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