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