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: 6 / 6
 295          * fieldExists [Done]
 296          * indexInfo [Done]
 297          * fieldInfo [Done]
 298          * fieldType [Done]
 299          * indexUnique [Done]
 300          * textFieldSize [Done]
 301          *
 302          * Generation: 16 / 16
 303          * tableName [Done]
 304          * addQuotes [Done]
 305          * makeList [Done]
 306          * makeSelectOptions [Done]
 307          * estimateRowCount [Done]
 308          * nextSequenceValue [Done]
 309          * useIndexClause [Done]
 310          * replace [Done]
 311          * deleteJoin [Done]
 312          * lowPriorityOption [Done]
 313          * limitResult [Done]
 314          * limitResultForUpdate [Done]
 315          * timestamp [Done]
 316          * encodeBlob [Done]
 317          * decodeBlob [Done]
 318          * buildConcat [Done]
 319          */
 320
 321         ######################################
 322         # Getters and Setters
 323         ######################################
 324
 325         /**
 326          * Returns true if this database supports (and uses) cascading deletes
 327          */
 328         function cascadingDeletes() {
 329                 return true;
 330         }
 331
 332         /**
 333          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 334          */
 335         function cleanupTriggers() {
 336                 return true;
 337         }
 338
 339         /**
 340          * Returns true if this database is strict about what can be put into an IP field.
 341          * Specifically, it uses a NULL value instead of an empty string.
 342          */
 343         function strictIPs() {
 344                 return true;
 345         }
 346
 347         /**
 348          * Returns true if this database uses timestamps rather than integers
 349         */
 350         function realTimestamps() {
 351                 return true;
 352         }
 353
 354         /**
 355          * Returns true if this database does an implicit sort when doing GROUP BY
 356          */
 357         function implicitGroupby() {
 358                 return false;
 359         }
 360
 361         /**
 362          * Returns true if this database does an implicit order by when the column has an index
 363          * For example: SELECT page_title FROM page LIMIT 1
 364          */
 365         function implicitOrderby() {
 366                 return false;
 367         }
 368
 369         /**
 370          * Returns true if this database can do a native search on IP columns
 371          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 372          */
 373         function searchableIPs() {
 374                 return true;
 375         }
 376
 377         /**
 378          * Returns true if this database can use functional indexes
 379          */
 380         function functionalIndexes() {
 381                 return true;
 382         }
 383
 384         /**
 385          * Returns a unique string representing the wiki on the server
 386          */
 387         function getWikiID() {
 388                 if( $this->mSchema ) {
 389                         return "{$this->mDBname}-{$this->mSchema}";
 390                 } else {
 391                         return $this->mDBname;
 392                 }
 393         }
 394
 395         function getType() {
 396                 return 'ibm_db2';
 397         }
 398
 399         ######################################
 400         # Setup
 401         ######################################
 402
 403
 404         /**
 405          *
 406          * @param $server String: hostname of database server
 407          * @param $user String: username
 408          * @param $password String: password
 409          * @param $dbName String: database name on the server
 410          * @param $failFunction Callback (optional)
 411          * @param $flags Integer: database behaviour flags (optional, unused)
 412          * @param $schema String
 413          */
 414         public function DatabaseIbm_db2($server = false, $user = false, $password = false,
 415                                                         $dbName = false, $failFunction = false, $flags = 0,
 416                                                         $schema = self::USE_GLOBAL )
 417         {
 418
 419                 global $wgOut, $wgDBmwschema;
 420                 # Can't get a reference if it hasn't been set yet
 421                 if ( !isset( $wgOut ) ) {
 422                         $wgOut = null;
 423                 }
 424                 $this->mOut =& $wgOut;
 425                 $this->mFailFunction = $failFunction;
 426                 $this->mFlags = DBO_TRX | $flags;
 427
 428                 if ( $schema == self::USE_GLOBAL ) {
 429                         $this->mSchema = $wgDBmwschema;
 430                 }
 431                 else {
 432                         $this->mSchema = $schema;
 433                 }
 434
 435                 // configure the connection and statement objects
 436                 $this->setDB2Option('db2_attr_case', 'DB2_CASE_LOWER', self::CONN_OPTION | self::STMT_OPTION);
 437                 $this->setDB2Option('deferred_prepare', 'DB2_DEFERRED_PREPARE_ON', self::STMT_OPTION);
 438                 $this->setDB2Option('rowcount', 'DB2_ROWCOUNT_PREFETCH_ON', self::STMT_OPTION);
 439
 440                 $this->open( $server, $user, $password, $dbName);
 441         }
 442
 443         /**
 444          * Enables options only if the ibm_db2 extension version supports them
 445          * @param $name String: name of the option in the options array
 446          * @param $const String: name of the constant holding the right option value
 447          * @param $type Integer: whether this is a Connection or Statement otion
 448          */
 449         private function setDB2Option($name, $const, $type) {
 450                 if (defined($const)) {
 451                         if ($type & self::CONN_OPTION) $this->mConnOptions[$name] = constant($const);
 452                         if ($type & self::STMT_OPTION) $this->mStmtOptions[$name] = constant($const);
 453                 }
 454                 else {
 455                         $this->installPrint("$const is not defined. ibm_db2 version is likely too low.");
 456                 }
 457         }
 458
 459         /**
 460          * Outputs debug information in the appropriate place
 461          * @param $string String: the relevant debug message
 462          */
 463         private function installPrint($string) {
 464                 wfDebug("$string");
 465                 if ($this->mMode == self::INSTALL_MODE) {
 466                         print "<li>$string</li>";
 467                         flush();
 468                 }
 469         }
 470
 471         /**
 472          * Opens a database connection and returns it
 473          * Closes any existing connection
 474          * @return a fresh connection
 475          * @param $server String: hostname
 476          * @param $user String
 477          * @param $password String
 478          * @param $dbName String: database name
 479          */
 480         public function open( $server, $user, $password, $dbName )
 481         {
 482                 // Load the port number
 483                 global $wgDBport_db2, $wgDBcataloged;
 484                 wfProfileIn( __METHOD__ );
 485
 486                 // Load IBM DB2 driver if missing
 487                 wfDl( 'ibm_db2' );
 488
 489                 // Test for IBM DB2 support, to avoid suppressed fatal error
 490                 if ( !function_exists( 'db2_connect' ) ) {
 491                         $error = "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?\n";
 492                         $this->installPrint($error);
 493                         $this->reportConnectionError($error);
 494                 }
 495
 496                 if (!strlen($user)) { // Copied from Postgres
 497                         return null;
 498                 }
 499
 500                 // Close existing connection
 501                 $this->close();
 502                 // Cache conn info
 503                 $this->mServer = $server;
 504                 $this->mPort = $port = $wgDBport_db2;
 505                 $this->mUser = $user;
 506                 $this->mPassword = $password;
 507                 $this->mDBname = $dbName;
 508                 $this->mCataloged = $cataloged = $wgDBcataloged;
 509
 510                 if ( $cataloged == self::CATALOGED ) {
 511                         $this->openCataloged($dbName, $user, $password);
 512                 }
 513                 elseif ( $cataloged == self::UNCATALOGED ) {
 514                         $this->openUncataloged($dbName, $user, $password, $server, $port);
 515                 }
 516                 // Apply connection config
 517                 db2_set_option($this->mConn, $this->mConnOptions, 1);
 518                 // Not all MediaWiki code is transactional
 519                 // Rather, turn autocommit off in the begin function and turn on after a commit
 520                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 521
 522                 if ( !$this->mConn ) {
 523                         $this->installPrint( "DB connection error\n" );
 524                         $this->installPrint( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 525                         $this->installPrint( $this->lastError()."\n" );
 526                         return null;
 527                 }
 528
 529                 $this->mOpened = true;
 530                 $this->applySchema();
 531
 532                 wfProfileOut( __METHOD__ );
 533                 return $this->mConn;
 534         }
 535
 536         /**
 537          * Opens a cataloged database connection, sets mConn
 538          */
 539         protected function openCataloged( $dbName, $user, $password )
 540         {
 541                 @$this->mConn = db2_connect($dbName, $user, $password);
 542         }
 543
 544         /**
 545          * Opens an uncataloged database connection, sets mConn
 546          */
 547         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 548         {
 549                 $str = "DRIVER={IBM DB2 ODBC DRIVER};";
 550                 $str .= "DATABASE=$dbName;";
 551                 $str .= "HOSTNAME=$server;";
 552                 if ($port) $str .= "PORT=$port;";
 553                 $str .= "PROTOCOL=TCPIP;";
 554                 $str .= "UID=$user;";
 555                 $str .= "PWD=$password;";
 556
 557                 @$this->mConn = db2_connect($str, $user, $password);
 558         }
 559
 560         /**
 561          * Closes a database connection, if it is open
 562          * Returns success, true if already closed
 563          */
 564         public function close() {
 565                 $this->mOpened = false;
 566                 if ( $this->mConn ) {
 567                         if ($this->trxLevel() > 0) {
 568                                 $this->commit();
 569                         }
 570                         return db2_close( $this->mConn );
 571                 }
 572                 else {
 573                         return true;
 574                 }
 575         }
 576
 577         /**
 578          * Returns a fresh instance of this class
 579          *
 580          * @param $server String: hostname of database server
 581          * @param $user String: username
 582          * @param $password String
 583          * @param $dbName String: database name on the server
 584          * @param $failFunction Callback (optional)
 585          * @param $flags Integer: database behaviour flags (optional, unused)
 586          * @return DatabaseIbm_db2 object
 587          */
 588         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0)
 589         {
 590                 return new DatabaseIbm_db2( $server, $user, $password, $dbName, $failFunction, $flags );
 591         }
 592
 593         /**
 594          * Retrieves the most current database error
 595          * Forces a database rollback
 596          */
 597         public function lastError() {
 598                 $connerr = db2_conn_errormsg();
 599                 if ($connerr) {
 600                         //$this->rollback();
 601                         return $connerr;
 602                 }
 603                 $stmterr = db2_stmt_errormsg();
 604                 if ($stmterr) {
 605                         //$this->rollback();
 606                         return $stmterr;
 607                 }
 608
 609                 return false;
 610         }
 611
 612         /**
 613          * Get the last error number
 614          * Return 0 if no error
 615          * @return integer
 616          */
 617         public function lastErrno() {
 618                 $connerr = db2_conn_error();
 619                 if ($connerr) return $connerr;
 620                 $stmterr = db2_stmt_error();
 621                 if ($stmterr) return $stmterr;
 622                 return 0;
 623         }
 624
 625         /**
 626          * Is a database connection open?
 627          * @return
 628          */
 629         public function isOpen() { return $this->mOpened; }
 630
 631         /**
 632          * The DBMS-dependent part of query()
 633          * @param  $sql String: SQL query.
 634          * @return object Result object to feed to fetchObject, fetchRow, ...; or false on failure
 635          * @access private
 636          */
 637         /*private*/
 638         public function doQuery( $sql ) {
 639                 //print "<li><pre>$sql</pre></li>";
 640                 // Switch into the correct namespace
 641                 $this->applySchema();
 642
 643                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 644                 if( !$ret ) {
 645                         print "<br><pre>";
 646                         print $sql;
 647                         print "</pre><br>";
 648                         $error = db2_stmt_errormsg();
 649                         throw new DBUnexpectedError($this,  'SQL error: ' . htmlspecialchars( $error ) );
 650                 }
 651                 $this->mLastResult = $ret;
 652                 $this->mAffectedRows = null;    // Not calculated until asked for
 653                 return $ret;
 654         }
 655
 656         /**
 657          * @return string Version information from the database
 658          */
 659         public function getServerVersion() {
 660                 $info = db2_server_info( $this->mConn );
 661                 return $info->DBMS_VER;
 662         }
 663
 664         /**
 665          * Queries whether a given table exists
 666          * @return boolean
 667          */
 668         public function tableExists( $table ) {
 669                 $schema = $this->mSchema;
 670                 $sql = <<< EOF
 671 SELECT COUNT(*) FROM SYSIBM.SYSTABLES ST
 672 WHERE ST.NAME = '$table' AND ST.CREATOR = '$schema'
 673 EOF;
 674                 $res = $this->query( $sql );
 675                 if (!$res) return false;
 676
 677                 // If the table exists, there should be one of it
 678                 @$row = $this->fetchRow($res);
 679                 $count = $row[0];
 680                 if ($count == '1' or $count == 1) {
 681                         return true;
 682                 }
 683
 684                 return false;
 685         }
 686
 687         /**
 688          * Fetch the next row from the given result object, in object form.
 689          * Fields can be retrieved with $row->fieldname, with fields acting like
 690          * member variables.
 691          *
 692          * @param $res SQL result object as returned from Database::query(), etc.
 693          * @return DB2 row object
 694          * @throws DBUnexpectedError Thrown if the database returns an error
 695          */
 696         public function fetchObject( $res ) {
 697                 if ( $res instanceof ResultWrapper ) {
 698                         $res = $res->result;
 699                 }
 700                 @$row = db2_fetch_object( $res );
 701                 if( $this->lastErrno() ) {
 702                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 703                 }
 704                 return $row;
 705         }
 706
 707         /**
 708          * Fetch the next row from the given result object, in associative array
 709          * form.  Fields are retrieved with $row['fieldname'].
 710          *
 711          * @param $res SQL result object as returned from Database::query(), etc.
 712          * @return DB2 row object
 713          * @throws DBUnexpectedError Thrown if the database returns an error
 714          */
 715         public function fetchRow( $res ) {
 716                 if ( $res instanceof ResultWrapper ) {
 717                         $res = $res->result;
 718                 }
 719                 @$row = db2_fetch_array( $res );
 720                 if ( $this->lastErrno() ) {
 721                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 722                 }
 723                 return $row;
 724         }
 725
 726         /**
 727          * Override if introduced to base Database class
 728          */
 729         public function initial_setup() {
 730                 // do nothing
 731         }
 732
 733         /**
 734          * Create tables, stored procedures, and so on
 735          */
 736         public function setup_database() {
 737                 // Timeout was being changed earlier due to mysterious crashes
 738                 // Changing it now may cause more problems than not changing it
 739                 //set_time_limit(240);
 740                 try {
 741                         // TODO: switch to root login if available
 742
 743                         // Switch into the correct namespace
 744                         $this->applySchema();
 745                         $this->begin();
 746
 747                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 748                         if ($res !== true) {
 749                                 print " <b>FAILED</b>: " . htmlspecialchars( $res ) . "</li>";
 750                         } else {
 751                                 print " done</li>";
 752                         }
 753                         $res = null;
 754
 755                         // TODO: populate interwiki links
 756
 757                         if ($this->lastError()) {
 758                                 print "<li>Errors encountered during table creation -- rolled back</li>\n";
 759                                 print "<li>Please install again</li>\n";
 760                                 $this->rollback();
 761                         }
 762                         else {
 763                                 $this->commit();
 764                         }
 765                 }
 766                 catch (MWException $mwe)
 767                 {
 768                         print "<br><pre>$mwe</pre><br>";
 769                 }
 770         }
 771
 772         /**
 773          * Escapes strings
 774          * Doesn't escape numbers
 775          * @param $s String: string to escape
 776          * @return escaped string
 777          */
 778         public function addQuotes( $s ) {
 779                 //$this->installPrint("DB2::addQuotes($s)\n");
 780                 if ( is_null( $s ) ) {
 781                         return "NULL";
 782                 } else if ($s instanceof Blob) {
 783                         return "'".$s->fetch($s)."'";
 784                 } else if ($s instanceof IBM_DB2Blob) {
 785                         return "'".$this->decodeBlob($s)."'";
 786                 }
 787                 $s = $this->strencode($s);
 788                 if ( is_numeric($s) ) {
 789                         return $s;
 790                 }
 791                 else {
 792                         return "'$s'";
 793                 }
 794         }
 795
 796         /**
 797          * Verifies that a DB2 column/field type is numeric
 798          * @return bool true if numeric
 799          * @param $type String: DB2 column type
 800          */
 801         public function is_numeric_type( $type ) {
 802                 switch (strtoupper($type)) {
 803                 case 'SMALLINT':
 804                 case 'INTEGER':
 805                 case 'INT':
 806                 case 'BIGINT':
 807                 case 'DECIMAL':
 808                 case 'REAL':
 809                 case 'DOUBLE':
 810                 case 'DECFLOAT':
 811                         return true;
 812                 }
 813                 return false;
 814         }
 815
 816         /**
 817          * Alias for addQuotes()
 818          * @param $s String: string to escape
 819          * @return escaped string
 820          */
 821         public function strencode( $s ) {
 822                 // Bloody useless function
 823                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 824                 //  But also necessary
 825                 $s = db2_escape_string($s);
 826                 // Wide characters are evil -- some of them look like '
 827                 $s = utf8_encode($s);
 828                 // Fix its stupidity
 829                 $from = array("\\\\",   "\\'",  '\\n',  '\\t',  '\\"',  '\\r');
 830                 $to =   array("\\",             "''",   "\n",   "\t",   '"',    "\r");
 831                 $s = str_replace($from, $to, $s); // DB2 expects '', not \' escaping
 832                 return $s;
 833         }
 834
 835         /**
 836          * Switch into the database schema
 837          */
 838         protected function applySchema() {
 839                 if ( !($this->mSchemaSet) ) {
 840                         $this->mSchemaSet = true;
 841                         $this->begin();
 842                         $this->doQuery("SET SCHEMA = $this->mSchema");
 843                         $this->commit();
 844                 }
 845         }
 846
 847         /**
 848          * Start a transaction (mandatory)
 849          */
 850         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 851                 // turn off auto-commit
 852                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_OFF);
 853                 $this->mTrxLevel = 1;
 854         }
 855
 856         /**
 857          * End a transaction
 858          * Must have a preceding begin()
 859          */
 860         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 861                 db2_commit($this->mConn);
 862                 // turn auto-commit back on
 863                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 864                 $this->mTrxLevel = 0;
 865         }
 866
 867         /**
 868          * Cancel a transaction
 869          */
 870         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 871                 db2_rollback($this->mConn);
 872                 // turn auto-commit back on
 873                 // not sure if this is appropriate
 874                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 875                 $this->mTrxLevel = 0;
 876         }
 877
 878         /**
 879          * Makes an encoded list of strings from an array
 880          * $mode:
 881          *        LIST_COMMA         - comma separated, no field names
 882          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
 883          *        LIST_OR            - ORed WHERE clause (without the WHERE)
 884          *        LIST_SET           - comma separated with field names, like a SET clause
 885          *        LIST_NAMES         - comma separated field names
 886          */
 887         public function makeList( $a, $mode = LIST_COMMA ) {
 888                 if ( !is_array( $a ) ) {
 889                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
 890                 }
 891
 892                 $first = true;
 893                 $list = '';
 894                 foreach ( $a as $field => $value ) {
 895                         if ( !$first ) {
 896                                 if ( $mode == LIST_AND ) {
 897                                         $list .= ' AND ';
 898                                 } elseif($mode == LIST_OR) {
 899                                         $list .= ' OR ';
 900                                 } else {
 901                                         $list .= ',';
 902                                 }
 903                         } else {
 904                                 $first = false;
 905                         }
 906                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
 907                                 $list .= "($value)";
 908                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
 909                                 $list .= "$value";
 910                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
 911                                 if( count( $value ) == 0 ) {
 912                                         throw new MWException( __METHOD__.': empty input' );
 913                                 } elseif( count( $value ) == 1 ) {
 914                                         // Special-case single values, as IN isn't terribly efficient
 915                                         // Don't necessarily assume the single key is 0; we don't
 916                                         // enforce linear numeric ordering on other arrays here.
 917                                         $value = array_values( $value );
 918                                         $list .= $field." = ".$this->addQuotes( $value[0] );
 919                                 } else {
 920                                         $list .= $field." IN (".$this->makeList($value).") ";
 921                                 }
 922                         } elseif( is_null($value) ) {
 923                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
 924                                         $list .= "$field IS ";
 925                                 } elseif ( $mode == LIST_SET ) {
 926                                         $list .= "$field = ";
 927                                 }
 928                                 $list .= 'NULL';
 929                         } else {
 930                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
 931                                         $list .= "$field = ";
 932                                 }
 933                                 if ( $mode == LIST_NAMES ) {
 934                                         $list .= $value;
 935                                 }
 936                                 // Leo: Can't insert quoted numbers into numeric columns
 937                                 // (?) Might cause other problems. May have to check column type before insertion.
 938                                 else if ( is_numeric($value) ) {
 939                                         $list .= $value;
 940                                 }
 941                                 else {
 942                                         $list .= $this->addQuotes( $value );
 943                                 }
 944                         }
 945                 }
 946                 return $list;
 947         }
 948
 949         /**
 950          * Construct a LIMIT query with optional offset
 951          * This is used for query pages
 952          * @param $sql string SQL query we will append the limit too
 953          * @param $limit integer the SQL limit
 954          * @param $offset integer the SQL offset (default false)
 955          */
 956         public function limitResult($sql, $limit, $offset=false) {
 957                 if( !is_numeric($limit) ) {
 958                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
 959                 }
 960                 if( $offset ) {
 961                         $this->installPrint("Offset parameter not supported in limitResult()\n");
 962                 }
 963                 // TODO implement proper offset handling
 964                 // idea: get all the rows between 0 and offset, advance cursor to offset
 965                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 966         }
 967
 968         /**
 969          * Handle reserved keyword replacement in table names
 970          * @return
 971          * @param $name Object
 972          */
 973         public function tableName( $name ) {
 974                 # Replace reserved words with better ones
 975 //              switch( $name ) {
 976 //                      case 'user':
 977 //                              return 'mwuser';
 978 //                      case 'text':
 979 //                              return 'pagecontent';
 980 //                      default:
 981 //                              return $name;
 982 //              }
 983                 // we want maximum compatibility with MySQL schema
 984                 return $name;
 985         }
 986
 987         /**
 988          * Generates a timestamp in an insertable format
 989          * @return string timestamp value
 990          * @param $ts timestamp
 991          */
 992         public function timestamp( $ts=0 ) {
 993                 // TS_MW cannot be easily distinguished from an integer
 994                 return wfTimestamp(TS_DB2,$ts);
 995         }
 996
 997         /**
 998          * Return the next in a sequence, save the value for retrieval via insertId()
 999          * @param $seqName String: name of a defined sequence in the database
1000          * @return next value in that sequence
1001          */
1002         public function nextSequenceValue( $seqName ) {
1003                 // Not using sequences in the primary schema to allow for easy third-party migration scripts
1004                 // Emulating MySQL behaviour of using NULL to signal that sequences aren't used
1005                 /*
1006                 $safeseq = preg_replace( "/'/", "''", $seqName );
1007                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
1008                 $row = $this->fetchRow( $res );
1009                 $this->mInsertId = $row[0];
1010                 $this->freeResult( $res );
1011                 return $this->mInsertId;
1012                 */
1013                 return null;
1014         }
1015
1016         /**
1017          * This must be called after nextSequenceVal
1018          * @return Last sequence value used as a primary key
1019          */
1020         public function insertId() {
1021                 return $this->mInsertId;
1022         }
1023
1024         /**
1025          * Updates the mInsertId property with the value of the last insert into a generated column
1026          * @param $table      String: sanitized table name
1027          * @param $primaryKey Mixed: string name of the primary key or a bool if this call is a do-nothing
1028          * @param $stmt       Resource: prepared statement resource
1029          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
1030          */
1031         private function calcInsertId($table, $primaryKey, $stmt) {
1032                 if ($primaryKey) {
1033                         $id_row = $this->fetchRow($stmt);
1034                         $this->mInsertId = $id_row[0];
1035                 }
1036         }
1037
1038         /**
1039          * INSERT wrapper, inserts an array into a table
1040          *
1041          * $args may be a single associative array, or an array of these with numeric keys,
1042          * for multi-row insert
1043          *
1044          * @param $table   String: Name of the table to insert to.
1045          * @param $args    Array: Items to insert into the table.
1046          * @param $fname   String: Name of the function, for profiling
1047          * @param $options String or Array. Valid options: IGNORE
1048          *
1049          * @return bool Success of insert operation. IGNORE always returns true.
1050          */
1051         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert', $options = array() ) {
1052                 if ( !count( $args ) ) {
1053                         return true;
1054                 }
1055                 // get database-specific table name (not used)
1056                 $table = $this->tableName( $table );
1057                 // format options as an array
1058                 if ( !is_array( $options ) ) $options = array( $options );
1059                 // format args as an array of arrays
1060                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
1061                         $args = array($args);
1062                 }
1063                 // prevent insertion of NULL into primary key columns
1064                 list($args, $primaryKeys) = $this->removeNullPrimaryKeys($table, $args);
1065                 // if there's only one primary key
1066                 // we'll be able to read its value after insertion
1067                 $primaryKey = false;
1068                 if (count($primaryKeys) == 1) {
1069                         $primaryKey = $primaryKeys[0];
1070                 }
1071
1072                 // get column names
1073                 $keys = array_keys( $args[0] );
1074                 $key_count = count($keys);
1075
1076                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
1077                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
1078
1079                 // assume success
1080                 $res = true;
1081                 // If we are not in a transaction, we need to be for savepoint trickery
1082                 $didbegin = 0;
1083                 if (! $this->mTrxLevel) {
1084                         $this->begin();
1085                         $didbegin = 1;
1086                 }
1087
1088                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1089                 switch($key_count) {
1090                         //case 0 impossible
1091                         case 1:
1092                                 $sql .= '(?)';
1093                                 break;
1094                         default:
1095                                 $sql .= '(?' . str_repeat(',?', $key_count-1) . ')';
1096                 }
1097                 // add logic to read back the new primary key value
1098                 if ($primaryKey) {
1099                         $sql = "SELECT $primaryKey FROM FINAL TABLE($sql)";
1100                 }
1101                 $stmt = $this->prepare($sql);
1102
1103                 // start a transaction/enter transaction mode
1104                 $this->begin();
1105
1106                 if ( !$ignore ) {
1107                         $first = true;
1108                         foreach ( $args as $row ) {
1109                                 // insert each row into the database
1110                                 $res = $res & $this->execute($stmt, $row);
1111                                 // get the last inserted value into a generated column
1112                                 $this->calcInsertId($table, $primaryKey, $stmt);
1113                         }
1114                 }
1115                 else {
1116                         $olde = error_reporting( 0 );
1117                         // For future use, we may want to track the number of actual inserts
1118                         // Right now, insert (all writes) simply return true/false
1119                         $numrowsinserted = 0;
1120
1121                         // always return true
1122                         $res = true;
1123
1124                         foreach ( $args as $row ) {
1125                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
1126                                 db2_exec($this->mConn, $overhead, $this->mStmtOptions);
1127
1128                                 $res2 = $this->execute($stmt, $row);
1129                                 // get the last inserted value into a generated column
1130                                 $this->calcInsertId($table, $primaryKey, $stmt);
1131
1132                                 $errNum = $this->lastErrno();
1133                                 if ($errNum) {
1134                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore", $this->mStmtOptions );
1135                                 }
1136                                 else {
1137                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore", $this->mStmtOptions );
1138                                         $numrowsinserted++;
1139                                 }
1140                         }
1141
1142                         $olde = error_reporting( $olde );
1143                         // Set the affected row count for the whole operation
1144                         $this->mAffectedRows = $numrowsinserted;
1145                 }
1146                 // commit either way
1147                 $this->commit();
1148
1149                 return $res;
1150         }
1151
1152         /**
1153          * Given a table name and a hash of columns with values
1154          * Removes primary key columns from the hash where the value is NULL
1155          *
1156          * @param $table String: name of the table
1157          * @param $args Array of hashes of column names with values
1158          * @return Array: tuple containing filtered array of columns, array of primary keys
1159          */
1160         private function removeNullPrimaryKeys($table, $args) {
1161                 $schema = $this->mSchema;
1162                 // find out the primary keys
1163                 $keyres = db2_primary_keys($this->mConn, null, strtoupper($schema), strtoupper($table));
1164                 $keys = array();
1165                 for ($row = $this->fetchObject($keyres); $row != null; $row = $this->fetchRow($keyres)) {
1166                         $keys[] = strtolower($row->column_name);
1167                 }
1168                 // remove primary keys
1169                 foreach ($args as $ai => $row) {
1170                         foreach ($keys as $ki => $key) {
1171                                 if ($row[$key] == null) {
1172                                         unset($row[$key]);
1173                                 }
1174                         }
1175                         $args[$ai] = $row;
1176                 }
1177                 // return modified hash
1178                 return array($args, $keys);
1179         }
1180
1181         /**
1182          * UPDATE wrapper, takes a condition array and a SET array
1183          *
1184          * @param $table  String: The table to UPDATE
1185          * @param $values An array of values to SET
1186          * @param $conds  An array of conditions (WHERE). Use '*' to update all rows.
1187          * @param $fname  String: The Class::Function calling this function
1188          *                (for the log)
1189          * @param $options An array of UPDATE options, can be one or
1190          *                 more of IGNORE, LOW_PRIORITY
1191          * @return Boolean
1192          */
1193         public function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1194                 $table = $this->tableName( $table );
1195                 $opts = $this->makeUpdateOptions( $options );
1196                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1197                 if ( $conds != '*' ) {
1198                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1199                 }
1200                 return $this->query( $sql, $fname );
1201         }
1202
1203         /**
1204          * DELETE query wrapper
1205          *
1206          * Use $conds == "*" to delete all rows
1207          */
1208         public function delete( $table, $conds, $fname = 'Database::delete' ) {
1209                 if ( !$conds ) {
1210                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1211                 }
1212                 $table = $this->tableName( $table );
1213                 $sql = "DELETE FROM $table";
1214                 if ( $conds != '*' ) {
1215                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1216                 }
1217                 return $this->query( $sql, $fname );
1218         }
1219
1220         /**
1221          * Returns the number of rows affected by the last query or 0
1222          * @return Integer: the number of rows affected by the last query
1223          */
1224         public function affectedRows() {
1225                 if ( !is_null( $this->mAffectedRows ) ) {
1226                         // Forced result for simulated queries
1227                         return $this->mAffectedRows;
1228                 }
1229                 if( empty( $this->mLastResult ) )
1230                         return 0;
1231                 return db2_num_rows( $this->mLastResult );
1232         }
1233
1234         /**
1235          * Simulates REPLACE with a DELETE followed by INSERT
1236          * @param $table Object
1237          * @param $uniqueIndexes Array consisting of indexes and arrays of indexes
1238          * @param $rows Array: rows to insert
1239          * @param $fname String: name of the function for profiling
1240          * @return nothing
1241          */
1242         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseIbm_db2::replace' ) {
1243                 $table = $this->tableName( $table );
1244
1245                 if (count($rows)==0) {
1246                         return;
1247                 }
1248
1249                 # Single row case
1250                 if ( !is_array( reset( $rows ) ) ) {
1251                         $rows = array( $rows );
1252                 }
1253
1254                 foreach( $rows as $row ) {
1255                         # Delete rows which collide
1256                         if ( $uniqueIndexes ) {
1257                                 $sql = "DELETE FROM $table WHERE ";
1258                                 $first = true;
1259                                 foreach ( $uniqueIndexes as $index ) {
1260                                         if ( $first ) {
1261                                                 $first = false;
1262                                                 $sql .= "(";
1263                                         } else {
1264                                                 $sql .= ') OR (';
1265                                         }
1266                                         if ( is_array( $index ) ) {
1267                                                 $first2 = true;
1268                                                 foreach ( $index as $col ) {
1269                                                         if ( $first2 ) {
1270                                                                 $first2 = false;
1271                                                         } else {
1272                                                                 $sql .= ' AND ';
1273                                                         }
1274                                                         $sql .= $col.'=' . $this->addQuotes( $row[$col] );
1275                                                 }
1276                                         } else {
1277                                                 $sql .= $index.'=' . $this->addQuotes( $row[$index] );
1278                                         }
1279                                 }
1280                                 $sql .= ')';
1281                                 $this->query( $sql, $fname );
1282                         }
1283
1284                         # Now insert the row
1285                         $sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
1286                                 $this->makeList( $row, LIST_COMMA ) . ')';
1287                         $this->query( $sql, $fname );
1288                 }
1289         }
1290
1291         /**
1292          * Returns the number of rows in the result set
1293          * Has to be called right after the corresponding select query
1294          * @param $res Object result set
1295          * @return Integer: number of rows
1296          */
1297         public function numRows( $res ) {
1298                 if ( $res instanceof ResultWrapper ) {
1299                         $res = $res->result;
1300                 }
1301                 if ( $this->mNumRows ) {
1302                         return $this->mNumRows;
1303                 }
1304                 else {
1305                         return 0;
1306                 }
1307         }
1308
1309         /**
1310          * Moves the row pointer of the result set
1311          * @param $res Object: result set
1312          * @param $row Integer: row number
1313          * @return success or failure
1314          */
1315         public function dataSeek( $res, $row ) {
1316                 if ( $res instanceof ResultWrapper ) {
1317                         $res = $res->result;
1318                 }
1319                 return db2_fetch_row( $res, $row );
1320         }
1321
1322         ###
1323         # Fix notices in Block.php
1324         ###
1325
1326         /**
1327          * Frees memory associated with a statement resource
1328          * @param $res Object: statement resource to free
1329          * @return Boolean success or failure
1330          */
1331         public function freeResult( $res ) {
1332                 if ( $res instanceof ResultWrapper ) {
1333                         $res = $res->result;
1334                 }
1335                 if ( !@db2_free_result( $res ) ) {
1336                         throw new DBUnexpectedError($this,  "Unable to free DB2 result\n" );
1337                 }
1338         }
1339
1340         /**
1341          * Returns the number of columns in a resource
1342          * @param $res Object: statement resource
1343          * @return Number of fields/columns in resource
1344          */
1345         public function numFields( $res ) {
1346                 if ( $res instanceof ResultWrapper ) {
1347                         $res = $res->result;
1348                 }
1349                 return db2_num_fields( $res );
1350         }
1351
1352         /**
1353          * Returns the nth column name
1354          * @param $res Object: statement resource
1355          * @param $n Integer: Index of field or column
1356          * @return String name of nth column
1357          */
1358         public function fieldName( $res, $n ) {
1359                 if ( $res instanceof ResultWrapper ) {
1360                         $res = $res->result;
1361                 }
1362                 return db2_field_name( $res, $n );
1363         }
1364
1365         /**
1366          * SELECT wrapper
1367          *
1368          * @param $table   Array or string, table name(s) (prefix auto-added)
1369          * @param $vars    Array or string, field name(s) to be retrieved
1370          * @param $conds   Array or string, condition(s) for WHERE
1371          * @param $fname   String: calling function name (use __METHOD__) for logs/profiling
1372          * @param $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1373          *                 see Database::makeSelectOptions code for list of supported stuff
1374          * @param $join_conds Associative array of table join conditions (optional)
1375          *                    (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
1376          * @return Mixed: database result resource (feed to Database::fetchObject or whatever), or false on failure
1377          */
1378         public function select( $table, $vars, $conds='', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1379         {
1380                 $res = parent::select( $table, $vars, $conds, $fname, $options, $join_conds );
1381
1382                 // We must adjust for offset
1383                 if ( isset( $options['LIMIT'] ) ) {
1384                         if ( isset ($options['OFFSET'] ) ) {
1385                                 $limit = $options['LIMIT'];
1386                                 $offset = $options['OFFSET'];
1387                         }
1388                 }
1389
1390
1391                 // DB2 does not have a proper num_rows() function yet, so we must emulate it
1392                 // DB2 9.5.3/9.5.4 and the corresponding ibm_db2 driver will introduce a working one
1393                 // Yay!
1394
1395                 // we want the count
1396                 $vars2 = array('count(*) as num_rows');
1397                 // respecting just the limit option
1398                 $options2 = array();
1399                 if ( isset( $options['LIMIT'] ) ) $options2['LIMIT'] = $options['LIMIT'];
1400                 // but don't try to emulate for GROUP BY
1401                 if ( isset( $options['GROUP BY'] ) ) return $res;
1402
1403                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2, $join_conds );
1404                 $obj = $this->fetchObject($res2);
1405                 $this->mNumRows = $obj->num_rows;
1406
1407
1408                 return $res;
1409         }
1410
1411         /**
1412          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1413          * Has limited support for per-column options (colnum => 'DISTINCT')
1414          *
1415          * @private
1416          *
1417          * @param $options Associative array of options to be turned into
1418          *              an SQL query, valid keys are listed in the function.
1419          * @return Array
1420          */
1421         function makeSelectOptions( $options ) {
1422                 $preLimitTail = $postLimitTail = '';
1423                 $startOpts = '';
1424
1425                 $noKeyOptions = array();
1426                 foreach ( $options as $key => $option ) {
1427                         if ( is_numeric( $key ) ) {
1428                                 $noKeyOptions[$option] = true;
1429                         }
1430                 }
1431
1432                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1433                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
1434                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1435
1436                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
1437
1438                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1439         }
1440
1441         /**
1442          * Returns link to IBM DB2 free download
1443          * @return string wikitext of a link to the server software's web site
1444          */
1445         public function getSoftwareLink() {
1446                 return "[http://www.ibm.com/software/data/db2/express/?s_cmp=ECDDWW01&s_tact=MediaWiki IBM DB2]";
1447         }
1448
1449         /**
1450          * Get search engine class. All subclasses of this
1451          * need to implement this if they wish to use searching.
1452          *
1453          * @return String
1454          */
1455         public function getSearchEngine() {
1456                 return "SearchIBM_DB2";
1457         }
1458
1459         /**
1460          * Did the last database access fail because of deadlock?
1461          * @return Boolean
1462          */
1463         public function wasDeadlock() {
1464                 // get SQLSTATE
1465                 $err = $this->lastErrno();
1466                 switch($err) {
1467                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1468                         case '57011':   // sql0904n, Resource unavailable, no rollback
1469                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1470                         $this->installPrint("In a deadlock because of SQLSTATE $err");
1471                         return true;
1472                 }
1473                 return false;
1474         }
1475
1476         /**
1477          * Ping the server and try to reconnect if it there is no connection
1478          * The connection may be closed and reopened while this happens
1479          * @return Boolean: whether the connection exists
1480          */
1481         public function ping() {
1482                 // db2_ping() doesn't exist
1483                 // Emulate
1484                 $this->close();
1485                 if ($this->mCataloged == null) {
1486                         return false;
1487                 }
1488                 else if ($this->mCataloged) {
1489                         $this->mConn = $this->openCataloged($this->mDBName, $this->mUser, $this->mPassword);
1490                 }
1491                 else if (!$this->mCataloged) {
1492                         $this->mConn = $this->openUncataloged($this->mDBName, $this->mUser, $this->mPassword, $this->mServer, $this->mPort);
1493                 }
1494                 return false;
1495         }
1496         ######################################
1497         # Unimplemented and not applicable
1498         ######################################
1499         /**
1500          * Not implemented
1501          * @return string ''
1502          * @deprecated
1503          */
1504         public function getStatus( $which="%" ) { $this->installPrint('Not implemented for DB2: getStatus()'); return ''; }
1505         /**
1506          * Not implemented
1507          * TODO
1508          * @return bool true
1509          */
1510         /**
1511          * Not implemented
1512          * @deprecated
1513          */
1514         public function setFakeSlaveLag( $lag ) { $this->installPrint('Not implemented for DB2: setFakeSlaveLag()'); }
1515         /**
1516          * Not implemented
1517          * @deprecated
1518          */
1519         public function setFakeMaster( $enabled = true ) { $this->installPrint('Not implemented for DB2: setFakeMaster()'); }
1520         /**
1521          * Not implemented
1522          * @return string $sql
1523          * @deprecated
1524          */
1525         public function limitResultForUpdate($sql, $num) { $this->installPrint('Not implemented for DB2: limitResultForUpdate()'); return $sql; }
1526
1527         /**
1528          * Only useful with fake prepare like in base Database class
1529          * @return      string
1530          */
1531         public function fillPreparedArg( $matches ) { $this->installPrint('Not useful for DB2: fillPreparedArg()'); return ''; }
1532
1533         ######################################
1534         # Reflection
1535         ######################################
1536
1537         /**
1538          * Query whether a given column exists in the mediawiki schema
1539          * @param $table String: name of the table
1540          * @param $field String: name of the column
1541          * @param $fname String: function name for logging and profiling
1542          */
1543         public function fieldExists( $table, $field, $fname = 'DatabaseIbm_db2::fieldExists' ) {
1544                 $table = $this->tableName( $table );
1545                 $schema = $this->mSchema;
1546                 $etable = preg_replace("/'/", "''", $table);
1547                 $eschema = preg_replace("/'/", "''", $schema);
1548                 $ecol = preg_replace("/'/", "''", $field);
1549                 $sql = <<<SQL
1550 SELECT 1 as fieldexists
1551 FROM sysibm.syscolumns sc
1552 WHERE sc.name='$ecol' AND sc.tbname='$etable' AND sc.tbcreator='$eschema'
1553 SQL;
1554                 $res = $this->query( $sql, $fname );
1555                 $count = $res ? $this->numRows($res) : 0;
1556                 if ($res)
1557                         $this->freeResult( $res );
1558                 return $count;
1559         }
1560
1561         /**
1562          * Returns information about an index
1563          * If errors are explicitly ignored, returns NULL on failure
1564          * @param $table String: table name
1565          * @param $index String: index name
1566          * @param $fname String: function name for logging and profiling
1567          * @return Object query row in object form
1568          */
1569         public function indexInfo( $table, $index, $fname = 'DatabaseIbm_db2::indexExists' ) {
1570                 $table = $this->tableName( $table );
1571                 $sql = <<<SQL
1572 SELECT name as indexname
1573 FROM sysibm.sysindexes si
1574 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1575 SQL;
1576                 $res = $this->query( $sql, $fname );
1577                 if ( !$res ) {
1578                         return null;
1579                 }
1580                 $row = $this->fetchObject( $res );
1581                 if ($row != null) return $row;
1582                 else return false;
1583         }
1584
1585         /**
1586          * Returns an information object on a table column
1587          * @param $table String: table name
1588          * @param $field String: column name
1589          * @return IBM_DB2Field
1590          */
1591         public function fieldInfo( $table, $field ) {
1592                 return IBM_DB2Field::fromText($this, $table, $field);
1593         }
1594
1595         /**
1596          * db2_field_type() wrapper
1597          * @param $res Object: result of executed statement
1598          * @param $index Mixed: number or name of the column
1599          * @return String column type
1600          */
1601         public function fieldType( $res, $index ) {
1602                 if ( $res instanceof ResultWrapper ) {
1603                         $res = $res->result;
1604                 }
1605                 return db2_field_type( $res, $index );
1606         }
1607
1608         /**
1609          * Verifies that an index was created as unique
1610          * @param $table String: table name
1611          * @param $index String: index name
1612          * @param $fname function name for profiling
1613          * @return Bool
1614          */
1615         public function indexUnique ($table, $index, $fname = 'Database::indexUnique' ) {
1616                 $table = $this->tableName( $table );
1617                 $sql = <<<SQL
1618 SELECT si.name as indexname
1619 FROM sysibm.sysindexes si
1620 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1621 AND si.uniquerule IN ('U', 'P')
1622 SQL;
1623                 $res = $this->query( $sql, $fname );
1624                 if ( !$res ) {
1625                         return null;
1626                 }
1627                 if ($this->fetchObject( $res )) {
1628                         return true;
1629                 }
1630                 return false;
1631
1632         }
1633
1634         /**
1635          * Returns the size of a text field, or -1 for "unlimited"
1636          * @param $table String: table name
1637          * @param $field String: column name
1638          * @return Integer: length or -1 for unlimited
1639          */
1640         public function textFieldSize( $table, $field ) {
1641                 $table = $this->tableName( $table );
1642                 $sql = <<<SQL
1643 SELECT length as size
1644 FROM sysibm.syscolumns sc
1645 WHERE sc.name='$field' AND sc.tbname='$table' AND sc.tbcreator='$this->mSchema'
1646 SQL;
1647                 $res = $this->query($sql);
1648                 $row = $this->fetchObject($res);
1649                 $size = $row->size;
1650                 $this->freeResult( $res );
1651                 return $size;
1652         }
1653
1654         /**
1655          * DELETE where the condition is a join
1656          * @param $delTable String: deleting from this table
1657          * @param $joinTable String: using data from this table
1658          * @param $delVar String: variable in deleteable table
1659          * @param $joinVar String: variable in data table
1660          * @param $conds Array: conditionals for join table
1661          * @param $fname String: function name for profiling
1662          */
1663         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = "DatabaseIbm_db2::deleteJoin" ) {
1664                 if ( !$conds ) {
1665                         throw new DBUnexpectedError($this,  'Database::deleteJoin() called with empty $conds' );
1666                 }
1667
1668                 $delTable = $this->tableName( $delTable );
1669                 $joinTable = $this->tableName( $joinTable );
1670                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
1671                 if ( $conds != '*' ) {
1672                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1673                 }
1674                 $sql .= ')';
1675
1676                 $this->query( $sql, $fname );
1677         }
1678
1679         /**
1680          * Description is left as an exercise for the reader
1681          * @param $b Mixed: data to be encoded
1682          * @return IBM_DB2Blob
1683          */
1684         public function encodeBlob($b) {
1685                 return new IBM_DB2Blob($b);
1686         }
1687
1688         /**
1689          * Description is left as an exercise for the reader
1690          * @param $b IBM_DB2Blob: data to be decoded
1691          * @return mixed
1692          */
1693         public function decodeBlob($b) {
1694                 return $b->getData();
1695         }
1696
1697         /**
1698          * Convert into a list of string being concatenated
1699          * @param $stringList Array: strings that need to be joined together by the SQL engine
1700          * @return String: joined by the concatenation operator
1701          */
1702         public function buildConcat( $stringList ) {
1703                 // || is equivalent to CONCAT
1704                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1705                 return implode( ' || ', $stringList );
1706         }
1707
1708         /**
1709          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1710          * @param $column String: name of timestamp column
1711          * @return String: SQL code
1712          */
1713         public function extractUnixEpoch( $column ) {
1714                 // TODO
1715                 // see SpecialAncientpages
1716         }
1717
1718         ######################################
1719         # Prepared statements
1720         ######################################
1721
1722         /**
1723          * Intended to be compatible with the PEAR::DB wrapper functions.
1724          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1725          *
1726          * ? = scalar value, quoted as necessary
1727          * ! = raw SQL bit (a function for instance)
1728          * & = filename; reads the file and inserts as a blob
1729          *     (we don't use this though...)
1730          * @param $sql String: SQL statement with appropriate markers
1731          * @param $func String: Name of the function, for profiling
1732          * @return resource a prepared DB2 SQL statement
1733          */
1734         public function prepare( $sql, $func = 'DB2::prepare' ) {
1735                 $stmt = db2_prepare($this->mConn, $sql, $this->mStmtOptions);
1736                 return $stmt;
1737         }
1738
1739         /**
1740          * Frees resources associated with a prepared statement
1741          * @return Boolean success or failure
1742          */
1743         public function freePrepared( $prepared ) {
1744                 return db2_free_stmt($prepared);
1745         }
1746
1747         /**
1748          * Execute a prepared query with the various arguments
1749          * @param $prepared String: the prepared sql
1750          * @param $args Mixed: either an array here, or put scalars as varargs
1751          * @return Resource: results object
1752          */
1753         public function execute( $prepared, $args = null ) {
1754                 if( !is_array( $args ) ) {
1755                         # Pull the var args
1756                         $args = func_get_args();
1757                         array_shift( $args );
1758                 }
1759                 $res = db2_execute($prepared, $args);
1760                 return $res;
1761         }
1762
1763         /**
1764          * Prepare & execute an SQL statement, quoting and inserting arguments
1765          * in the appropriate places.
1766          * @param $query String
1767          * @param $args ...
1768          */
1769         public function safeQuery( $query, $args = null ) {
1770                 // copied verbatim from Database.php
1771                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1772                 if( !is_array( $args ) ) {
1773                         # Pull the var args
1774                         $args = func_get_args();
1775                         array_shift( $args );
1776                 }
1777                 $retval = $this->execute( $prepared, $args );
1778                 $this->freePrepared( $prepared );
1779                 return $retval;
1780         }
1781
1782         /**
1783          * For faking prepared SQL statements on DBs that don't support
1784          * it directly.
1785          * @param $preparedQuery String: a 'preparable' SQL statement
1786          * @param $args Array of arguments to fill it with
1787          * @return String: executable statement
1788          */
1789         public function fillPrepared( $preparedQuery, $args ) {
1790                 reset( $args );
1791                 $this->preparedArgs =& $args;
1792
1793                 foreach ($args as $i => $arg) {
1794                         db2_bind_param($preparedQuery, $i+1, $args[$i]);
1795                 }
1796
1797                 return $preparedQuery;
1798         }
1799
1800         /**
1801          * Switches module between regular and install modes
1802          */
1803         public function setMode($mode) {
1804                 $old =  $this->mMode;
1805                 $this->mMode = $mode;
1806                 return $old;
1807         }
1808
1809         /**
1810          * Bitwise negation of a column or value in SQL
1811          * Same as (~field) in C
1812          * @param $field String
1813          * @return String
1814          */
1815         function bitNot($field) {
1816                 //expecting bit-fields smaller than 4bytes
1817                 return 'BITNOT('.$bitField.')';
1818         }
1819
1820         /**
1821          * Bitwise AND of two columns or values in SQL
1822          * Same as (fieldLeft & fieldRight) in C
1823          * @param $fieldLeft String
1824          * @param $fieldRight String
1825          * @return String
1826          */
1827         function bitAnd($fieldLeft, $fieldRight) {
1828                 return 'BITAND('.$fieldLeft.', '.$fieldRight.')';
1829         }
1830
1831         /**
1832          * Bitwise OR of two columns or values in SQL
1833          * Same as (fieldLeft | fieldRight) in C
1834          * @param $fieldLeft String
1835          * @param $fieldRight String
1836          * @return String
1837          */
1838         function bitOr($fieldLeft, $fieldRight) {
1839                 return 'BITOR('.$fieldLeft.', '.$fieldRight.')';
1840         }
1841 }