1: # The LearningOnline Network with CAPA
2: # MySQL utility functions
3: #
4: # $Id: lonmysql.pm,v 1.16 2003/12/26 19:12:51 www Exp $
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: use POSIX qw(strftime mktime);
36:
37:
38: ######################################################################
39: ######################################################################
40:
41: =pod
42:
43: =head1 Name
44:
45: lonmysql - LONCAPA MySQL utility functions
46:
47: =head1 Synopsis
48:
49: lonmysql contains utility functions to make accessing the mysql loncapa
50: database easier.
51:
52: =head1 Description
53:
54: lonmysql does its best to encapsulate all the database/table functions
55: and provide a common interface. The goal, however, is not to provide
56: a complete reimplementation of the DBI interface. Instead we try to
57: make using mysql as painless as possible.
58:
59: Each table has a numeric ID that is a parameter to most lonmysql functions.
60: The table id is returned by &create_table.
61: If you lose the table id, it is lost forever.
62: The table names in MySQL correspond to
63: $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.$table_id. If the table id
64: is non-numeric, it is assumed to be the full name of a table. If you pass
65: the table id in a form, you MUST ensure that what you send to lonmysql is
66: numeric, otherwise you are opening up all the tables in the MySQL database.
67:
68: =over 4
69:
70: =item Creating a table
71:
72: To create a table, you need a description of its structure. See the entry
73: for &create_table for a description of what is needed.
74:
75: $table_id = &create_table({
76: id => 'tableid', # usually you will use the returned id
77: columns => (
78: { name => 'id',
79: type => 'INT',
80: restrictions => 'NOT NULL',
81: primary_key => 'yes',
82: auto_inc => 'yes'
83: },
84: { name => 'verbage',
85: type => 'TEXT' },
86: ),
87: fulltext => [qw/verbage/],
88: });
89:
90: The above command will create a table with two columns, 'id' and 'verbage'.
91:
92: 'id' will be an integer which is autoincremented and non-null.
93:
94: 'verbage' will be of type 'TEXT', which (conceivably) allows any length
95: text string to be stored. Depending on your intentions for this database,
96: setting restrictions => 'NOT NULL' may help you avoid storing empty data.
97:
98: the fulltext element sets up the 'verbage' column for 'FULLTEXT' searching.
99:
100:
101:
102: =item Storing rows
103:
104: Storing a row in a table requires calling &store_row($table_id,$data)
105:
106: $data is either a hash reference or an array reference. If it is an array
107: reference, the data is passed as is (after being escaped) to the
108: "INSERT INTO <table> VALUES( ... )" SQL command. If $data is a hash reference,
109: the data will be placed into an array in the proper column order for the table
110: and then passed to the database.
111:
112: An example of inserting into the table created above is:
113:
114: &store_row($table_id,[undef,'I am not a crackpot!']);
115:
116: or equivalently,
117:
118: &store_row($table_id,{ verbage => 'I am not a crackpot!'});
119:
120: Since the above table was created with the first column ('id') as
121: autoincrement, providing a value is unnecessary even though the column was
122: marked as 'NOT NULL'.
123:
124:
125:
126: =item Retrieving rows
127:
128: Retrieving rows requires calling get_rows:
129:
130: @row = &Apache::lonmysql::get_rows($table_id,$condition)
131:
132: This results in the query "SELECT * FROM <table> HAVING $condition".
133:
134: @row = &Apache::lonmysql::get_rows($table_id,'id>20');
135:
136: returns all rows with column 'id' greater than 20.
137:
138: =back
139:
140: =cut
141:
142: ######################################################################
143: ######################################################################
144: =pod
145:
146: =head1 Package Variables
147:
148: =over 4
149:
150: =cut
151:
152: ##################################################
153: ##################################################
154:
155: =pod
156:
157: =item %Tables
158:
159: Holds information regarding the currently open connections. Each key
160: in the %Tables hash will be a unique table key. The value associated
161: with a key is a hash reference. Most values are initialized when the
162: table is created.
163:
164: The following entries are allowed in the hash reference:
165:
166: =over 4
167:
168: =item Name
169:
170: Table name.
171:
172: =item Type
173:
174: The type of table, typically MyISAM.
175:
176: =item Row_format
177:
178: Describes how rows should be stored in the table. DYNAMIC or STATIC.
179:
180: =item Create_time
181:
182: The date of the tables creation.
183:
184: =item Update_time
185:
186: The date of the last modification of the table.
187:
188: =item Check_time
189:
190: Usually NULL.
191:
192: =item Avg_row_length
193:
194: The average length of the rows.
195:
196: =item Data_length
197:
198: The length of the data stored in the table (bytes)
199:
200: =item Max_data_length
201:
202: The maximum possible size of the table (bytes).
203:
204: =item Index_length
205:
206: The length of the index for the table (bytes)
207:
208: =item Data_free
209:
210: I have no idea what this is.
211:
212: =item Comment
213:
214: The comment associated with the table.
215:
216: =item Rows
217:
218: The number of rows in the table.
219:
220: =item Auto_increment
221:
222: The value of the next auto_increment field.
223:
224: =item Create_options
225:
226: I have no idea.
227:
228: =item Col_order
229:
230: an array reference which holds the order of columns in the table.
231:
232: =item row_insert_sth
233:
234: The statement handler for row inserts.
235:
236: =item row_replace_sth
237:
238: The statement handler for row inserts.
239:
240: =back
241:
242: Col_order and row_insert_sth are kept internally by lonmysql and are not
243: part of the usual MySQL table information.
244:
245: =cut
246:
247: ##################################################
248: ##################################################
249: my %Tables;
250:
251: ##################################################
252: ##################################################
253: =pod
254:
255: =item $errorstring
256:
257: Holds the last error.
258:
259: =cut
260: ##################################################
261: ##################################################
262: my $errorstring;
263:
264: ##################################################
265: ##################################################
266: =pod
267:
268: =item $debugstring
269:
270: Describes current events within the package.
271:
272: =cut
273: ##################################################
274: ##################################################
275: my $debugstring;
276:
277: ##################################################
278: ##################################################
279:
280: =pod
281:
282: =item $dbh
283:
284: The database handler; The actual connection to MySQL via the perl DBI.
285:
286: =cut
287:
288: ##################################################
289: ##################################################
290: my $dbh;
291:
292: ##################################################
293: ##################################################
294:
295: # End of global variable declarations
296:
297: =pod
298:
299: =back
300:
301: =cut
302:
303: ######################################################################
304: ######################################################################
305:
306: =pod
307:
308: =head1 Internals
309:
310: =over 4
311:
312: =cut
313:
314: ######################################################################
315: ######################################################################
316:
317: =pod
318:
319: =item &connect_to_db()
320:
321: Inputs: none.
322:
323: Returns: undef on error, 1 on success.
324:
325: Checks to make sure the database has been connected to. If not, the
326: connection is established.
327:
328: =cut
329:
330: ###############################
331: sub connect_to_db {
332: return 1 if ($dbh);
333: if (! ($dbh = DBI->connect("DBI:mysql:loncapa","www",
334: $Apache::lonnet::perlvar{'lonSqlAccess'},
335: { RaiseError=>0,PrintError=>0}))) {
336: $debugstring = "Unable to connect to loncapa database.";
337: if (! defined($dbh)) {
338: $debugstring = "Unable to connect to loncapa database.";
339: $errorstring = "dbh was undefined.";
340: } elsif ($dbh->err) {
341: $errorstring = "Connection error: ".$dbh->errstr;
342: }
343: return undef;
344: }
345: $debugstring = "Successfully connected to loncapa database.";
346: return 1;
347: }
348:
349: ###############################
350:
351: =pod
352:
353: =item &verify_sql_connection()
354:
355: Inputs: none.
356:
357: Returns: 0 (failure) or 1 (success)
358:
359: Checks to make sure the database can be connected to. It does not
360: initialize anything in the lonmysql package.
361:
362: =cut
363:
364: ###############################
365: sub verify_sql_connection {
366: my $connection;
367: if (! ($connection = DBI->connect("DBI:mysql:loncapa","www",
368: $Apache::lonnet::perlvar{'lonSqlAccess'},
369: { RaiseError=>0,PrintError=>0}))) {
370: return 0;
371: }
372: undef($connection);
373: return 1;
374: }
375:
376: ###############################
377:
378: =pod
379:
380: =item &disconnect_from_db()
381:
382: Inputs: none.
383:
384: Returns: Always returns 1.
385:
386: Severs the connection to the mysql database.
387:
388: =cut
389:
390: ###############################
391: sub disconnect_from_db {
392: foreach (keys(%Tables)) {
393: # Supposedly, having statement handlers running around after the
394: # database connection has been lost will cause trouble. So we
395: # kill them off just to be sure.
396: if (exists($Tables{$_}->{'row_insert_sth'})) {
397: delete($Tables{$_}->{'row_insert_sth'});
398: }
399: if (exists($Tables{$_}->{'row_replace_sth'})) {
400: delete($Tables{$_}->{'row_replace_sth'});
401: }
402: }
403: $dbh->disconnect if ($dbh);
404: $debugstring = "Disconnected from database.";
405: $dbh = undef;
406: return 1;
407: }
408:
409: ###############################
410:
411: =pod
412:
413: =item &number_of_rows()
414:
415: Input: table identifier
416:
417: Returns: the number of rows in the given table, undef on error.
418:
419: =cut
420:
421: ###############################
422: sub number_of_rows {
423: my ($table_id) = @_;
424: return undef if (! defined(&connect_to_db()));
425: return undef if (! defined(&update_table_info($table_id)));
426: return $Tables{&translate_id($table_id)}->{'Rows'};
427: }
428: ###############################
429:
430: =pod
431:
432: =item &get_dbh()
433:
434: Input: nothing
435:
436: Returns: the database handler, or undef on error.
437:
438: This routine allows the programmer to gain access to the database handler.
439: Be careful.
440:
441: =cut
442:
443: ###############################
444: sub get_dbh {
445: return undef if (! defined(&connect_to_db()));
446: return $dbh;
447: }
448:
449: ###############################
450:
451: =pod
452:
453: =item &get_error()
454:
455: Inputs: none.
456:
457: Returns: The last error reported.
458:
459: =cut
460:
461: ###############################
462: sub get_error {
463: return $errorstring;
464: }
465:
466: ###############################
467:
468: =pod
469:
470: =item &get_debug()
471:
472: Inputs: none.
473:
474: Returns: A string describing the internal state of the lonmysql package.
475:
476: =cut
477:
478: ###############################
479: sub get_debug {
480: return $debugstring;
481: }
482:
483: ###############################
484:
485: =pod
486:
487: =item &update_table_info()
488:
489: Inputs: table id
490:
491: Returns: undef on error, 1 on success.
492:
493: &update_table_info updates the %Tables hash with current information about
494: the given table.
495:
496: The default MySQL table status fields are:
497:
498: Name Type Row_format
499: Max_data_length Index_length Data_free
500: Create_time Update_time Check_time
501: Avg_row_length Data_length Comment
502: Rows Auto_increment Create_options
503:
504: Additionally, "Col_order" is updated as well.
505:
506: =cut
507:
508: ###############################
509: sub update_table_info {
510: my ($table_id) = @_;
511: return undef if (! defined(&connect_to_db()));
512: my $table_status = &check_table($table_id);
513: return undef if (! defined($table_status));
514: if (! $table_status) {
515: $errorstring = "table $table_id does not exist.";
516: return undef;
517: }
518: my $tablename = &translate_id($table_id);
519: #
520: # Get MySQLs table status information.
521: #
522: my @tabledesc = qw/
523: Name Type Row_format Rows Avg_row_length Data_length
524: Max_data_length Index_length Data_free Auto_increment
525: Create_time Update_time Check_time Create_options Comment /;
526: my $db_command = "SHOW TABLE STATUS FROM loncapa LIKE '$tablename'";
527: my $sth = $dbh->prepare($db_command);
528: $sth->execute();
529: if ($sth->err) {
530: $errorstring = "$dbh ATTEMPTED:\n".$db_command."\nRESULTING ERROR:\n".
531: $sth->errstr;
532: &disconnect_from_db();
533: return undef;
534: }
535: #
536: my @info=$sth->fetchrow_array;
537: for (my $i=0;$i<= $#info ; $i++) {
538: $Tables{$tablename}->{$tabledesc[$i]}= $info[$i];
539: }
540: #
541: # Determine the column order
542: #
543: $db_command = "DESCRIBE $tablename";
544: $sth = $dbh->prepare($db_command);
545: $sth->execute();
546: if ($sth->err) {
547: $errorstring = "$dbh ATTEMPTED:\n".$db_command."\nRESULTING ERROR:\n".
548: $sth->errstr;
549: &disconnect_from_db();
550: return undef;
551: }
552: my $aref=$sth->fetchall_arrayref;
553: $Tables{$tablename}->{'Col_order'}=[]; # Clear values.
554: # The values we want are the 'Field' entries, the first column.
555: for (my $i=0;$i< @$aref ; $i++) {
556: push @{$Tables{$tablename}->{'Col_order'}},$aref->[$i]->[0];
557: }
558: #
559: $debugstring = "Retrieved table info for $tablename";
560: return 1;
561: }
562:
563: ###############################
564:
565: =pod
566:
567: =item &create_table()
568:
569: Inputs:
570: table description
571:
572: Input formats:
573:
574: table description = {
575: permanent => 'yes' or 'no',
576: columns => [
577: { name => 'colA',
578: type => mysql type,
579: restrictions => 'NOT NULL' or empty,
580: primary_key => 'yes' or empty,
581: auto_inc => 'yes' or empty,
582: },
583: { name => 'colB',
584: ...
585: },
586: { name => 'colC',
587: ...
588: },
589: ],
590: 'PRIMARY KEY' => (index_col_name,...),
591: KEY => [{ name => 'idx_name',
592: columns => (col1,col2,..),},],
593: INDEX => [{ name => 'idx_name',
594: columns => (col1,col2,..),},],
595: UNIQUE => [{ index => 'yes',
596: name => 'idx_name',
597: columns => (col1,col2,..),},],
598: FULLTEXT => [{ index => 'yes',
599: name => 'idx_name',
600: columns => (col1,col2,..),},],
601:
602: }
603:
604: Returns:
605: undef on error, table id on success.
606:
607: =cut
608:
609: ###############################
610: sub create_table {
611: return undef if (!defined(&connect_to_db($dbh)));
612: my ($table_des)=@_;
613: #
614: # Build request to create table
615: ##################################
616: my @Columns;
617: my $col_des;
618: my $table_id;
619: if (exists($table_des->{'id'})) {
620: $table_id = $table_des->{'id'};
621: } else {
622: $table_id = &get_new_table_id();
623: }
624: my $tablename = &translate_id($table_id);
625: my $request = "CREATE TABLE IF NOT EXISTS ".$tablename." ";
626: foreach my $coldata (@{$table_des->{'columns'}}) {
627: my $column = $coldata->{'name'};
628: next if (! defined($column));
629: $col_des = '';
630: if (lc($coldata->{'type'}) =~ /(enum|set)/) { # 'enum' or 'set'
631: $col_des.=$column." ".$coldata->{'type'}."('".
632: join("', '",@{$coldata->{'values'}})."')";
633: } else {
634: $col_des.=$column." ".$coldata->{'type'};
635: if (exists($coldata->{'size'})) {
636: $col_des.="(".$coldata->{'size'}.")";
637: }
638: }
639: # Modifiers
640: if (exists($coldata->{'restrictions'})){
641: $col_des.=" ".$coldata->{'restrictions'};
642: }
643: if (exists($coldata->{'default'})) {
644: $col_des.=" DEFAULT '".$coldata->{'default'}."'";
645: }
646: $col_des.=' AUTO_INCREMENT' if (exists($coldata->{'auto_inc'}) &&
647: ($coldata->{'auto_inc'} eq 'yes'));
648: $col_des.=' PRIMARY KEY' if (exists($coldata->{'primary_key'}) &&
649: ($coldata->{'primary_key'} eq 'yes'));
650: } continue {
651: # skip blank items.
652: push (@Columns,$col_des) if ($col_des ne '');
653: }
654: if (exists($table_des->{'PRIMARY KEY'})) {
655: push (@Columns,'PRIMARY KEY ('.join(',',@{$table_des->{'PRIMARY KEY'}})
656: .')');
657: }
658: #
659: foreach my $indextype ('KEY','INDEX') {
660: next if (!exists($table_des->{$indextype}));
661: foreach my $indexdescription (@{$table_des->{$indextype}}) {
662: my $text = $indextype.' ';
663: if (exists($indexdescription->{'name'})) {
664: $text .=$indexdescription->{'name'};
665: }
666: $text .= ' ('.join(',',@{$indexdescription->{'columns'}}).')';
667: push (@Columns,$text);
668: }
669: }
670: #
671: foreach my $indextype ('UNIQUE','FULLTEXT') {
672: next if (! exists($table_des->{$indextype}));
673: foreach my $indexdescription (@{$table_des->{$indextype}}) {
674: my $text = $indextype.' ';
675: if (exists($indexdescription->{'index'}) &&
676: $indexdescription->{'index'} eq 'yes') {
677: $text .= 'INDEX ';
678: }
679: if (exists($indexdescription->{'name'})) {
680: $text .=$indexdescription->{'name'};
681: }
682: $text .= ' ('.join(',',@{$indexdescription->{'columns'}}).')';
683: push (@Columns,$text);
684: }
685: }
686: #
687: $request .= "(".join(", ",@Columns).") ";
688: unless($table_des->{'permanent'} eq 'yes') {
689: $request.="COMMENT = 'temporary' ";
690: }
691: $request .= "TYPE=MYISAM";
692: #
693: # Execute the request to create the table
694: #############################################
695: my $count = $dbh->do($request);
696: if (! defined($count)) {
697: $errorstring = "$dbh ATTEMPTED:\n".$request."\nRESULTING ERROR:\n";
698: return undef;
699: }
700: #
701: # Set up the internal bookkeeping
702: #############################################
703: delete($Tables{$tablename}) if (exists($Tables{$tablename}));
704: return undef if (! defined(&update_table_info($table_id)));
705: $debugstring = "Created table $tablename at time ".time.
706: " with request\n$request";
707: return $table_id;
708: }
709:
710: ###############################
711:
712: =pod
713:
714: =item &get_new_table_id()
715:
716: Used internally to prevent table name collisions.
717:
718: =cut
719:
720: ###############################
721: sub get_new_table_id {
722: my $newid = 0;
723: my @tables = &tables_in_db();
724: foreach (@tables) {
725: if (/^$ENV{'user.name'}_$ENV{'user.domain'}_(\d+)$/) {
726: $newid = $1 if ($1 > $newid);
727: }
728: }
729: return ++$newid;
730: }
731:
732: ###############################
733:
734: =pod
735:
736: =item &get_rows()
737:
738: Inputs: $table_id,$condition
739:
740: Returns: undef on error, an array ref to (array of) results on success.
741:
742: Internally, this function does a 'SELECT * FROM table WHERE $condition'.
743: $condition = 'id>0' will result in all rows where column 'id' has a value
744: greater than 0 being returned.
745:
746: =cut
747:
748: ###############################
749: sub get_rows {
750: my ($table_id,$condition) = @_;
751: return undef if (! defined(&connect_to_db()));
752: my $table_status = &check_table($table_id);
753: return undef if (! defined($table_status));
754: if (! $table_status) {
755: $errorstring = "table $table_id does not exist.";
756: return undef;
757: }
758: my $tablename = &translate_id($table_id);
759: my $request;
760: if (defined($condition) && $condition ne '') {
761: $request = 'SELECT * FROM '.$tablename.' WHERE '.$condition;
762: } else {
763: $request = 'SELECT * FROM '.$tablename;
764: $condition = 'no condition';
765: }
766: my $sth=$dbh->prepare($request);
767: $sth->execute();
768: if ($sth->err) {
769: $errorstring = "$dbh ATTEMPTED:\n".$request."\nRESULTING ERROR:\n".
770: $sth->errstr;
771: $debugstring = "Failed to get rows matching $condition";
772: return undef;
773: }
774: $debugstring = "Got rows matching $condition";
775: my @Results = @{$sth->fetchall_arrayref};
776: return @Results;
777: }
778:
779: ###############################
780:
781: =pod
782:
783: =item &store_row()
784:
785: Inputs: table id, row data
786:
787: returns undef on error, 1 on success.
788:
789: =cut
790:
791: ###############################
792: sub store_row {
793: my ($table_id,$rowdata) = @_;
794: #
795: return undef if (! defined(&connect_to_db()));
796: my $table_status = &check_table($table_id);
797: return undef if (! defined($table_status));
798: if (! $table_status) {
799: $errorstring = "table $table_id does not exist.";
800: return undef;
801: }
802: #
803: my $tablename = &translate_id($table_id);
804: #
805: my $sth;
806: if (exists($Tables{$tablename}->{'row_insert_sth'})) {
807: $sth = $Tables{$tablename}->{'row_insert_sth'};
808: } else {
809: # Build the insert statement handler
810: return undef if (! defined(&update_table_info($table_id)));
811: my $insert_request = 'INSERT INTO '.$tablename.' VALUES(';
812: foreach (@{$Tables{$tablename}->{'Col_order'}}) {
813: $insert_request.="?,";
814: }
815: chop $insert_request;
816: $insert_request.=")";
817: $sth=$dbh->prepare($insert_request);
818: $Tables{$tablename}->{'row_insert_sth'}=$sth;
819: }
820: my @Parameters;
821: if (ref($rowdata) eq 'ARRAY') {
822: @Parameters = @$rowdata;
823: } elsif (ref($rowdata) eq 'HASH') {
824: foreach (@{$Tables{$tablename}->{'Col_order'}}) {
825: push(@Parameters,$rowdata->{$_});
826: }
827: }
828: $sth->execute(@Parameters);
829: if ($sth->err) {
830: $errorstring = "$dbh ATTEMPTED insert @Parameters RESULTING ERROR:\n".
831: $sth->errstr;
832: return undef;
833: }
834: $debugstring = "Stored row.";
835: return 1;
836: }
837:
838: ###############################
839:
840: =pod
841:
842: =item &replace_row()
843:
844: Inputs: table id, row data
845:
846: returns undef on error, 1 on success.
847:
848: Acts like &store_row() but uses the 'REPLACE' command instead of 'INSERT'.
849:
850: =cut
851:
852: ###############################
853: sub replace_row {
854: my ($table_id,$rowdata) = @_;
855: #
856: return undef if (! defined(&connect_to_db()));
857: my $table_status = &check_table($table_id);
858: return undef if (! defined($table_status));
859: if (! $table_status) {
860: $errorstring = "table $table_id does not exist.";
861: return undef;
862: }
863: #
864: my $tablename = &translate_id($table_id);
865: #
866: my $sth;
867: if (exists($Tables{$tablename}->{'row_replace_sth'})) {
868: $sth = $Tables{$tablename}->{'row_replace_sth'};
869: } else {
870: # Build the insert statement handler
871: return undef if (! defined(&update_table_info($table_id)));
872: my $replace_request = 'REPLACE INTO '.$tablename.' VALUES(';
873: foreach (@{$Tables{$tablename}->{'Col_order'}}) {
874: $replace_request.="?,";
875: }
876: chop $replace_request;
877: $replace_request.=")";
878: $sth=$dbh->prepare($replace_request);
879: $Tables{$tablename}->{'row_replace_sth'}=$sth;
880: }
881: my @Parameters;
882: if (ref($rowdata) eq 'ARRAY') {
883: @Parameters = @$rowdata;
884: } elsif (ref($rowdata) eq 'HASH') {
885: foreach (@{$Tables{$tablename}->{'Col_order'}}) {
886: push(@Parameters,$rowdata->{$_});
887: }
888: }
889: $sth->execute(@Parameters);
890: if ($sth->err) {
891: $errorstring = "$dbh ATTEMPTED replace @Parameters RESULTING ERROR:\n".
892: $sth->errstr;
893: return undef;
894: }
895: $debugstring = "Stored row.";
896: return 1;
897: }
898:
899: ###########################################
900:
901: =pod
902:
903: =item &tables_in_db()
904:
905: Returns a list containing the names of all the tables in the database.
906: Returns undef on error.
907:
908: =cut
909:
910: ###########################################
911: sub tables_in_db {
912: return undef if (!defined(&connect_to_db()));
913: my $sth=$dbh->prepare('SHOW TABLES');
914: $sth->execute();
915: if ($sth->err) {
916: $errorstring = "$dbh ATTEMPTED:\n".'SHOW TABLES'.
917: "\nRESULTING ERROR:\n".$sth->errstr;
918: return undef;
919: }
920: my $aref = $sth->fetchall_arrayref;
921: my @table_list=();
922: foreach (@$aref) {
923: push @table_list,$_->[0];
924: }
925: $debugstring = "Got list of tables in DB: @table_list";
926: return @table_list;
927: }
928:
929: ###########################################
930:
931: =pod
932:
933: =item &translate_id()
934:
935: Used internally to translate a numeric table id into a MySQL table name.
936: If the input $id contains non-numeric characters it is assumed to have
937: already been translated.
938:
939: Checks are NOT performed to see if the table actually exists.
940:
941: =cut
942:
943: ###########################################
944: sub translate_id {
945: my $id = shift;
946: # id should be a digit. If it is not a digit we assume the given id
947: # is complete and does not need to be translated.
948: return $id if ($id =~ /\D/);
949: return $ENV{'user.name'}.'_'.$ENV{'user.domain'}.'_'.$id;
950: }
951:
952: ###########################################
953:
954: =pod
955:
956: =item &check_table()
957:
958: Input: table id
959:
960: Checks to see if the requested table exists. Returns 0 (no), 1 (yes), or
961: undef (error).
962:
963: =cut
964:
965: ###########################################
966: sub check_table {
967: my $table_id = shift;
968: return undef if (!defined(&connect_to_db()));
969: #
970: $table_id = &translate_id($table_id);
971: my @Table_list = &tables_in_db();
972: my $result = 0;
973: foreach (@Table_list) {
974: if ($_ eq $table_id) {
975: $result = 1;
976: last;
977: }
978: }
979: # If it does not exist, make sure we do not have it listed in %Tables
980: delete($Tables{$table_id}) if ((! $result) && exists($Tables{$table_id}));
981: $debugstring = "check_table returned $result for $table_id";
982: return $result;
983: }
984:
985: ###########################################
986:
987: =pod
988:
989: =item &remove_from_table()
990:
991: Input: $table_id, $column, $value
992:
993: Returns: the number of rows deleted. undef on error.
994:
995: Executes a "delete from $tableid where $column like binary '$value'".
996:
997: =cut
998:
999: ###########################################
1000: sub remove_from_table {
1001: my ($table_id,$column,$value) = @_;
1002: return undef if (!defined(&connect_to_db()));
1003: #
1004: $table_id = &translate_id($table_id);
1005: my $command = 'DELETE FROM '.$table_id.' WHERE '.$dbh->quote($column).
1006: " LIKE BINARY ".$dbh->quote($value);
1007: my $sth = $dbh->prepare($command);
1008: $sth->execute();
1009: if ($sth->err) {
1010: $errorstring = "ERROR on execution of ".$command."\n".$sth->errstr;
1011: return undef;
1012: }
1013: $debugstring = $command;
1014: my $rows = $sth->rows;
1015: return $rows;
1016: }
1017:
1018: ###########################################
1019:
1020: =pod
1021:
1022: =item drop_table($table_id)
1023:
1024: Issues a 'drop table if exists' command
1025:
1026: =cut
1027:
1028: ###########################################
1029:
1030: sub drop_table {
1031: my ($table_id) = @_;
1032: return undef if (!defined(&connect_to_db()));
1033: #
1034: $table_id = &translate_id($table_id);
1035: my $command = 'DROP TABLE IF EXISTS '.$table_id;
1036: my $sth = $dbh->prepare($command);
1037: $sth->execute();
1038: if ($sth->err) {
1039: $errorstring = "ERROR on execution of ".$command."\n".$sth->errstr;
1040: return undef;
1041: }
1042: $debugstring = $command;
1043: delete($Tables{$table_id}); # remove any knowledge of the table
1044: return 1; # if we got here there was no error, so return a 'true' value
1045: }
1046:
1047:
1048:
1049:
1050: # ---------------------------- convert 'time' format into a datetime sql format
1051: sub sqltime {
1052: my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
1053: localtime(&unsqltime($_[0]));
1054: $mon++; $year+=1900;
1055: return "$year-$mon-$mday $hour:$min:$sec";
1056: }
1057:
1058: sub maketime {
1059: my %th=@_;
1060: return POSIX::mktime(($th{'seconds'},$th{'minutes'},$th{'hours'},
1061: $th{'day'},$th{'month'}-1,
1062: $th{'year'}-1900,0,0,$th{'dlsav'}));
1063: }
1064:
1065:
1066: #########################################
1067: #
1068: # Retro-fixing of un-backward-compatible time format
1069:
1070: sub unsqltime {
1071: my $timestamp=shift;
1072: if ($timestamp=~/^(\d+)\-(\d+)\-(\d+)\s+(\d+)\:(\d+)\:(\d+)$/) {
1073: $timestamp=&maketime('year'=>$1,'month'=>$2,'day'=>$3,
1074: 'hours'=>$4,'minutes'=>$5,'seconds'=>$6);
1075: }
1076: return $timestamp;
1077: }
1078:
1079:
1080: 1;
1081:
1082: __END__;
1083:
1084: =pod
1085:
1086: =back
1087:
1088: =cut
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