER FUNCTIONS -----------------------------------------------  ########################################################
   ########################################################
   sub get_sum_of_scores {
       my ($symb,$part,$students,$courseid,$starttime,$endtime) = @_;
       if (! defined($courseid)) {
           $courseid = $env{'request.course.id'};
       }
       if (defined($students) && 
           ((@$students == 0) ||
            (@$students == 1 && (! defined($students->[0]) || 
                                 $students->[0] eq ''))
            )
           ){
           undef($students);
       }
       #
       &setup_table_names($courseid);
       my $dbh = &Apache::lonmysql::get_dbh();
       my $time_limits = &limit_by_start_end_time($starttime,$endtime,'a');
       my $request = 'SELECT SUM(a.awarded*w.weight),SUM(w.weight) FROM '.
           $performance_table.' AS a '.
           'NATURAL LEFT JOIN '.$weight_table.' AS w ';
       $request .= 'WHERE a.symb_id='.&get_symb_id($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]);
   }
   
   ########################################################
   ########################################################
   
 =pod  =pod
   
 =item &ProcessFullName()  =item &score_stats
   
   Inputs: $Sections, $enrollment, $symbs, $starttime,
           $endtime, $courseid
   
 Takes lastname, generation, firstname, and middlename (or some partial  $Sections, $enrollment, $starttime, $endtime, and $courseid are the same as 
 set of this data) and returns the full name version as a string.  Format  elsewhere in this module.  
 is Lastname generation, firstname middlename or a subset of this.  $symbs is an array ref of symbs
   
   Returns: minimum, maximum, mean, s.d., number of students, and maximum
     possible of student scores on the given resources
   
 =cut  =cut
   
 sub ProcessFullName {  ########################################################
     my ($lastname, $generation, $firstname, $middlename)=@_;  ########################################################
     my $Str = '';  sub score_stats {
       my ($Sections,$Groups,$enrollment,$symbs,$starttime,$endtime,$courseid)=@_;
       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 $time_limits = &limit_by_start_end_time($starttime,$endtime,'a');
       my @Symbids = map { &get_symb_id($_); } @{$symbs};
       #
       my $stats_table = $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);
   }
   
     if($lastname ne '') {  
  $Str .= $lastname.' ';  ########################################################
  if($generation ne '') {  ########################################################
     $Str .= $generation;  
  } else {  =pod
     chop($Str);  
  }  =item &count_stats
  $Str .= ', ';  
  if($firstname ne '') {  Inputs: $Sections, $Groups, $enrollment, $symbs, $starttime,
     $Str .= $firstname.' ';          $endtime, $courseid
  }  
  if($middlename ne '') {  $Sections, $Groups $enrollment, $starttime, $endtime, and $courseid are the 
     $Str .= $middlename;  same as elsewhere in this module.  
  } else {  $symbs is an array ref of symbs
     chop($Str);  
     if($firstname eq '') {  Returns: minimum, maximum, mean, s.d., and number of students
  chop($Str);    of the number of items correct on the given resources
     }  
  }  =cut
     } else {  
  if($firstname ne '') {  ########################################################
     $Str .= $firstname.' ';  ########################################################
  }  sub count_stats {
  if($middlename ne '') {      my ($Sections,$Groups,$enrollment,$symbs,$starttime,$endtime,$courseid)=@_;
     $Str .= $middlename.' ';      if (! defined($courseid)) {
  }          $courseid = $env{'request.course.id'};
  if($generation ne '') {      }
     $Str .= $generation;      #
  } else {      &setup_table_names($courseid);
     chop($Str);      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 $time_limits = &limit_by_start_end_time($starttime,$endtime,'a');
       my @Symbids = map { &get_symb_id($_); } @{$symbs};
       #
       my $stats_table = $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) AS count FROM '.
           $performance_table.' AS a '.
           'LEFT JOIN '.$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();
       $request = 
           'SELECT AVG(count),STD(count),MAX(count),MIN(count),COUNT(count) '.
           'FROM '.$stats_table;
       my ($ave,$std,$max,$min,$count) = &execute_SQL_request($dbh,$request);
   #    &Apache::lonnet::logthis('request = '.$/.$request);
       return($min,$max,$ave,$std,$count);
   }
   
   ######################################################
   ######################################################
   
   =pod
   
     return $Str;  =item get_student_data
   
   =cut
   
   ######################################################
   ######################################################
   sub get_student_data {
       my ($students,$courseid) = @_;
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       &setup_table_names($courseid);
       my $dbh = &Apache::lonmysql::get_dbh();
       return undef if (! defined($dbh));
       my $request = 'SELECT '.
           'student_id, student '.
           'FROM '.$student_table;
       if (defined($students)) {
           $request .= ' WHERE ('.
               join(' OR ', map {'student_id='.
                                     &get_student_id($_->{'username'},
                                                     $_->{'domain'})
                                 } @$students
                    ).')';
       }
       $request.= ' ORDER BY student_id';
       my $sth = $dbh->prepare($request);
       $sth->execute();
       if ($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;
       }
 }  }
   
   sub RD_student_id      { return 0; }
   sub RD_awarddetail     { return 1; }
   sub RD_response_eval   { return 2; }
   sub RD_response_eval_2 { return 3; }
   sub RD_submission      { return 4; }
   sub RD_timestamp       { return 5; }
   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]->[3] =~ s/(\'$|^\')//g;
           }
           return $dataset;
       }
   }
   
   
   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'},
                                        $student->{'domain'});
       my @group_ids = &get_students_groupids($student_id);
       #
       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]->[2] =~ s/(\'$|^\')//g;
           }
           return $dataset;
       }
       return undef; # error occurred
   }
   
   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;
       }
   
   }
   
   ################################################
   ################################################
   
 =pod  =pod
   
 =item &TestCacheData()  =item &get_student_scores($Sections,$Groups,$Symbs,$enrollment,$courseid)
   
 Determine if the cache database can be accessed with a tie.  It waits up to  =cut
 ten seconds before returning failure.  This function exists to help with  
 the problems with stopping the data download.  When an abort occurs and the  
 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).  
   
 =over 4  ################################################
   ################################################
   sub get_student_scores {
       my ($sections,$groups,$Symbs,$enrollment,$courseid,$starttime,$endtime) = @_;
       $courseid = $env{'request.course.id'} if (! defined($courseid));
       &setup_table_names($courseid);
       my $dbh = &Apache::lonmysql::get_dbh();
       return (undef) if (! defined($dbh));
       my $tmptable = $courseid.'_temp_'.time;
       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;
   }
   
 Input: $ChartDB  ################################################
   ################################################
   
 $ChartDB: The name of the cache database to be opened  =pod
   
   =item &setup_table_names()
   
   input: course id
   
   output: none
   
 Output: -1, 0, 1  Cleans up the package variables for local caching.
   
 -1: Couldn't tie database  =cut
  0: Use cached data  
  1: New cache database created, use that.  ################################################
   ################################################
   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 = $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;
   }
   
   ################################################
   ################################################
   
   =pod
   
 =back  =back
   
   =item End of Local Data Caching Subroutines
   
 =cut  =cut
   
 sub TestCacheData {  ################################################
     my ($ChartDB,$isRecalculate,$totalDelay)=@_;  ################################################
     my $isCached=-1;  
     my %testData;  
     my $tieTries=0;  
   
     if(!defined($totalDelay)) {  } # End scope of table identifiers
         $totalDelay = 10;  
     }  
   
     if ((-e "$ChartDB") && (!$isRecalculate)) {  ################################################
  $isCached = 1;  ################################################
     } else {  
  $isCached = 0;  =pod
     }  
   =head3 Classlist Subroutines
   
   =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]
   
   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.
   
   =cut
   
     while($tieTries < $totalDelay) {  ################################################
         my $result=0;  ################################################
         if($isCached) {  
             $result=tie(%testData,'GDBM_File',$ChartDB,&GDBM_READER,0640);  sub CL_SDOM     { return 0; }
         } else {  sub CL_SNAME    { return 1; }
             $result=tie(%testData,'GDBM_File',$ChartDB,&GDBM_NEWDB,0640);  sub CL_END      { return 2; }
   sub CL_START    { return 3; }
   sub CL_ID       { return 4; }
   sub CL_SECTION  { return 5; }
   sub CL_FULLNAME { return 6; }
   sub CL_STATUS   { return 7; }
   sub CL_TYPE     { return 8; }
   sub CL_LOCKEDTYPE   { return 9; }
   
   sub get_classlist {
       my ($cdom,$cnum) = @_;
       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 $now = time;
       #
       my %classlist=&Apache::lonnet::dump('classlist',$cdom,$cnum);
       while (my ($student,$info) = each(%classlist)) {
           if ($student =~ /^(con_lost|error|no_such_host)/i) {
               &Apache::lonnet::logthis('get_classlist error for '.$cid.':'.$student);
               return undef;
         }          }
         if($result) {          my ($sname,$sdom) = split(/:/,$student);
             last;          my @Values = split(/:/,$info);
           my ($end,$start,$id,$section,$fullname,$type,$lockedtype);
           if (@Values > 2) {
               ($end,$start,$id,$section,$fullname,$type,$lockedtype) = @Values;
           } else { # We have to get the data ourselves
               ($end,$start) = @Values;
               $section = &Apache::lonnet::getsection($sdom,$sname,$cid);
               my %info=&Apache::lonnet::get('environment',
                                             ['firstname','middlename',
                                              'lastname','generation','id'],
                                             $sdom, $sname);
               my ($tmp) = keys(%info);
               if ($tmp =~/^(con_lost|error|no_such_host)/i) {
                   $fullname = 'not available';
                   $id = 'not available';
                   &Apache::lonnet::logthis('unable to retrieve environment '.
                                            'for '.$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 $status='Expired';
           if(((!$end) || $now < $end) && ((!$start) || ($now > $start))) {
               $status='Active';
         }          }
         $tieTries++;          $classlist{$student} = 
         sleep 1;              [$sdom,$sname,$end,$start,$id,$section,$fullname,$status,$type,$lockedtype];
     }      }
     if($tieTries >= $totalDelay) {      if (wantarray()) {
         return -1;          return (\%classlist,['domain','username','end','start','id',
                                'section','fullname','status','type','lockedtype']);
       } else {
           return \%classlist;
     }      }
   
     untie(%testData);  
   
     return $isCached;  
 }  }
   
 sub GetFileTimestamp {  sub get_group_memberships {
     my ($studentDomain,$studentName,$filename,$root)=@_;      my ($classlist,$keylist,$cdom,$cnum) = @_;
     $studentDomain=~s/\W//g;      my $cid = $cdom.'_'.$cnum;
     $studentName=~s/\W//g;      if (!defined($cdom) || !defined($cnum)) {
     my $subdir=$studentName.'__';          $cid =  $env{'request.course.id'};
     $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;          $cdom = $env{'course.'.$cid.'.domain'};
     my $proname="$studentDomain/$subdir/$studentName";          $cnum = $env{'course.'.$cid.'.num'};
     $proname .= '/'.$filename;      }
     my @dir = &Apache::lonnet::dirlist($proname, $studentDomain, $studentName,      my (%classgroups,%studentgroups);
                                        $root);      my $now = time;
     my $fileStat = $dir[0];      my $access_end = $env{'course.'.$cid.'.default_enrollment_end_date'};
     my @stats = split('&', $fileStat);      my %curr_groups =&Apache::loncommon::coursegroups($cdom,$cnum);
     if(@stats) {      if (%curr_groups) {
         return $stats[9];          my $grpindex = scalar(@{$keylist});
           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'}})));
               }
           }
       }
       return (\%classgroups,\%studentgroups);
   }
                                                                                      
   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 {      } else {
         return -1;          if (ref($$classgroups{$student}{'aftercourse'}) eq 'HASH') {
               push(@studentsgroups,keys(%{$$classgroups{$student}{'aftercourse'}}));
           }
     }      }
       return @studentsgroups;
 }  }
   
   
 # ----- END HELPER FUNCTIONS --------------------------------------------  # ----- END HELPER FUNCTIONS --------------------------------------------
   
 1;  1;
 __END__  __END__
   

Removed from v.1.5  
changed lines
  Added in v.1.170


FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>