Annotation of loncom/interface/lonmysql.pm, revision 1.4
1.1 matthew 1: # The LearningOnline Network with CAPA
2: # MySQL utility functions
3: #
1.4 ! matthew 4: # $Id: lonmysql.pm,v 1.3 2002/07/30 18:26:40 matthew Exp $
1.1 matthew 5: #
6: # Copyright Michigan State University Board of Trustees
7: #
8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
9: #
10: # LON-CAPA is free software; you can redistribute it and/or modify
11: # it under the terms of the GNU General Public License as published by
12: # the Free Software Foundation; either version 2 of the License, or
13: # (at your option) any later version.
14: #
15: # LON-CAPA is distributed in the hope that it will be useful,
16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18: # GNU General Public License for more details.
19: #
20: # You should have received a copy of the GNU General Public License
21: # along with LON-CAPA; if not, write to the Free Software
22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23: #
24: # /home/httpd/html/adm/gpl.txt
25: #
26: # http://www.lon-capa.org/
27: #
28: ######################################################################
29:
30: package Apache::lonmysql;
31:
32: use strict;
33: use DBI;
34: use Apache::lonnet();
35:
36: ######################################################################
37: ######################################################################
38:
39: =pod
40:
41: =head1 Name
42:
43: lonmysql - LONCAPA MySQL utility functions
44:
45: =head1 Synopsis
46:
47: lonmysql contains utility functions to make accessing the mysql loncapa
48: database easier.
49:
50: =head1 Description
51:
52: lonmysql does its best to encapsulate all the database/table functions
53: and provide a common interface. The goal, however, is not to provide
54: a complete reimplementation of the DBI interface. Instead we try to
55: make using mysql as painless as possible.
56:
57: Each table has a numeric ID that is a parameter to most lonmysql functions.
58: The table id is returned by &create_table.
59: If you lose the table id, it is lost forever.
60: The table names in MySQL correspond to
61: $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.$table_id. If the table id
62: is non-numeric, it is assumed to be the full name of a table. If you pass
63: the table id in a form, you MUST ensure that what you send to lonmysql is
64: numeric, otherwise you are opening up all the tables in the MySQL database.
65:
66: =over 4
67:
68: =item Creating a table
69:
70: To create a table, you need a description of its structure. See the entry
71: for &create_table for a description of what is needed.
72:
73: $table_id = &create_table({
74: columns => {
75: id => {
76: type => 'INT',
77: restrictions => 'NOT NULL',
78: primary_key => 'yes',
79: auto_inc => 'yes'
80: }
81: verbage => { type => 'TEXT' },
82: },
1.3 matthew 83: column_order => [qw/id verbage idx_verbage/],
84: fulltext => [qw/verbage/],
85: });
1.1 matthew 86:
87: The above command will create a table with two columns, 'id' and 'verbage'.
88:
89: 'id' will be an integer which is autoincremented and non-null.
90:
91: 'verbage' will be of type 'TEXT', which (conceivably) allows any length
92: text string to be stored. Depending on your intentions for this database,
93: setting restrictions => 'NOT NULL' may help you avoid storing empty data.
94:
1.3 matthew 95: the fulltext element sets up the 'verbage' column for 'FULLTEXT' searching.
1.1 matthew 96:
97:
98:
99: =item Storing rows
100:
101: Storing a row in a table requires calling &store_row($table_id,$data)
102:
103: $data is either a hash reference or an array reference. If it is an array
104: reference, the data is passed as is (after being escaped) to the
105: "INSERT INTO <table> VALUES( ... )" SQL command. If $data is a hash reference,
106: the data will be placed into an array in the proper column order for the table
107: and then passed to the database.
108:
109: An example of inserting into the table created above is:
110:
111: &store_row($table_id,[undef,'I am not a crackpot!']);
112:
113: or equivalently,
114:
115: &store_row($table_id,{ verbage => 'I am not a crackpot!'});
116:
117: Since the above table was created with the first column ('id') as
118: autoincrement, providing a value is unnecessary even though the column was
119: marked as 'NOT NULL'.
120:
121:
122:
123: =item Retrieving rows
124:
125: Retrieving rows requires calling get_rows:
126:
127: @row = &Apache::lonmysql::get_rows($table_id,$condition)
128:
129: This results in the query "SELECT * FROM <table> HAVING $condition".
130:
131: @row = &Apache::lonmysql::get_rows($table_id,'id>20');
132:
133: returns all rows with column 'id' greater than 20.
134:
135: =back
136:
137: =cut
138:
139: ######################################################################
140: ######################################################################
141: =pod
142:
143: =head1 Package Variables
144:
145: =over 4
146:
147: =cut
148:
149: ##################################################
150: ##################################################
151:
152: =pod
153:
154: =item %Tables
155:
156: Holds information regarding the currently open connections. Each key
157: in the %Tables hash will be a unique table key. The value associated
158: with a key is a hash reference. Most values are initialized when the
159: table is created.
160:
161: The following entries are allowed in the hash reference:
162:
163: =over 4
164:
1.3 matthew 165: =item Name
166:
167: Table name.
168:
169: =item Type
170:
171: The type of table, typically MyISAM.
172:
173: =item Row_format
174:
175: Describes how rows should be stored in the table. DYNAMIC or STATIC.
176:
177: =item Create_time
178:
179: The date of the tables creation.
180:
181: =item Update_time
182:
183: The date of the last modification of the table.
184:
185: =item Check_time
186:
187: Usually NULL.
188:
189: =item Avg_row_length
190:
191: The average length of the rows.
192:
193: =item Data_length
194:
195: The length of the data stored in the table (bytes)
196:
197: =item Max_data_length
198:
199: The maximum possible size of the table (bytes).
1.1 matthew 200:
1.3 matthew 201: =item Index_length
1.1 matthew 202:
1.3 matthew 203: The length of the index for the table (bytes)
1.1 matthew 204:
1.3 matthew 205: =item Data_free
1.1 matthew 206:
1.3 matthew 207: I have no idea what this is.
1.1 matthew 208:
1.3 matthew 209: =item Comment
1.1 matthew 210:
1.3 matthew 211: The comment associated with the table.
212:
213: =item Rows
214:
215: The number of rows in the table.
216:
217: =item Auto_increment
218:
219: The value of the next auto_increment field.
220:
221: =item Create_options
222:
223: I have no idea.
224:
225: =item Col_order
226:
227: an array reference which holds the order of columns in the table.
228:
229: =item row_insert_sth
1.1 matthew 230:
231: The statement handler for row inserts.
232:
233: =back
234:
1.3 matthew 235: Col_order and row_insert_sth are kept internally by lonmysql and are not
236: part of the usual MySQL table information.
237:
1.1 matthew 238: =cut
239:
240: ##################################################
241: ##################################################
242: my %Tables;
243:
244: ##################################################
245: ##################################################
246: =pod
247:
248: =item $errorstring
249:
250: Holds the last error.
251:
252: =cut
253: ##################################################
254: ##################################################
255: my $errorstring;
256:
257: ##################################################
258: ##################################################
259: =pod
260:
261: =item $debugstring
262:
263: Describes current events within the package.
264:
265: =cut
266: ##################################################
267: ##################################################
268: my $debugstring;
269:
270: ##################################################
271: ##################################################
272:
273: =pod
274:
275: =item $dbh
276:
277: The database handler; The actual connection to MySQL via the perl DBI.
278:
279: =cut
280:
281: ##################################################
282: ##################################################
283: my $dbh;
284:
285: ##################################################
286: ##################################################
287:
288: # End of global variable declarations
289:
290: =pod
291:
292: =back
293:
294: =cut
295:
296: ######################################################################
297: ######################################################################
298:
299: =pod
300:
301: =head1 Internals
302:
303: =over 4
304:
305: =cut
306:
307: ######################################################################
308: ######################################################################
309:
310: =pod
311:
312: =item &connect_to_db()
313:
314: Inputs: none.
315:
316: Returns: undef on error, 1 on success.
317:
318: Checks to make sure the database has been connected to. If not, the
319: connection is established.
320:
321: =cut
322:
323: ###############################
324: sub connect_to_db {
325: return 1 if ($dbh);
326: if (! ($dbh = DBI->connect("DBI:mysql:loncapa","www",
327: $Apache::lonnet::perlvar{'lonSqlAccess'},
328: { RaiseError=>0,PrintError=>0}))) {
329: $debugstring = "Unable to connect to loncapa database.";
330: if ($dbh->err) {
331: $errorstring = "Connection error: ".$dbh->errstr;
332: }
333: return undef;
334: }
335: $debugstring = "Successfully connected to loncapa database.";
336: return 1;
337: }
338:
339: ###############################
340:
341: =pod
342:
343: =item &disconnect_from_db()
344:
345: Inputs: none.
346:
347: Returns: Always returns 1.
348:
349: Severs the connection to the mysql database.
350:
351: =cut
352:
353: ###############################
354: sub disconnect_from_db {
355: foreach (keys(%Tables)) {
356: # Supposedly, having statement handlers running around after the
357: # database connection has been lost will cause trouble. So we
358: # kill them off just to be sure.
359: if (exists($Tables{$_}->{'row_insert_sth'})) {
360: delete($Tables{$_}->{'row_insert_sth'});
361: }
362: }
363: $dbh->disconnect if ($dbh);
364: $debugstring = "Disconnected from database.";
365: $dbh = undef;
366: return 1;
367: }
368:
369: ###############################
370:
371: =pod
372:
1.2 matthew 373: =item &number_of_rows()
1.1 matthew 374:
1.2 matthew 375: Input: table identifier
376:
1.3 matthew 377: Returns: the number of rows in the given table, undef on error.
1.1 matthew 378:
379: =cut
380:
381: ###############################
1.2 matthew 382: sub number_of_rows {
383: my ($table_id) = @_;
1.3 matthew 384: return undef if (! defined(&connect_to_db()));
385: return undef if (! defined(&update_table_info($table_id)));
386: return $Tables{&translate_id($table_id)}->{'Rows'};
1.1 matthew 387: }
388:
389: ###############################
390:
391: =pod
392:
393: =item &get_error()
394:
395: Inputs: none.
396:
397: Returns: The last error reported.
398:
399: =cut
400:
401: ###############################
402: sub get_error {
403: return $errorstring;
404: }
405:
406: ###############################
407:
408: =pod
409:
410: =item &get_debug()
411:
412: Inputs: none.
413:
414: Returns: A string describing the internal state of the lonmysql package.
415:
416: =cut
417:
418: ###############################
419: sub get_debug {
420: return $debugstring;
421: }
422:
423: ###############################
424:
425: =pod
426:
1.3 matthew 427: =item &update_table_info($table_id)
1.1 matthew 428:
429: Inputs: table id
430:
1.3 matthew 431: Returns: undef on error, 1 on success.
1.1 matthew 432:
1.3 matthew 433: &update_table_info updates the %Tables hash with current information about
434: the given table.
435:
436: The default MySQL table status fields are:
1.1 matthew 437:
438: Name Type Row_format
439: Max_data_length Index_length Data_free
440: Create_time Update_time Check_time
441: Avg_row_length Data_length Comment
442: Rows Auto_increment Create_options
443:
1.3 matthew 444: Additionally, "Col_order" is updated as well.
445:
1.1 matthew 446: =cut
447:
448: ###############################
1.3 matthew 449: sub update_table_info {
1.1 matthew 450: my ($table_id) = @_;
1.3 matthew 451: return undef if (! defined(&connect_to_db()));
452: my $table_status = &check_table($table_id);
453: return undef if (! defined($table_status));
454: if (! $table_status) {
455: $errorstring = "table $table_id does not exist.";
456: return undef;
457: }
1.1 matthew 458: my $tablename = &translate_id($table_id);
1.3 matthew 459: #
460: # Get MySQLs table status information.
461: #
1.1 matthew 462: my @tabledesc = qw/
463: Name Type Row_format Rows Avg_row_length Data_length
464: Max_data_length Index_length Data_free Auto_increment
465: Create_time Update_time Check_time Create_options Comment /;
466: my $db_command = "SHOW TABLE STATUS FROM loncapa LIKE '$tablename'";
467: my $sth = $dbh->prepare($db_command);
468: $sth->execute();
469: if ($sth->err) {
470: $errorstring = "$dbh ATTEMPTED:\n".$db_command."\nRESULTING ERROR:\n".
471: $sth->errstr;
1.3 matthew 472: &disconnect_from_db();
1.1 matthew 473: return undef;
474: }
475: #
476: my @info=$sth->fetchrow_array;
477: for (my $i=0;$i<= $#info ; $i++) {
1.3 matthew 478: $Tables{$tablename}->{$tabledesc[$i]}= $info[$i];
479: }
480: #
481: # Determine the column order
482: #
483: $db_command = "DESCRIBE $tablename";
484: my $sth = $dbh->prepare($db_command);
485: $sth->execute();
486: if ($sth->err) {
487: $errorstring = "$dbh ATTEMPTED:\n".$db_command."\nRESULTING ERROR:\n".
488: $sth->errstr;
489: &disconnect_from_db();
490: return undef;
491: }
492: my $aref=$sth->fetchall_arrayref;
493: $Tables{$tablename}->{'Col_order'}=[]; # Clear values.
494: # The values we want are the 'Field' entries, the first column.
495: for (my $i=0;$i< @$aref ; $i++) {
496: push @{$Tables{$tablename}->{'Col_order'}},$aref->[$i]->[0];
1.1 matthew 497: }
498: #
499: $debugstring = "Retrieved table info for $tablename";
1.3 matthew 500: return 1;
1.1 matthew 501: }
502:
503: ###############################
504:
505: =pod
506:
507: =item &create_table
508:
509: Inputs:
510: table description
511:
512: Input formats:
513:
514: table description = {
515: permanent => 'yes' or 'no',
516: columns => {
517: colA => {
518: type => mysql type,
519: restrictions => 'NOT NULL' or empty,
520: primary_key => 'yes' or empty,
521: auto_inc => 'yes' or empty,
522: }
523: colB => { .. }
524: colZ => { .. }
525: },
526: column_order => [ colA, colB, ..., colZ],
527: }
528:
529: Returns:
530: undef on error, table id on success.
531:
532: =cut
533:
534: ###############################
535: sub create_table {
1.3 matthew 536: return undef if (!defined(&connect_to_db($dbh)));
1.1 matthew 537: my ($table_des)=@_;
538: #
539: # Build request to create table
540: ##################################
541: my @Columns;
542: my $col_des;
1.3 matthew 543: my $table_id = &get_new_table_id();
544: my $tablename = &translate_id($table_id);
1.1 matthew 545: my $request = "CREATE TABLE IF NOT EXISTS ".$tablename." ";
546: foreach my $column (@{$table_des->{'column_order'}}) {
547: $col_des = '';
548: my $coldata = $table_des->{'columns'}->{$column};
1.3 matthew 549: if (lc($coldata->{'type'}) =~ /(enum|set)/) { # 'enum' or 'set'
1.1 matthew 550: $col_des.=$column." ".$coldata->{'type'}."('".
551: join("', '",@{$coldata->{'values'}})."')";
552: } else {
553: $col_des.=$column." ".$coldata->{'type'};
554: if (exists($coldata->{'size'})) {
555: $col_des.="(".$coldata->{'size'}.")";
556: }
557: }
558: # Modifiers
559: if (exists($coldata->{'restrictions'})){
560: $col_des.=" ".$coldata->{'restrictions'};
561: }
562: if (exists($coldata->{'default'})) {
563: $col_des.=" DEFAULT '".$coldata->{'default'}."'";
564: }
1.3 matthew 565: $col_des.=' AUTO_INCREMENT' if (exists($coldata->{'auto_inc'}) &&
566: ($coldata->{'auto_inc'} eq 'yes'));
567: $col_des.=' PRIMARY KEY' if (exists($coldata->{'primary_key'}) &&
568: ($coldata->{'primary_key'} eq 'yes'));
1.1 matthew 569: } continue {
570: # skip blank items.
571: push (@Columns,$col_des) if ($col_des ne '');
572: }
1.4 ! matthew 573: if (exists($table_des->{'fulltext'}) && (@{$table_des->{'fulltext'}})) {
1.3 matthew 574: push (@Columns,'FULLTEXT ('.join(',',@{$table_des->{'fulltext'}}).')');
575: }
1.1 matthew 576: $request .= "(".join(", ",@Columns).") ";
577: unless($table_des->{'permanent'} eq 'yes') {
578: $request.="COMMENT = 'temporary' ";
579: }
580: $request .= "TYPE=MYISAM";
581: #
582: # Execute the request to create the table
583: #############################################
584: my $count = $dbh->do($request);
585: if (! defined($count)) {
1.3 matthew 586: $errorstring = "$dbh ATTEMPTED:\n".$request."\nRESULTING ERROR:\n";
1.1 matthew 587: return undef;
588: }
589: #
590: # Set up the internal bookkeeping
591: #############################################
592: delete($Tables{$tablename}) if (exists($Tables{$tablename}));
1.3 matthew 593: return undef if (! defined(&update_table_info($table_id)));
594: $debugstring = "Created table $tablename at time ".time.
1.1 matthew 595: " with request\n$request";
1.3 matthew 596: return $table_id;
1.1 matthew 597: }
598:
599: ###############################
600:
601: =pod
602:
603: =item &get_new_table_id
604:
605: Used internally to prevent table name collisions.
606:
607: =cut
608:
609: ###############################
610: sub get_new_table_id {
611: my $newid = 0;
612: my $name_regex = '^'.$ENV{'user.name'}.'_'.$ENV{'user.domain'}."_(\d+)\$";
613: my @tables = &tables_in_db();
614: foreach (@tables) {
615: if (/^$ENV{'user.name'}_$ENV{'user.domain'}_(\d+)$/) {
616: $newid = $1 if ($1 > $newid);
617: }
618: }
619: return ++$newid;
620: }
621:
622: ###############################
623:
624: =pod
625:
626: =item &get_rows
627:
628: Inputs: $table_id,$condition
629:
630: Returns: undef on error, an array ref to (array of) results on success.
631:
1.2 matthew 632: Internally, this function does a 'SELECT * FROM table WHERE $condition'.
1.1 matthew 633: $condition = 'id>0' will result in all rows where column 'id' has a value
634: greater than 0 being returned.
635:
636: =cut
637:
638: ###############################
639: sub get_rows {
640: my ($table_id,$condition) = @_;
1.3 matthew 641: return undef if (! defined(&connect_to_db()));
642: my $table_status = &check_table($table_id);
643: return undef if (! defined($table_status));
644: if (! $table_status) {
645: $errorstring = "table $table_id does not exist.";
646: return undef;
647: }
1.1 matthew 648: my $tablename = &translate_id($table_id);
1.2 matthew 649: my $request = 'SELECT * FROM '.$tablename.' WHERE '.$condition;
1.1 matthew 650: my $sth=$dbh->prepare($request);
651: $sth->execute();
652: if ($sth->err) {
653: $errorstring = "$dbh ATTEMPTED:\n".$request."\nRESULTING ERROR:\n".
654: $sth->errstr;
655: $debugstring = "Failed to get rows matching $condition";
656: return undef;
657: }
658: $debugstring = "Got rows matching $condition";
659: my @Results = @{$sth->fetchall_arrayref};
660: foreach my $row (@Results) {
661: for(my $i=0;$i<@$row;$i++) {
662: $row->[$i]=&Apache::lonnet::unescape($row->[$i]);
663: }
664: }
665: return @Results;
666: }
667:
668: ###############################
669:
670: =pod
671:
672: =item &store_row
673:
674: Inputs: table id, row data
675:
676: returns undef on error, 1 on success.
677:
678: =cut
679:
680: ###############################
681: sub store_row {
682: my ($table_id,$rowdata) = @_;
1.3 matthew 683: #
684: return undef if (! defined(&connect_to_db()));
685: my $table_status = &check_table($table_id);
686: return undef if (! defined($table_status));
687: if (! $table_status) {
688: $errorstring = "table $table_id does not exist.";
689: return undef;
690: }
691: #
1.1 matthew 692: my $tablename = &translate_id($table_id);
1.3 matthew 693: #
1.1 matthew 694: my $sth;
1.3 matthew 695: if (exists($Tables{$tablename}->{'row_insert_sth'})) {
696: $sth = $Tables{$tablename}->{'row_insert_sth'};
1.1 matthew 697: } else {
1.3 matthew 698: # Build the insert statement handler
699: return undef if (! defined(&update_table_info($table_id)));
1.1 matthew 700: my $insert_request = 'INSERT INTO '.$tablename.' VALUES(';
1.3 matthew 701: foreach (@{$Tables{$tablename}->{'Col_order'}}) {
1.1 matthew 702: $insert_request.="?,";
703: }
704: chop $insert_request;
705: $insert_request.=")";
706: $sth=$dbh->prepare($insert_request);
1.3 matthew 707: $Tables{$tablename}->{'row_insert_sth'}=$sth;
1.1 matthew 708: }
709: my @Parameters;
710: if (ref($rowdata) eq 'ARRAY') {
711: @Parameters = @$rowdata;
712: } elsif (ref($rowdata) eq 'HASH') {
1.3 matthew 713: foreach (@{$Tables{$tablename}->{'Col_order'}}) {
1.1 matthew 714: push(@Parameters,&Apache::lonnet::escape($rowdata->{$_}));
715: }
716: }
717: $sth->execute(@Parameters);
718: if ($sth->err) {
719: $errorstring = "$dbh ATTEMPTED insert @Parameters RESULTING ERROR:\n".
720: $sth->errstr;
721: return undef;
722: }
723: $debugstring = "Stored row.";
724: return 1;
725: }
726:
727: ###########################################
728:
729: =pod
730:
731: =item tables_in_db
732:
733: Returns a list containing the names of all the tables in the database.
734: Returns undef on error.
735:
736: =cut
737:
738: ###########################################
739: sub tables_in_db {
1.3 matthew 740: return undef if (!defined(&connect_to_db()));
1.1 matthew 741: my $sth=$dbh->prepare('SHOW TABLES;');
742: $sth->execute();
743: if ($sth->err) {
1.3 matthew 744: $errorstring = "$dbh ATTEMPTED:\n".'SHOW TABLES'.
745: "\nRESULTING ERROR:\n".$sth->errstr;
1.1 matthew 746: return undef;
747: }
748: my $aref = $sth->fetchall_arrayref;
749: my @table_list=();
750: foreach (@$aref) {
751: push @table_list,$_->[0];
752: }
753: $debugstring = "Got list of tables in DB: @table_list";
754: return @table_list;
755: }
756:
757: ###########################################
758:
759: =pod
760:
761: =item &translate_id
762:
763: Used internally to translate a numeric table id into a MySQL table name.
764: If the input $id contains non-numeric characters it is assumed to have
765: already been translated.
766:
767: Checks are NOT performed to see if the table actually exists.
768:
769: =cut
770:
771: ###########################################
772: sub translate_id {
773: my $id = shift;
774: # id should be a digit. If it is not a digit we assume the given id
775: # is complete and does not need to be translated.
776: return $id if ($id =~ /\D/);
777: return $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.$id;
778: }
779:
780: ###########################################
781:
782: =pod
783:
784: =item &check_table($id)
785:
786: Checks to see if the requested table exists. Returns 0 (no), 1 (yes), or
787: undef (error).
788:
789: =cut
790:
791: ###########################################
792: sub check_table {
793: my $table_id = shift;
1.3 matthew 794: return undef if (!defined(&connect_to_db()));
795: #
1.1 matthew 796: $table_id = &translate_id($table_id);
797: my @Table_list = &tables_in_db();
798: my $result = 0;
799: foreach (@Table_list) {
800: if (/^$table_id$/) {
801: $result = 1;
802: last;
803: }
804: }
805: # If it does not exist, make sure we do not have it listed in %Tables
806: delete($Tables{$table_id}) if ((! $result) && exists($Tables{$table_id}));
807: $debugstring = "check_table returned $result for $table_id";
808: return $result;
809: }
810:
811: 1;
812:
813: __END__;
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