includes/db/DatabaseIbm_db2.php

   1 <?php
   2 /**
   3  * This script is the IBM DB2 database abstraction layer
   4  *
   5  * See maintenance/ibm_db2/README for development notes and other specific information
   6  * @ingroup Database
   7  * @file
   8  * @author leo.petr+mediawiki@gmail.com
   9  */
  10
  11 /**
  12  * This represents a column in a DB2 database
  13  * @ingroup Database
  14  */
  15 class IBM_DB2Field {
  16         private $name = '';
  17         private $tablename = '';
  18         private $type = '';
  19         private $nullable = false;
  20         private $max_length = 0;
  21
  22         /**
  23          * Builder method for the class
  24          * @param DatabaseIbm_db2 $db Database interface
  25          * @param string $table table name
  26          * @param string $field column name
  27          * @return IBM_DB2Field
  28          */
  29         static function fromText($db, $table, $field) {
  30                 global $wgDBmwschema;
  31
  32                 $q = <<<END
  33 SELECT
  34 lcase(coltype) AS typname,
  35 nulls AS attnotnull, length AS attlen
  36 FROM sysibm.syscolumns
  37 WHERE tbcreator=%s AND tbname=%s AND name=%s;
  38 END;
  39                 $res = $db->query(sprintf($q,
  40                                 $db->addQuotes($wgDBmwschema),
  41                                 $db->addQuotes($table),
  42                                 $db->addQuotes($field)));
  43                 $row = $db->fetchObject($res);
  44                 if (!$row)
  45                         return null;
  46                 $n = new IBM_DB2Field;
  47                 $n->type = $row->typname;
  48                 $n->nullable = ($row->attnotnull == 'N');
  49                 $n->name = $field;
  50                 $n->tablename = $table;
  51                 $n->max_length = $row->attlen;
  52                 return $n;
  53         }
  54         /**
  55          * Get column name
  56          * @return string column name
  57          */
  58         function name() { return $this->name; }
  59         /**
  60          * Get table name
  61          * @return string table name
  62          */
  63         function tableName() { return $this->tablename; }
  64         /**
  65          * Get column type
  66          * @return string column type
  67          */
  68         function type() { return $this->type; }
  69         /**
  70          * Can column be null?
  71          * @return bool true or false
  72          */
  73         function nullable() { return $this->nullable; }
  74         /**
  75          * How much can you fit in the column per row?
  76          * @return int length
  77          */
  78         function maxLength() { return $this->max_length; }
  79 }
  80
  81 /**
  82  * Wrapper around binary large objects
  83  * @ingroup Database
  84  */
  85 class IBM_DB2Blob {
  86         private $mData;
  87
  88         function __construct($data) {
  89                 $this->mData = $data;
  90         }
  91
  92         function getData() {
  93                 return $this->mData;
  94         }
  95 }
  96
  97 /**
  98  * Primary database interface
  99  * @ingroup Database
 100  */
 101 class DatabaseIbm_db2 extends DatabaseBase {
 102         /*
 103          * Inherited members
 104         protected $mLastQuery = '';
 105         protected $mPHPError = false;
 106
 107         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 108         protected $mOut, $mOpened = false;
 109
 110         protected $mFailFunction;
 111         protected $mTablePrefix;
 112         protected $mFlags;
 113         protected $mTrxLevel = 0;
 114         protected $mErrorCount = 0;
 115         protected $mLBInfo = array();
 116         protected $mFakeSlaveLag = null, $mFakeMaster = false;
 117          *
 118          */
 119
 120         /// Server port for uncataloged connections
 121         protected $mPort = NULL;
 122         /// Whether connection is cataloged
 123         protected $mCataloged = NULL;
 124         /// Schema for tables, stored procedures, triggers
 125         protected $mSchema = NULL;
 126         /// Whether the schema has been applied in this session
 127         protected $mSchemaSet = false;
 128         /// Result of last query
 129         protected $mLastResult = NULL;
 130         /// Number of rows affected by last INSERT/UPDATE/DELETE
 131         protected $mAffectedRows = NULL;
 132         /// Number of rows returned by last SELECT
 133         protected $mNumRows = NULL;
 134
 135         /// Connection config options - see constructor
 136         public $mConnOptions = array();
 137         /// Statement config options -- see constructor
 138         public $mStmtOptions = array();
 139
 140
 141         const CATALOGED = "cataloged";
 142         const UNCATALOGED = "uncataloged";
 143         const USE_GLOBAL = "get from global";
 144
 145         const NONE_OPTION = 0x00;
 146         const CONN_OPTION = 0x01;
 147         const STMT_OPTION = 0x02;
 148
 149         const REGULAR_MODE = 'regular';
 150         const INSTALL_MODE = 'install';
 151
 152         // Whether this is regular operation or the initial installation
 153         protected $mMode = self::REGULAR_MODE;
 154
 155         /// Last sequence value used for a primary key
 156         protected $mInsertId = NULL;
 157
 158         /*
 159          * These can be safely inherited
 160          *
 161          * Getter/Setter: (18)
 162          * failFunction
 163          * setOutputPage
 164          * bufferResults
 165          * ignoreErrors
 166          * trxLevel
 167          * errorCount
 168          * getLBInfo
 169          * setLBInfo
 170          * lastQuery
 171          * isOpen
 172          * setFlag
 173          * clearFlag
 174          * getFlag
 175          * getProperty
 176          * getDBname
 177          * getServer
 178          * tableNameCallback
 179          * tablePrefix
 180          *
 181          * Administrative: (8)
 182          * debug
 183          * installErrorHandler
 184          * restoreErrorHandler
 185          * connectionErrorHandler
 186          * reportConnectionError
 187          * sourceFile
 188          * sourceStream
 189          * replaceVars
 190          *
 191          * Database: (5)
 192          * query
 193          * set
 194          * selectField
 195          * generalizeSQL
 196          * update
 197          * strreplace
 198          * deadlockLoop
 199          *
 200          * Prepared Statement: 6
 201          * prepare
 202          * freePrepared
 203          * execute
 204          * safeQuery
 205          * fillPrepared
 206          * fillPreparedArg
 207          *
 208          * Slave/Master: (4)
 209          * masterPosWait
 210          * getSlavePos
 211          * getMasterPos
 212          * getLag
 213          *
 214          * Generation: (9)
 215          * tableNames
 216          * tableNamesN
 217          * tableNamesWithUseIndexOrJOIN
 218          * escapeLike
 219          * delete
 220          * insertSelect
 221          * timestampOrNull
 222          * resultObject
 223          * aggregateValue
 224          * selectSQLText
 225          * selectRow
 226          * makeUpdateOptions
 227          *
 228          * Reflection: (1)
 229          * indexExists
 230          */
 231
 232         /*
 233          * These have been implemented
 234          *
 235          * Administrative: 7 / 7
 236          * constructor [Done]
 237          * open [Done]
 238          * openCataloged [Done]
 239          * close [Done]
 240          * newFromParams [Done]
 241          * openUncataloged [Done]
 242          * setup_database [Done]
 243          *
 244          * Getter/Setter: 13 / 13
 245          * cascadingDeletes [Done]
 246          * cleanupTriggers  [Done]
 247          * strictIPs  [Done]
 248          * realTimestamps  [Done]
 249          * impliciGroupby  [Done]
 250          * implicitOrderby  [Done]
 251          * searchableIPs  [Done]
 252          * functionalIndexes  [Done]
 253          * getWikiID  [Done]
 254          * isOpen [Done]
 255          * getServerVersion [Done]
 256          * getSoftwareLink [Done]
 257          * getSearchEngine [Done]
 258          *
 259          * Database driver wrapper: 23 / 23
 260          * lastError [Done]
 261          * lastErrno [Done]
 262          * doQuery [Done]
 263          * tableExists [Done]
 264          * fetchObject [Done]
 265          * fetchRow [Done]
 266          * freeResult [Done]
 267          * numRows [Done]
 268          * numFields [Done]
 269          * fieldName [Done]
 270          * insertId [Done]
 271          * dataSeek [Done]
 272          * affectedRows [Done]
 273          * selectDB [Done]
 274          * strencode [Done]
 275          * conditional [Done]
 276          * wasDeadlock [Done]
 277          * ping [Done]
 278          * getStatus [Done]
 279          * setTimeout [Done]
 280          * lock [Done]
 281          * unlock [Done]
 282          * insert [Done]
 283          * select [Done]
 284          *
 285          * Slave/master: 2 / 2
 286          * setFakeSlaveLag [Done]
 287          * setFakeMaster [Done]
 288          *
 289          * Reflection: 6 / 6
 290          * fieldExists [Done]
 291          * indexInfo [Done]
 292          * fieldInfo [Done]
 293          * fieldType [Done]
 294          * indexUnique [Done]
 295          * textFieldSize [Done]
 296          *
 297          * Generation: 16 / 16
 298          * tableName [Done]
 299          * addQuotes [Done]
 300          * makeList [Done]
 301          * makeSelectOptions [Done]
 302          * estimateRowCount [Done]
 303          * nextSequenceValue [Done]
 304          * useIndexClause [Done]
 305          * replace [Done]
 306          * deleteJoin [Done]
 307          * lowPriorityOption [Done]
 308          * limitResult [Done]
 309          * limitResultForUpdate [Done]
 310          * timestamp [Done]
 311          * encodeBlob [Done]
 312          * decodeBlob [Done]
 313          * buildConcat [Done]
 314          */
 315
 316         ######################################
 317         # Getters and Setters
 318         ######################################
 319
 320         /**
 321          * Returns true if this database supports (and uses) cascading deletes
 322          */
 323         function cascadingDeletes() {
 324                 return true;
 325         }
 326
 327         /**
 328          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 329          */
 330         function cleanupTriggers() {
 331                 return true;
 332         }
 333
 334         /**
 335          * Returns true if this database is strict about what can be put into an IP field.
 336          * Specifically, it uses a NULL value instead of an empty string.
 337          */
 338         function strictIPs() {
 339                 return true;
 340         }
 341
 342         /**
 343          * Returns true if this database uses timestamps rather than integers
 344         */
 345         function realTimestamps() {
 346                 return true;
 347         }
 348
 349         /**
 350          * Returns true if this database does an implicit sort when doing GROUP BY
 351          */
 352         function implicitGroupby() {
 353                 return false;
 354         }
 355
 356         /**
 357          * Returns true if this database does an implicit order by when the column has an index
 358          * For example: SELECT page_title FROM page LIMIT 1
 359          */
 360         function implicitOrderby() {
 361                 return false;
 362         }
 363
 364         /**
 365          * Returns true if this database can do a native search on IP columns
 366          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 367          */
 368         function searchableIPs() {
 369                 return true;
 370         }
 371
 372         /**
 373          * Returns true if this database can use functional indexes
 374          */
 375         function functionalIndexes() {
 376                 return true;
 377         }
 378
 379         /**
 380          * Returns a unique string representing the wiki on the server
 381          */
 382         function getWikiID() {
 383                 if( $this->mSchema ) {
 384                         return "{$this->mDBname}-{$this->mSchema}";
 385                 } else {
 386                         return $this->mDBname;
 387                 }
 388         }
 389
 390
 391         ######################################
 392         # Setup
 393         ######################################
 394
 395
 396         /**
 397          *
 398          * @param string $server hostname of database server
 399          * @param string $user username
 400          * @param string $password
 401          * @param string $dbName database name on the server
 402          * @param function $failFunction (optional)
 403          * @param integer $flags database behaviour flags (optional, unused)
 404          */
 405         public function DatabaseIbm_db2($server = false, $user = false, $password = false,
 406                                                         $dbName = false, $failFunction = false, $flags = 0,
 407                                                         $schema = self::USE_GLOBAL )
 408         {
 409
 410                 global $wgOut, $wgDBmwschema;
 411                 # Can't get a reference if it hasn't been set yet
 412                 if ( !isset( $wgOut ) ) {
 413                         $wgOut = NULL;
 414                 }
 415                 $this->mOut =& $wgOut;
 416                 $this->mFailFunction = $failFunction;
 417                 $this->mFlags = DBO_TRX | $flags;
 418
 419                 if ( $schema == self::USE_GLOBAL ) {
 420                         $this->mSchema = $wgDBmwschema;
 421                 }
 422                 else {
 423                         $this->mSchema = $schema;
 424                 }
 425
 426                 // configure the connection and statement objects
 427                 $this->setDB2Option('db2_attr_case', 'DB2_CASE_LOWER', self::CONN_OPTION | self::STMT_OPTION);
 428                 $this->setDB2Option('deferred_prepare', 'DB2_DEFERRED_PREPARE_ON', self::STMT_OPTION);
 429                 $this->setDB2Option('rowcount', 'DB2_ROWCOUNT_PREFETCH_ON', self::STMT_OPTION);
 430
 431                 $this->open( $server, $user, $password, $dbName);
 432         }
 433
 434         /**
 435          * Enables options only if the ibm_db2 extension version supports them
 436          * @param string $name Name of the option in the options array
 437          * @param string $const Name of the constant holding the right option value
 438          * @param int $type Whether this is a Connection or Statement otion
 439          */
 440         private function setDB2Option($name, $const, $type) {
 441                 if (defined($const)) {
 442                         if ($type & self::CONN_OPTION) $this->mConnOptions[$name] = constant($const);
 443                         if ($type & self::STMT_OPTION) $this->mStmtOptions[$name] = constant($const);
 444                 }
 445                 else {
 446                         $this->installPrint("$const is not defined. ibm_db2 version is likely too low.");
 447                 }
 448         }
 449
 450         /**
 451          * Outputs debug information in the appropriate place
 452          * @param string $string The relevant debug message
 453          */
 454         private function installPrint($string) {
 455                 wfDebug("$string");
 456                 if ($this->mMode == self::INSTALL_MODE) {
 457                         print "<li>$string</li>";
 458                         flush();
 459                 }
 460         }
 461
 462         /**
 463          * Opens a database connection and returns it
 464          * Closes any existing connection
 465          * @return a fresh connection
 466          * @param string $server hostname
 467          * @param string $user
 468          * @param string $password
 469          * @param string $dbName database name
 470          */
 471         public function open( $server, $user, $password, $dbName )
 472         {
 473                 // Load the port number
 474                 global $wgDBport_db2, $wgDBcataloged;
 475                 wfProfileIn( __METHOD__ );
 476
 477                 // Load IBM DB2 driver if missing
 478                 if (!@extension_loaded('ibm_db2')) {
 479                         @dl('ibm_db2.so');
 480                 }
 481                 // Test for IBM DB2 support, to avoid suppressed fatal error
 482                 if ( !function_exists( 'db2_connect' ) ) {
 483                         $error = "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?\n";
 484                         $this->installPrint($error);
 485                         $this->reportConnectionError($error);
 486                 }
 487
 488                 if (!strlen($user)) { // Copied from Postgres
 489                         return null;
 490                 }
 491
 492                 // Close existing connection
 493                 $this->close();
 494                 // Cache conn info
 495                 $this->mServer = $server;
 496                 $this->mPort = $port = $wgDBport_db2;
 497                 $this->mUser = $user;
 498                 $this->mPassword = $password;
 499                 $this->mDBname = $dbName;
 500                 $this->mCataloged = $cataloged = $wgDBcataloged;
 501
 502                 if ( $cataloged == self::CATALOGED ) {
 503                         $this->openCataloged($dbName, $user, $password);
 504                 }
 505                 elseif ( $cataloged == self::UNCATALOGED ) {
 506                         $this->openUncataloged($dbName, $user, $password, $server, $port);
 507                 }
 508                 // Apply connection config
 509                 db2_set_option($this->mConn, $this->mConnOptions, 1);
 510                 // Not all MediaWiki code is transactional
 511                 // Rather, turn autocommit off in the begin function and turn on after a commit
 512                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 513
 514                 if ( $this->mConn == false ) {
 515                         $this->installPrint( "DB connection error\n" );
 516                         $this->installPrint( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 517                         $this->installPrint( $this->lastError()."\n" );
 518                         return null;
 519                 }
 520
 521                 $this->mOpened = true;
 522                 $this->applySchema();
 523
 524                 wfProfileOut( __METHOD__ );
 525                 return $this->mConn;
 526         }
 527
 528         /**
 529          * Opens a cataloged database connection, sets mConn
 530          */
 531         protected function openCataloged( $dbName, $user, $password )
 532         {
 533                 @$this->mConn = db2_connect($dbName, $user, $password);
 534         }
 535
 536         /**
 537          * Opens an uncataloged database connection, sets mConn
 538          */
 539         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 540         {
 541                 $str = "DRIVER={IBM DB2 ODBC DRIVER};";
 542                 $str .= "DATABASE=$dbName;";
 543                 $str .= "HOSTNAME=$server;";
 544                 if ($port) $str .= "PORT=$port;";
 545                 $str .= "PROTOCOL=TCPIP;";
 546                 $str .= "UID=$user;";
 547                 $str .= "PWD=$password;";
 548
 549                 @$this->mConn = db2_connect($str, $user, $password);
 550         }
 551
 552         /**
 553          * Closes a database connection, if it is open
 554          * Returns success, true if already closed
 555          */
 556         public function close() {
 557                 $this->mOpened = false;
 558                 if ( $this->mConn ) {
 559                         if ($this->trxLevel() > 0) {
 560                                 $this->commit();
 561                         }
 562                         return db2_close( $this->mConn );
 563                 }
 564                 else {
 565                         return true;
 566                 }
 567         }
 568
 569         /**
 570          * Returns a fresh instance of this class
 571          * @static
 572          * @return
 573          * @param string $server hostname of database server
 574          * @param string $user username
 575          * @param string $password
 576          * @param string $dbName database name on the server
 577          * @param function $failFunction (optional)
 578          * @param integer $flags database behaviour flags (optional, unused)
 579          */
 580         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0)
 581         {
 582                 return new DatabaseIbm_db2( $server, $user, $password, $dbName, $failFunction, $flags );
 583         }
 584
 585         /**
 586          * Retrieves the most current database error
 587          * Forces a database rollback
 588          */
 589         public function lastError() {
 590                 $connerr = db2_conn_errormsg();
 591                 if ($connerr) {
 592                         //$this->rollback();
 593                         return $connerr;
 594                 }
 595                 $stmterr = db2_stmt_errormsg();
 596                 if ($stmterr) {
 597                         //$this->rollback();
 598                         return $stmterr;
 599                 }
 600
 601                 return false;
 602         }
 603
 604         /**
 605          * Get the last error number
 606          * Return 0 if no error
 607          * @return integer
 608          */
 609         public function lastErrno() {
 610                 $connerr = db2_conn_error();
 611                 if ($connerr) return $connerr;
 612                 $stmterr = db2_stmt_error();
 613                 if ($stmterr) return $stmterr;
 614                 return 0;
 615         }
 616
 617         /**
 618          * Is a database connection open?
 619          * @return
 620          */
 621         public function isOpen() { return $this->mOpened; }
 622
 623         /**
 624          * The DBMS-dependent part of query()
 625          * @param  $sql String: SQL query.
 626          * @return object Result object to feed to fetchObject, fetchRow, ...; or false on failure
 627          * @access private
 628          */
 629         /*private*/
 630         public function doQuery( $sql ) {
 631                 //print "<li><pre>$sql</pre></li>";
 632                 // Switch into the correct namespace
 633                 $this->applySchema();
 634
 635                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 636                 if( !$ret ) {
 637                         print "<br><pre>";
 638                         print $sql;
 639                         print "</pre><br>";
 640                         $error = db2_stmt_errormsg();
 641                         throw new DBUnexpectedError($this,  'SQL error: ' . htmlspecialchars( $error ) );
 642                 }
 643                 $this->mLastResult = $ret;
 644                 $this->mAffectedRows = NULL;    // Not calculated until asked for
 645                 return $ret;
 646         }
 647
 648         /**
 649          * @return string Version information from the database
 650          */
 651         public function getServerVersion() {
 652                 $info = db2_server_info( $this->mConn );
 653                 return $info->DBMS_VER;
 654         }
 655
 656         /**
 657          * Queries whether a given table exists
 658          * @return boolean
 659          */
 660         public function tableExists( $table ) {
 661                 $schema = $this->mSchema;
 662                 $sql = <<< EOF
 663 SELECT COUNT(*) FROM SYSIBM.SYSTABLES ST
 664 WHERE ST.NAME = '$table' AND ST.CREATOR = '$schema'
 665 EOF;
 666                 $res = $this->query( $sql );
 667                 if (!$res) return false;
 668
 669                 // If the table exists, there should be one of it
 670                 @$row = $this->fetchRow($res);
 671                 $count = $row[0];
 672                 if ($count == '1' or $count == 1) {
 673                         return true;
 674                 }
 675
 676                 return false;
 677         }
 678
 679         /**
 680          * Fetch the next row from the given result object, in object form.
 681          * Fields can be retrieved with $row->fieldname, with fields acting like
 682          * member variables.
 683          *
 684          * @param $res SQL result object as returned from Database::query(), etc.
 685          * @return DB2 row object
 686          * @throws DBUnexpectedError Thrown if the database returns an error
 687          */
 688         public function fetchObject( $res ) {
 689                 if ( $res instanceof ResultWrapper ) {
 690                         $res = $res->result;
 691                 }
 692                 @$row = db2_fetch_object( $res );
 693                 if( $this->lastErrno() ) {
 694                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 695                 }
 696                 return $row;
 697         }
 698
 699         /**
 700          * Fetch the next row from the given result object, in associative array
 701          * form.  Fields are retrieved with $row['fieldname'].
 702          *
 703          * @param $res SQL result object as returned from Database::query(), etc.
 704          * @return DB2 row object
 705          * @throws DBUnexpectedError Thrown if the database returns an error
 706          */
 707         public function fetchRow( $res ) {
 708                 if ( $res instanceof ResultWrapper ) {
 709                         $res = $res->result;
 710                 }
 711                 @$row = db2_fetch_array( $res );
 712                 if ( $this->lastErrno() ) {
 713                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 714                 }
 715                 return $row;
 716         }
 717
 718         /**
 719          * Override if introduced to base Database class
 720          */
 721         public function initial_setup() {
 722                 // do nothing
 723         }
 724
 725         /**
 726          * Create tables, stored procedures, and so on
 727          */
 728         public function setup_database() {
 729                 // Timeout was being changed earlier due to mysterious crashes
 730                 // Changing it now may cause more problems than not changing it
 731                 //set_time_limit(240);
 732                 try {
 733                         // TODO: switch to root login if available
 734
 735                         // Switch into the correct namespace
 736                         $this->applySchema();
 737                         $this->begin();
 738
 739                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 740                         $res = null;
 741
 742                         // TODO: update mediawiki_version table
 743
 744                         // TODO: populate interwiki links
 745
 746                         if ($this->lastError()) {
 747                                 print "<li>Errors encountered during table creation -- rolled back</li>\n";
 748                                 print "<li>Please install again</li>\n";
 749                                 $this->rollback();
 750                         }
 751                         else {
 752                                 $this->commit();
 753                         }
 754                 }
 755                 catch (MWException $mwe)
 756                 {
 757                         print "<br><pre>$mwe</pre><br>";
 758                 }
 759         }
 760
 761         /**
 762          * Escapes strings
 763          * Doesn't escape numbers
 764          * @param string s string to escape
 765          * @return escaped string
 766          */
 767         public function addQuotes( $s ) {
 768                 //$this->installPrint("DB2::addQuotes($s)\n");
 769                 if ( is_null( $s ) ) {
 770                         return "NULL";
 771                 } else if ($s instanceof Blob) {
 772                         return "'".$s->fetch($s)."'";
 773                 }
 774                 $s = $this->strencode($s);
 775                 if ( is_numeric($s) ) {
 776                         return $s;
 777                 }
 778                 else {
 779                         return "'$s'";
 780                 }
 781         }
 782
 783         /**
 784          * Verifies that a DB2 column/field type is numeric
 785          * @return bool true if numeric
 786          * @param string $type DB2 column type
 787          */
 788         public function is_numeric_type( $type ) {
 789                 switch (strtoupper($type)) {
 790                 case 'SMALLINT':
 791                 case 'INTEGER':
 792                 case 'INT':
 793                 case 'BIGINT':
 794                 case 'DECIMAL':
 795                 case 'REAL':
 796                 case 'DOUBLE':
 797                 case 'DECFLOAT':
 798                         return true;
 799                 }
 800                 return false;
 801         }
 802
 803         /**
 804          * Alias for addQuotes()
 805          * @param string s string to escape
 806          * @return escaped string
 807          */
 808         public function strencode( $s ) {
 809                 // Bloody useless function
 810                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 811                 //  But also necessary
 812                 $s = db2_escape_string($s);
 813                 // Wide characters are evil -- some of them look like '
 814                 $s = utf8_encode($s);
 815                 // Fix its stupidity
 816                 $from = array("\\\\",   "\\'",  '\\n',  '\\t',  '\\"',  '\\r');
 817                 $to =   array("\\",             "''",   "\n",   "\t",   '"',    "\r");
 818                 $s = str_replace($from, $to, $s); // DB2 expects '', not \' escaping
 819                 return $s;
 820         }
 821
 822         /**
 823          * Switch into the database schema
 824          */
 825         protected function applySchema() {
 826                 if ( !($this->mSchemaSet) ) {
 827                         $this->mSchemaSet = true;
 828                         $this->begin();
 829                         $this->doQuery("SET SCHEMA = $this->mSchema");
 830                         $this->commit();
 831                 }
 832         }
 833
 834         /**
 835          * Start a transaction (mandatory)
 836          */
 837         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 838                 // turn off auto-commit
 839                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_OFF);
 840                 $this->mTrxLevel = 1;
 841         }
 842
 843         /**
 844          * End a transaction
 845          * Must have a preceding begin()
 846          */
 847         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 848                 db2_commit($this->mConn);
 849                 // turn auto-commit back on
 850                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 851                 $this->mTrxLevel = 0;
 852         }
 853
 854         /**
 855          * Cancel a transaction
 856          */
 857         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 858                 db2_rollback($this->mConn);
 859                 // turn auto-commit back on
 860                 // not sure if this is appropriate
 861                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 862                 $this->mTrxLevel = 0;
 863         }
 864
 865         /**
 866          * Makes an encoded list of strings from an array
 867          * $mode:
 868          *        LIST_COMMA         - comma separated, no field names
 869          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
 870          *        LIST_OR            - ORed WHERE clause (without the WHERE)
 871          *        LIST_SET           - comma separated with field names, like a SET clause
 872          *        LIST_NAMES         - comma separated field names
 873          */
 874         public function makeList( $a, $mode = LIST_COMMA ) {
 875                 if ( !is_array( $a ) ) {
 876                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
 877                 }
 878
 879                 $first = true;
 880                 $list = '';
 881                 foreach ( $a as $field => $value ) {
 882                         if ( !$first ) {
 883                                 if ( $mode == LIST_AND ) {
 884                                         $list .= ' AND ';
 885                                 } elseif($mode == LIST_OR) {
 886                                         $list .= ' OR ';
 887                                 } else {
 888                                         $list .= ',';
 889                                 }
 890                         } else {
 891                                 $first = false;
 892                         }
 893                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
 894                                 $list .= "($value)";
 895                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
 896                                 $list .= "$value";
 897                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
 898                                 if( count( $value ) == 0 ) {
 899                                         throw new MWException( __METHOD__.': empty input' );
 900                                 } elseif( count( $value ) == 1 ) {
 901                                         // Special-case single values, as IN isn't terribly efficient
 902                                         // Don't necessarily assume the single key is 0; we don't
 903                                         // enforce linear numeric ordering on other arrays here.
 904                                         $value = array_values( $value );
 905                                         $list .= $field." = ".$this->addQuotes( $value[0] );
 906                                 } else {
 907                                         $list .= $field." IN (".$this->makeList($value).") ";
 908                                 }
 909                         } elseif( is_null($value) ) {
 910                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
 911                                         $list .= "$field IS ";
 912                                 } elseif ( $mode == LIST_SET ) {
 913                                         $list .= "$field = ";
 914                                 }
 915                                 $list .= 'NULL';
 916                         } else {
 917                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
 918                                         $list .= "$field = ";
 919                                 }
 920                                 if ( $mode == LIST_NAMES ) {
 921                                         $list .= $value;
 922                                 }
 923                                 // Leo: Can't insert quoted numbers into numeric columns
 924                                 // (?) Might cause other problems. May have to check column type before insertion.
 925                                 else if ( is_numeric($value) ) {
 926                                         $list .= $value;
 927                                 }
 928                                 else {
 929                                         $list .= $this->addQuotes( $value );
 930                                 }
 931                         }
 932                 }
 933                 return $list;
 934         }
 935
 936         /**
 937          * Construct a LIMIT query with optional offset
 938          * This is used for query pages
 939          * $sql string SQL query we will append the limit too
 940          * $limit integer the SQL limit
 941          * $offset integer the SQL offset (default false)
 942          */
 943         public function limitResult($sql, $limit, $offset=false) {
 944                 if( !is_numeric($limit) ) {
 945                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
 946                 }
 947                 if( $offset ) {
 948                         $this->installPrint("Offset parameter not supported in limitResult()\n");
 949                 }
 950                 // TODO implement proper offset handling
 951                 // idea: get all the rows between 0 and offset, advance cursor to offset
 952                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 953         }
 954
 955         /**
 956          * Handle reserved keyword replacement in table names
 957          * @return
 958          * @param $name Object
 959          */
 960         public function tableName( $name ) {
 961                 # Replace reserved words with better ones
 962 //              switch( $name ) {
 963 //                      case 'user':
 964 //                              return 'mwuser';
 965 //                      case 'text':
 966 //                              return 'pagecontent';
 967 //                      default:
 968 //                              return $name;
 969 //              }
 970                 // we want maximum compatibility with MySQL schema
 971                 return $name;
 972         }
 973
 974         /**
 975          * Generates a timestamp in an insertable format
 976          * @return string timestamp value
 977          * @param timestamp $ts
 978          */
 979         public function timestamp( $ts=0 ) {
 980                 // TS_MW cannot be easily distinguished from an integer
 981                 return wfTimestamp(TS_DB2,$ts);
 982         }
 983
 984         /**
 985          * Return the next in a sequence, save the value for retrieval via insertId()
 986          * @param string seqName Name of a defined sequence in the database
 987          * @return next value in that sequence
 988          */
 989         public function nextSequenceValue( $seqName ) {
 990                 // Not using sequences in the primary schema to allow for easy third-party migration scripts
 991                 // Emulating MySQL behaviour of using NULL to signal that sequences aren't used
 992                 /*
 993                 $safeseq = preg_replace( "/'/", "''", $seqName );
 994                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 995                 $row = $this->fetchRow( $res );
 996                 $this->mInsertId = $row[0];
 997                 $this->freeResult( $res );
 998                 return $this->mInsertId;
 999                 */
1000                 return NULL;
1001         }
1002
1003         /**
1004          * This must be called after nextSequenceVal
1005          * @return Last sequence value used as a primary key
1006          */
1007         public function insertId() {
1008                 return $this->mInsertId;
1009         }
1010
1011         /**
1012          * Updates the mInsertId property with the value of the last insert into a generated column
1013          * @param string        $table          Sanitized table name
1014          * @param mixed         $primaryKey     String name of the primary key or a bool if this call is a do-nothing
1015          * @param resource      $stmt           Prepared statement resource
1016          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
1017          */
1018         private function calcInsertId($table, $primaryKey, $stmt) {
1019                 if ($primaryKey) {
1020                         $id_row = $this->fetchRow($stmt);
1021                         $this->mInsertId = $id_row[0];
1022                 }
1023         }
1024
1025         /**
1026          * INSERT wrapper, inserts an array into a table
1027          *
1028          * $args may be a single associative array, or an array of these with numeric keys,
1029          * for multi-row insert
1030          *
1031          * @param array $table   String: Name of the table to insert to.
1032          * @param array $args    Array: Items to insert into the table.
1033          * @param array $fname   String: Name of the function, for profiling
1034          * @param mixed $options String or Array. Valid options: IGNORE
1035          *
1036          * @return bool Success of insert operation. IGNORE always returns true.
1037          */
1038         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert', $options = array() ) {
1039                 if ( !count( $args ) ) {
1040                         return true;
1041                 }
1042                 // get database-specific table name (not used)
1043                 $table = $this->tableName( $table );
1044                 // format options as an array
1045                 if ( !is_array( $options ) ) $options = array( $options );
1046                 // format args as an array of arrays
1047                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
1048                         $args = array($args);
1049                 }
1050                 // prevent insertion of NULL into primary key columns
1051                 list($args, $primaryKeys) = $this->removeNullPrimaryKeys($table, $args);
1052                 // if there's only one primary key
1053                 // we'll be able to read its value after insertion
1054                 $primaryKey = false;
1055                 if (count($primaryKeys) == 1) {
1056                         $primaryKey = $primaryKeys[0];
1057                 }
1058
1059                 // get column names
1060                 $keys = array_keys( $args[0] );
1061                 $key_count = count($keys);
1062
1063                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
1064                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
1065
1066                 // assume success
1067                 $res = true;
1068                 // If we are not in a transaction, we need to be for savepoint trickery
1069                 $didbegin = 0;
1070                 if (! $this->mTrxLevel) {
1071                         $this->begin();
1072                         $didbegin = 1;
1073                 }
1074
1075                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1076                 switch($key_count) {
1077                         //case 0 impossible
1078                         case 1:
1079                                 $sql .= '(?)';
1080                                 break;
1081                         default:
1082                                 $sql .= '(?' . str_repeat(',?', $key_count-1) . ')';
1083                 }
1084                 // add logic to read back the new primary key value
1085                 if ($primaryKey) {
1086                         $sql = "SELECT $primaryKey FROM FINAL TABLE($sql)";
1087                 }
1088                 $stmt = $this->prepare($sql);
1089
1090                 // start a transaction/enter transaction mode
1091                 $this->begin();
1092
1093                 if ( !$ignore ) {
1094                         $first = true;
1095                         foreach ( $args as $row ) {
1096                                 // insert each row into the database
1097                                 $res = $res & $this->execute($stmt, $row);
1098                                 // get the last inserted value into a generated column
1099                                 $this->calcInsertId($table, $primaryKey, $stmt);
1100                         }
1101                 }
1102                 else {
1103                         $olde = error_reporting( 0 );
1104                         // For future use, we may want to track the number of actual inserts
1105                         // Right now, insert (all writes) simply return true/false
1106                         $numrowsinserted = 0;
1107
1108                         // always return true
1109                         $res = true;
1110
1111                         foreach ( $args as $row ) {
1112                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
1113                                 db2_exec($this->mConn, $overhead, $this->mStmtOptions);
1114
1115                                 $res2 = $this->execute($stmt, $row);
1116                                 // get the last inserted value into a generated column
1117                                 $this->calcInsertId($table, $primaryKey, $stmt);
1118
1119                                 $errNum = $this->lastErrno();
1120                                 if ($errNum) {
1121                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore", $this->mStmtOptions );
1122                                 }
1123                                 else {
1124                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore", $this->mStmtOptions );
1125                                         $numrowsinserted++;
1126                                 }
1127                         }
1128
1129                         $olde = error_reporting( $olde );
1130                         // Set the affected row count for the whole operation
1131                         $this->mAffectedRows = $numrowsinserted;
1132                 }
1133                 // commit either way
1134                 $this->commit();
1135
1136                 return $res;
1137         }
1138
1139         /**
1140          * Given a table name and a hash of columns with values
1141          * Removes primary key columns from the hash where the value is NULL
1142          *
1143          * @param string $table Name of the table
1144          * @param array $args Array of hashes of column names with values
1145          * @return array Tuple containing filtered array of columns, array of primary keys
1146          */
1147         private function removeNullPrimaryKeys($table, $args) {
1148                 $schema = $this->mSchema;
1149                 // find out the primary keys
1150                 $keyres = db2_primary_keys($this->mConn, null, strtoupper($schema), strtoupper($table));
1151                 $keys = array();
1152                 for ($row = $this->fetchObject($keyres); $row != null; $row = $this->fetchRow($keyres)) {
1153                         $keys[] = strtolower($row->column_name);
1154                 }
1155                 // remove primary keys
1156                 foreach ($args as $ai => $row) {
1157                         foreach ($keys as $ki => $key) {
1158                                 if ($row[$key] == NULL) {
1159                                         unset($row[$key]);
1160                                 }
1161                         }
1162                         $args[$ai] = $row;
1163                 }
1164                 // return modified hash
1165                 return array($args, $keys);
1166         }
1167
1168         /**
1169          * UPDATE wrapper, takes a condition array and a SET array
1170          *
1171          * @param string $table  The table to UPDATE
1172          * @param array  $values An array of values to SET
1173          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1174          * @param string $fname  The Class::Function calling this function
1175          *                       (for the log)
1176          * @param array  $options An array of UPDATE options, can be one or
1177          *                        more of IGNORE, LOW_PRIORITY
1178          * @return bool
1179          */
1180         public function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1181                 $table = $this->tableName( $table );
1182                 $opts = $this->makeUpdateOptions( $options );
1183                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1184                 if ( $conds != '*' ) {
1185                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1186                 }
1187                 return $this->query( $sql, $fname );
1188         }
1189
1190         /**
1191          * DELETE query wrapper
1192          *
1193          * Use $conds == "*" to delete all rows
1194          */
1195         public function delete( $table, $conds, $fname = 'Database::delete' ) {
1196                 if ( !$conds ) {
1197                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1198                 }
1199                 $table = $this->tableName( $table );
1200                 $sql = "DELETE FROM $table";
1201                 if ( $conds != '*' ) {
1202                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1203                 }
1204                 return $this->query( $sql, $fname );
1205         }
1206
1207         /**
1208          * Returns the number of rows affected by the last query or 0
1209          * @return int the number of rows affected by the last query
1210          */
1211         public function affectedRows() {
1212                 if ( !is_null( $this->mAffectedRows ) ) {
1213                         // Forced result for simulated queries
1214                         return $this->mAffectedRows;
1215                 }
1216                 if( empty( $this->mLastResult ) )
1217                         return 0;
1218                 return db2_num_rows( $this->mLastResult );
1219         }
1220
1221         /**
1222          * Simulates REPLACE with a DELETE followed by INSERT
1223          * @param $table Object
1224          * @param array $uniqueIndexes array consisting of indexes and arrays of indexes
1225          * @param array $rows Rows to insert
1226          * @param string $fname Name of the function for profiling
1227          * @return nothing
1228          */
1229         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseIbm_db2::replace' ) {
1230                 $table = $this->tableName( $table );
1231
1232                 if (count($rows)==0) {
1233                         return;
1234                 }
1235
1236                 # Single row case
1237                 if ( !is_array( reset( $rows ) ) ) {
1238                         $rows = array( $rows );
1239                 }
1240
1241                 foreach( $rows as $row ) {
1242                         # Delete rows which collide
1243                         if ( $uniqueIndexes ) {
1244                                 $sql = "DELETE FROM $table WHERE ";
1245                                 $first = true;
1246                                 foreach ( $uniqueIndexes as $index ) {
1247                                         if ( $first ) {
1248                                                 $first = false;
1249                                                 $sql .= "(";
1250                                         } else {
1251                                                 $sql .= ') OR (';
1252                                         }
1253                                         if ( is_array( $index ) ) {
1254                                                 $first2 = true;
1255                                                 foreach ( $index as $col ) {
1256                                                         if ( $first2 ) {
1257                                                                 $first2 = false;
1258                                                         } else {
1259                                                                 $sql .= ' AND ';
1260                                                         }
1261                                                         $sql .= $col.'=' . $this->addQuotes( $row[$col] );
1262                                                 }
1263                                         } else {
1264                                                 $sql .= $index.'=' . $this->addQuotes( $row[$index] );
1265                                         }
1266                                 }
1267                                 $sql .= ')';
1268                                 $this->query( $sql, $fname );
1269                         }
1270
1271                         # Now insert the row
1272                         $sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
1273                                 $this->makeList( $row, LIST_COMMA ) . ')';
1274                         $this->query( $sql, $fname );
1275                 }
1276         }
1277
1278         /**
1279          * Returns the number of rows in the result set
1280          * Has to be called right after the corresponding select query
1281          * @param object $res result set
1282          * @return int number of rows
1283          */
1284         public function numRows( $res ) {
1285                 if ( $res instanceof ResultWrapper ) {
1286                         $res = $res->result;
1287                 }
1288                 if ( $this->mNumRows ) {
1289                         return $this->mNumRows;
1290                 }
1291                 else {
1292                         return 0;
1293                 }
1294         }
1295
1296         /**
1297          * Moves the row pointer of the result set
1298          * @param object $res result set
1299          * @param int $row row number
1300          * @return success or failure
1301          */
1302         public function dataSeek( $res, $row ) {
1303                 if ( $res instanceof ResultWrapper ) {
1304                         $res = $res->result;
1305                 }
1306                 return db2_fetch_row( $res, $row );
1307         }
1308
1309         ###
1310         # Fix notices in Block.php
1311         ###
1312
1313         /**
1314          * Frees memory associated with a statement resource
1315          * @param object $res Statement resource to free
1316          * @return bool success or failure
1317          */
1318         public function freeResult( $res ) {
1319                 if ( $res instanceof ResultWrapper ) {
1320                         $res = $res->result;
1321                 }
1322                 if ( !@db2_free_result( $res ) ) {
1323                         throw new DBUnexpectedError($this,  "Unable to free DB2 result\n" );
1324                 }
1325         }
1326
1327         /**
1328          * Returns the number of columns in a resource
1329          * @param object $res Statement resource
1330          * @return Number of fields/columns in resource
1331          */
1332         public function numFields( $res ) {
1333                 if ( $res instanceof ResultWrapper ) {
1334                         $res = $res->result;
1335                 }
1336                 return db2_num_fields( $res );
1337         }
1338
1339         /**
1340          * Returns the nth column name
1341          * @param object $res Statement resource
1342          * @param int $n Index of field or column
1343          * @return string name of nth column
1344          */
1345         public function fieldName( $res, $n ) {
1346                 if ( $res instanceof ResultWrapper ) {
1347                         $res = $res->result;
1348                 }
1349                 return db2_field_name( $res, $n );
1350         }
1351
1352         /**
1353          * SELECT wrapper
1354          *
1355          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
1356          * @param mixed  $vars    Array or string, field name(s) to be retrieved
1357          * @param mixed  $conds   Array or string, condition(s) for WHERE
1358          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
1359          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1360          *                        see Database::makeSelectOptions code for list of supported stuff
1361          * @param array $join_conds Associative array of table join conditions (optional)
1362          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
1363          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
1364          */
1365         public function select( $table, $vars, $conds='', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1366         {
1367                 $res = parent::select( $table, $vars, $conds, $fname, $options, $join_conds );
1368
1369                 // We must adjust for offset
1370                 if ( isset( $options['LIMIT'] ) ) {
1371                         if ( isset ($options['OFFSET'] ) ) {
1372                                 $limit = $options['LIMIT'];
1373                                 $offset = $options['OFFSET'];
1374                         }
1375                 }
1376
1377
1378                 // DB2 does not have a proper num_rows() function yet, so we must emulate it
1379                 // DB2 9.5.3/9.5.4 and the corresponding ibm_db2 driver will introduce a working one
1380                 // Yay!
1381
1382                 // we want the count
1383                 $vars2 = array('count(*) as num_rows');
1384                 // respecting just the limit option
1385                 $options2 = array();
1386                 if ( isset( $options['LIMIT'] ) ) $options2['LIMIT'] = $options['LIMIT'];
1387                 // but don't try to emulate for GROUP BY
1388                 if ( isset( $options['GROUP BY'] ) ) return $res;
1389
1390                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2, $join_conds );
1391                 $obj = $this->fetchObject($res2);
1392                 $this->mNumRows = $obj->num_rows;
1393
1394
1395                 return $res;
1396         }
1397
1398         /**
1399          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1400          * Has limited support for per-column options (colnum => 'DISTINCT')
1401          *
1402          * @private
1403          *
1404          * @param array $options an associative array of options to be turned into
1405          *              an SQL query, valid keys are listed in the function.
1406          * @return array
1407          */
1408         function makeSelectOptions( $options ) {
1409                 $preLimitTail = $postLimitTail = '';
1410                 $startOpts = '';
1411
1412                 $noKeyOptions = array();
1413                 foreach ( $options as $key => $option ) {
1414                         if ( is_numeric( $key ) ) {
1415                                 $noKeyOptions[$option] = true;
1416                         }
1417                 }
1418
1419                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1420                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
1421                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1422
1423                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
1424
1425                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1426         }
1427
1428         /**
1429          * Returns link to IBM DB2 free download
1430          * @return string wikitext of a link to the server software's web site
1431          */
1432         public function getSoftwareLink() {
1433                 return "[http://www.ibm.com/software/data/db2/express/?s_cmp=ECDDWW01&s_tact=MediaWiki IBM DB2]";
1434         }
1435
1436         /**
1437          * Get search engine class. All subclasses of this
1438          * need to implement this if they wish to use searching.
1439          *
1440          * @return string
1441          */
1442         public function getSearchEngine() {
1443                 return "SearchIBM_DB2";
1444         }
1445
1446         /**
1447          * Did the last database access fail because of deadlock?
1448          * @return bool
1449          */
1450         public function wasDeadlock() {
1451                 // get SQLSTATE
1452                 $err = $this->lastErrno();
1453                 switch($err) {
1454                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1455                         case '57011':   // sql0904n, Resource unavailable, no rollback
1456                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1457                         $this->installPrint("In a deadlock because of SQLSTATE $err");
1458                         return true;
1459                 }
1460                 return false;
1461         }
1462
1463         /**
1464          * Ping the server and try to reconnect if it there is no connection
1465          * The connection may be closed and reopened while this happens
1466          * @return bool whether the connection exists
1467          */
1468         public function ping() {
1469                 // db2_ping() doesn't exist
1470                 // Emulate
1471                 $this->close();
1472                 if ($this->mCataloged == NULL) {
1473                         return false;
1474                 }
1475                 else if ($this->mCataloged) {
1476                         $this->mConn = $this->openCataloged($this->mDBName, $this->mUser, $this->mPassword);
1477                 }
1478                 else if (!$this->mCataloged) {
1479                         $this->mConn = $this->openUncataloged($this->mDBName, $this->mUser, $this->mPassword, $this->mServer, $this->mPort);
1480                 }
1481                 return false;
1482         }
1483         ######################################
1484         # Unimplemented and not applicable
1485         ######################################
1486         /**
1487          * Not implemented
1488          * @return string ''
1489          * @deprecated
1490          */
1491         public function getStatus( $which="%" ) { $this->installPrint('Not implemented for DB2: getStatus()'); return ''; }
1492         /**
1493          * Not implemented
1494          * TODO
1495          * @return bool true
1496          */
1497         /**
1498          * Not implemented
1499          * @deprecated
1500          */
1501         public function setFakeSlaveLag( $lag ) { $this->installPrint('Not implemented for DB2: setFakeSlaveLag()'); }
1502         /**
1503          * Not implemented
1504          * @deprecated
1505          */
1506         public function setFakeMaster( $enabled = true ) { $this->installPrint('Not implemented for DB2: setFakeMaster()'); }
1507         /**
1508          * Not implemented
1509          * @return string $sql
1510          * @deprecated
1511          */
1512         public function limitResultForUpdate($sql, $num) { $this->installPrint('Not implemented for DB2: limitResultForUpdate()'); return $sql; }
1513
1514         /**
1515          * Only useful with fake prepare like in base Database class
1516          * @return      string
1517          */
1518         public function fillPreparedArg( $matches ) { $this->installPrint('Not useful for DB2: fillPreparedArg()'); return ''; }
1519
1520         ######################################
1521         # Reflection
1522         ######################################
1523
1524         /**
1525          * Query whether a given column exists in the mediawiki schema
1526          * @param string $table name of the table
1527          * @param string $field name of the column
1528          * @param string $fname function name for logging and profiling
1529          */
1530         public function fieldExists( $table, $field, $fname = 'DatabaseIbm_db2::fieldExists' ) {
1531                 $table = $this->tableName( $table );
1532                 $schema = $this->mSchema;
1533                 $etable = preg_replace("/'/", "''", $table);
1534                 $eschema = preg_replace("/'/", "''", $schema);
1535                 $ecol = preg_replace("/'/", "''", $field);
1536                 $sql = <<<SQL
1537 SELECT 1 as fieldexists
1538 FROM sysibm.syscolumns sc
1539 WHERE sc.name='$ecol' AND sc.tbname='$etable' AND sc.tbcreator='$eschema'
1540 SQL;
1541                 $res = $this->query( $sql, $fname );
1542                 $count = $res ? $this->numRows($res) : 0;
1543                 if ($res)
1544                         $this->freeResult( $res );
1545                 return $count;
1546         }
1547
1548         /**
1549          * Returns information about an index
1550          * If errors are explicitly ignored, returns NULL on failure
1551          * @param string $table table name
1552          * @param string $index index name
1553          * @param string
1554          * @return object query row in object form
1555          */
1556         public function indexInfo( $table, $index, $fname = 'DatabaseIbm_db2::indexExists' ) {
1557                 $table = $this->tableName( $table );
1558                 $sql = <<<SQL
1559 SELECT name as indexname
1560 FROM sysibm.sysindexes si
1561 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1562 SQL;
1563                 $res = $this->query( $sql, $fname );
1564                 if ( !$res ) {
1565                         return NULL;
1566                 }
1567                 $row = $this->fetchObject( $res );
1568                 if ($row != NULL) return $row;
1569                 else return false;
1570         }
1571
1572         /**
1573          * Returns an information object on a table column
1574          * @param string $table table name
1575          * @param string $field column name
1576          * @return IBM_DB2Field
1577          */
1578         public function fieldInfo( $table, $field ) {
1579                 return IBM_DB2Field::fromText($this, $table, $field);
1580         }
1581
1582         /**
1583          * db2_field_type() wrapper
1584          * @param object $res Result of executed statement
1585          * @param mixed $index number or name of the column
1586          * @return string column type
1587          */
1588         public function fieldType( $res, $index ) {
1589                 if ( $res instanceof ResultWrapper ) {
1590                         $res = $res->result;
1591                 }
1592                 return db2_field_type( $res, $index );
1593         }
1594
1595         /**
1596          * Verifies that an index was created as unique
1597          * @param string $table table name
1598          * @param string $index index name
1599          * @param string $fnam function name for profiling
1600          * @return bool
1601          */
1602         public function indexUnique ($table, $index, $fname = 'Database::indexUnique' ) {
1603                 $table = $this->tableName( $table );
1604                 $sql = <<<SQL
1605 SELECT si.name as indexname
1606 FROM sysibm.sysindexes si
1607 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1608 AND si.uniquerule IN ('U', 'P')
1609 SQL;
1610                 $res = $this->query( $sql, $fname );
1611                 if ( !$res ) {
1612                         return null;
1613                 }
1614                 if ($this->fetchObject( $res )) {
1615                         return true;
1616                 }
1617                 return false;
1618
1619         }
1620
1621         /**
1622          * Returns the size of a text field, or -1 for "unlimited"
1623          * @param string $table table name
1624          * @param string $field column name
1625          * @return int length or -1 for unlimited
1626          */
1627         public function textFieldSize( $table, $field ) {
1628                 $table = $this->tableName( $table );
1629                 $sql = <<<SQL
1630 SELECT length as size
1631 FROM sysibm.syscolumns sc
1632 WHERE sc.name='$field' AND sc.tbname='$table' AND sc.tbcreator='$this->mSchema'
1633 SQL;
1634                 $res = $this->query($sql);
1635                 $row = $this->fetchObject($res);
1636                 $size = $row->size;
1637                 $this->freeResult( $res );
1638                 return $size;
1639         }
1640
1641         /**
1642          * DELETE where the condition is a join
1643          * @param string $delTable deleting from this table
1644          * @param string $joinTable using data from this table
1645          * @param string $delVar variable in deleteable table
1646          * @param string $joinVar variable in data table
1647          * @param array $conds conditionals for join table
1648          * @param string $fname function name for profiling
1649          */
1650         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = "DatabaseIbm_db2::deleteJoin" ) {
1651                 if ( !$conds ) {
1652                         throw new DBUnexpectedError($this,  'Database::deleteJoin() called with empty $conds' );
1653                 }
1654
1655                 $delTable = $this->tableName( $delTable );
1656                 $joinTable = $this->tableName( $joinTable );
1657                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
1658                 if ( $conds != '*' ) {
1659                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1660                 }
1661                 $sql .= ')';
1662
1663                 $this->query( $sql, $fname );
1664         }
1665
1666         /**
1667          * Description is left as an exercise for the reader
1668          * @param mixed $b data to be encoded
1669          * @return IBM_DB2Blob
1670          */
1671         public function encodeBlob($b) {
1672                 return new IBM_DB2Blob($b);
1673         }
1674
1675         /**
1676          * Description is left as an exercise for the reader
1677          * @param IBM_DB2Blob $b data to be decoded
1678          * @return mixed
1679          */
1680         public function decodeBlob($b) {
1681                 return $b->getData();
1682         }
1683
1684         /**
1685          * Convert into a list of string being concatenated
1686          * @param array $stringList strings that need to be joined together by the SQL engine
1687          * @return string joined by the concatenation operator
1688          */
1689         public function buildConcat( $stringList ) {
1690                 // || is equivalent to CONCAT
1691                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1692                 return implode( ' || ', $stringList );
1693         }
1694
1695         /**
1696          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1697          * @param string $column name of timestamp column
1698          * @return string SQL code
1699          */
1700         public function extractUnixEpoch( $column ) {
1701                 // TODO
1702                 // see SpecialAncientpages
1703         }
1704
1705         ######################################
1706         # Prepared statements
1707         ######################################
1708
1709         /**
1710          * Intended to be compatible with the PEAR::DB wrapper functions.
1711          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1712          *
1713          * ? = scalar value, quoted as necessary
1714          * ! = raw SQL bit (a function for instance)
1715          * & = filename; reads the file and inserts as a blob
1716          *     (we don't use this though...)
1717          * @param string $sql SQL statement with appropriate markers
1718          * @return resource a prepared DB2 SQL statement
1719          */
1720         public function prepare( $sql, $func = 'DB2::prepare' ) {
1721                 $stmt = db2_prepare($this->mConn, $sql, $this->mStmtOptions);
1722                 return $stmt;
1723         }
1724
1725         /**
1726          * Frees resources associated with a prepared statement
1727          * @return bool success or failure
1728          */
1729         public function freePrepared( $prepared ) {
1730                 return db2_free_stmt($prepared);
1731         }
1732
1733         /**
1734          * Execute a prepared query with the various arguments
1735          * @param       string          $prepared       the prepared sql
1736          * @param       mixed           $args           Either an array here, or put scalars as varargs
1737          * @return      resource                                Results object
1738          */
1739         public function execute( $prepared, $args = null ) {
1740                 if( !is_array( $args ) ) {
1741                         # Pull the var args
1742                         $args = func_get_args();
1743                         array_shift( $args );
1744                 }
1745                 $res = db2_execute($prepared, $args);
1746                 return $res;
1747         }
1748
1749         /**
1750          * Prepare & execute an SQL statement, quoting and inserting arguments
1751          * in the appropriate places.
1752          * @param $query String
1753          * @param $args ...
1754          */
1755         public function safeQuery( $query, $args = null ) {
1756                 // copied verbatim from Database.php
1757                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1758                 if( !is_array( $args ) ) {
1759                         # Pull the var args
1760                         $args = func_get_args();
1761                         array_shift( $args );
1762                 }
1763                 $retval = $this->execute( $prepared, $args );
1764                 $this->freePrepared( $prepared );
1765                 return $retval;
1766         }
1767
1768         /**
1769          * For faking prepared SQL statements on DBs that don't support
1770          * it directly.
1771          * @param       resource        $preparedQuery  String: a 'preparable' SQL statement
1772          * @param       array           $args                   Array of arguments to fill it with
1773          * @return      string                                          executable statement
1774          */
1775         public function fillPrepared( $preparedQuery, $args ) {
1776                 reset( $args );
1777                 $this->preparedArgs =& $args;
1778
1779                 foreach ($args as $i => $arg) {
1780                         db2_bind_param($preparedQuery, $i+1, $args[$i]);
1781                 }
1782
1783                 return $preparedQuery;
1784         }
1785
1786         /**
1787          * Switches module between regular and install modes
1788          */
1789         public function setMode($mode) {
1790                 $old =  $this->mMode;
1791                 $this->mMode = $mode;
1792                 return $old;
1793         }
1794
1795         /**
1796          * Bitwise negation of a column or value in SQL
1797          * Same as (~field) in C
1798          * @param       string  $field
1799          * @return      string
1800          */
1801         function bitNot($field) {
1802                 //expecting bit-fields smaller than 4bytes
1803                 return 'BITNOT('.$bitField.')';
1804         }
1805
1806         /**
1807          * Bitwise AND of two columns or values in SQL
1808          * Same as (fieldLeft & fieldRight) in C
1809          * @param       string  $fieldLeft
1810          * @param       string  $fieldRight
1811          * @return      string
1812          */
1813         function bitAnd($fieldLeft, $fieldRight) {
1814                 return 'BITAND('.$fieldLeft.', '.$fieldRight.')';
1815         }
1816
1817         /**
1818          * Bitwise OR of two columns or values in SQL
1819          * Same as (fieldLeft | fieldRight) in C
1820          * @param       string  $fieldLeft
1821          * @param       string  $fieldRight
1822          * @return      string
1823          */
1824         function bitOr($fieldLeft, $fieldRight) {
1825                 return 'BITOR('.$fieldLeft.', '.$fieldRight.')';
1826         }
1827 }