includes/db/DatabaseIbm_db2.php

   1 <?php
   2 /**
   3  * This is the IBM DB2 database abstraction layer.
   4  * See maintenance/ibm_db2/README for development notes and other specific information
   5  *
   6  * @file
   7  * @ingroup Database
   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          * bufferResults
 169          * ignoreErrors
 170          * trxLevel
 171          * errorCount
 172          * getLBInfo
 173          * setLBInfo
 174          * lastQuery
 175          * isOpen
 176          * setFlag
 177          * clearFlag
 178          * getFlag
 179          * getProperty
 180          * getDBname
 181          * getServer
 182          * tableNameCallback
 183          * tablePrefix
 184          *
 185          * Administrative: (8)
 186          * debug
 187          * installErrorHandler
 188          * restoreErrorHandler
 189          * connectionErrorHandler
 190          * reportConnectionError
 191          * sourceFile
 192          * sourceStream
 193          * replaceVars
 194          *
 195          * Database: (5)
 196          * query
 197          * set
 198          * selectField
 199          * generalizeSQL
 200          * update
 201          * strreplace
 202          * deadlockLoop
 203          *
 204          * Prepared Statement: 6
 205          * prepare
 206          * freePrepared
 207          * execute
 208          * safeQuery
 209          * fillPrepared
 210          * fillPreparedArg
 211          *
 212          * Slave/Master: (4)
 213          * masterPosWait
 214          * getSlavePos
 215          * getMasterPos
 216          * getLag
 217          * setFakeMaster
 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] - Where??
 292          *
 293          * Reflection: 5 / 5
 294          * indexInfo [Done]
 295          * fieldInfo [Done]
 296          * fieldType [Done]
 297          * indexUnique [Done]
 298          * textFieldSize [Done]
 299          *
 300          * Generation: 16 / 16
 301          * tableName [Done]
 302          * addQuotes [Done]
 303          * makeList [Done]
 304          * makeSelectOptions [Done]
 305          * estimateRowCount [Done]
 306          * nextSequenceValue [Done]
 307          * useIndexClause [Done]
 308          * replace [Done]
 309          * deleteJoin [Done]
 310          * lowPriorityOption [Done]
 311          * limitResult [Done]
 312          * limitResultForUpdate [Done]
 313          * timestamp [Done]
 314          * encodeBlob [Done]
 315          * decodeBlob [Done]
 316          * buildConcat [Done]
 317          */
 318
 319         ######################################
 320         # Getters and Setters
 321         ######################################
 322
 323         /**
 324          * Returns true if this database supports (and uses) cascading deletes
 325          */
 326         function cascadingDeletes() {
 327                 return true;
 328         }
 329
 330         /**
 331          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 332          */
 333         function cleanupTriggers() {
 334                 return true;
 335         }
 336
 337         /**
 338          * Returns true if this database is strict about what can be put into an IP field.
 339          * Specifically, it uses a NULL value instead of an empty string.
 340          */
 341         function strictIPs() {
 342                 return true;
 343         }
 344
 345         /**
 346          * Returns true if this database uses timestamps rather than integers
 347         */
 348         function realTimestamps() {
 349                 return true;
 350         }
 351
 352         /**
 353          * Returns true if this database does an implicit sort when doing GROUP BY
 354          */
 355         function implicitGroupby() {
 356                 return false;
 357         }
 358
 359         /**
 360          * Returns true if this database does an implicit order by when the column has an index
 361          * For example: SELECT page_title FROM page LIMIT 1
 362          */
 363         function implicitOrderby() {
 364                 return false;
 365         }
 366
 367         /**
 368          * Returns true if this database can do a native search on IP columns
 369          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 370          */
 371         function searchableIPs() {
 372                 return true;
 373         }
 374
 375         /**
 376          * Returns true if this database can use functional indexes
 377          */
 378         function functionalIndexes() {
 379                 return true;
 380         }
 381
 382         /**
 383          * Returns a unique string representing the wiki on the server
 384          */
 385         function getWikiID() {
 386                 if( $this->mSchema ) {
 387                         return "{$this->mDBname}-{$this->mSchema}";
 388                 } else {
 389                         return $this->mDBname;
 390                 }
 391         }
 392
 393         function getType() {
 394                 return 'ibm_db2';
 395         }
 396
 397         ######################################
 398         # Setup
 399         ######################################
 400
 401
 402         /**
 403          *
 404          * @param $server String: hostname of database server
 405          * @param $user String: username
 406          * @param $password String: password
 407          * @param $dbName String: database name on the server
 408          * @param $failFunction Callback (optional)
 409          * @param $flags Integer: database behaviour flags (optional, unused)
 410          * @param $schema String
 411          */
 412         public function DatabaseIbm_db2($server = false, $user = false, $password = false,
 413                                                         $dbName = false, $failFunction = false, $flags = 0,
 414                                                         $schema = self::USE_GLOBAL )
 415         {
 416
 417                 global $wgOut, $wgDBmwschema;
 418                 # Can't get a reference if it hasn't been set yet
 419                 if ( !isset( $wgOut ) ) {
 420                         $wgOut = null;
 421                 }
 422                 $this->mOut =& $wgOut;
 423                 $this->mFailFunction = $failFunction;
 424                 $this->mFlags = DBO_TRX | $flags;
 425
 426                 if ( $schema == self::USE_GLOBAL ) {
 427                         $this->mSchema = $wgDBmwschema;
 428                 }
 429                 else {
 430                         $this->mSchema = $schema;
 431                 }
 432
 433                 // configure the connection and statement objects
 434                 $this->setDB2Option('db2_attr_case', 'DB2_CASE_LOWER', self::CONN_OPTION | self::STMT_OPTION);
 435                 $this->setDB2Option('deferred_prepare', 'DB2_DEFERRED_PREPARE_ON', self::STMT_OPTION);
 436                 $this->setDB2Option('rowcount', 'DB2_ROWCOUNT_PREFETCH_ON', self::STMT_OPTION);
 437
 438                 $this->open( $server, $user, $password, $dbName);
 439         }
 440
 441         /**
 442          * Enables options only if the ibm_db2 extension version supports them
 443          * @param $name String: name of the option in the options array
 444          * @param $const String: name of the constant holding the right option value
 445          * @param $type Integer: whether this is a Connection or Statement otion
 446          */
 447         private function setDB2Option($name, $const, $type) {
 448                 if (defined($const)) {
 449                         if ($type & self::CONN_OPTION) $this->mConnOptions[$name] = constant($const);
 450                         if ($type & self::STMT_OPTION) $this->mStmtOptions[$name] = constant($const);
 451                 }
 452                 else {
 453                         $this->installPrint("$const is not defined. ibm_db2 version is likely too low.");
 454                 }
 455         }
 456
 457         /**
 458          * Outputs debug information in the appropriate place
 459          * @param $string String: the relevant debug message
 460          */
 461         private function installPrint($string) {
 462                 wfDebug("$string\n");
 463                 if ($this->mMode == self::INSTALL_MODE) {
 464                         print "<li>$string</li>";
 465                         flush();
 466                 }
 467         }
 468
 469         /**
 470          * Opens a database connection and returns it
 471          * Closes any existing connection
 472          * @return a fresh connection
 473          * @param $server String: hostname
 474          * @param $user String
 475          * @param $password String
 476          * @param $dbName String: database name
 477          */
 478         public function open( $server, $user, $password, $dbName )
 479         {
 480                 // Load the port number
 481                 global $wgDBport, $wgDBcataloged;
 482                 wfProfileIn( __METHOD__ );
 483
 484                 // Load IBM DB2 driver if missing
 485                 wfDl( 'ibm_db2' );
 486
 487                 // Test for IBM DB2 support, to avoid suppressed fatal error
 488                 if ( !function_exists( 'db2_connect' ) ) {
 489                         $error = "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?\n";
 490                         $this->installPrint($error);
 491                         $this->reportConnectionError($error);
 492                 }
 493
 494                 if (!strlen($user)) { // Copied from Postgres
 495                         return null;
 496                 }
 497
 498                 // Close existing connection
 499                 $this->close();
 500                 // Cache conn info
 501                 $this->mServer = $server;
 502                 $this->mPort = $port = $wgDBport;
 503                 $this->mUser = $user;
 504                 $this->mPassword = $password;
 505                 $this->mDBname = $dbName;
 506                 $this->mCataloged = $cataloged = $wgDBcataloged;
 507
 508                 if ( $cataloged == self::CATALOGED ) {
 509                         $this->openCataloged($dbName, $user, $password);
 510                 }
 511                 elseif ( $cataloged == self::UNCATALOGED ) {
 512                         $this->openUncataloged($dbName, $user, $password, $server, $port);
 513                 }
 514                 // Apply connection config
 515                 db2_set_option($this->mConn, $this->mConnOptions, 1);
 516                 // Not all MediaWiki code is transactional
 517                 // Rather, turn autocommit off in the begin function and turn on after a commit
 518                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 519
 520                 if ( !$this->mConn ) {
 521                         $this->installPrint( "DB connection error\n" );
 522                         $this->installPrint( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 523                         $this->installPrint( $this->lastError()."\n" );
 524                         return null;
 525                 }
 526
 527                 $this->mOpened = true;
 528                 $this->applySchema();
 529
 530                 wfProfileOut( __METHOD__ );
 531                 return $this->mConn;
 532         }
 533
 534         /**
 535          * Opens a cataloged database connection, sets mConn
 536          */
 537         protected function openCataloged( $dbName, $user, $password )
 538         {
 539                 @$this->mConn = db2_connect($dbName, $user, $password);
 540         }
 541
 542         /**
 543          * Opens an uncataloged database connection, sets mConn
 544          */
 545         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 546         {
 547                 $str = "DRIVER={IBM DB2 ODBC DRIVER};";
 548                 $str .= "DATABASE=$dbName;";
 549                 $str .= "HOSTNAME=$server;";
 550                 if ($port) $str .= "PORT=$port;";
 551                 $str .= "PROTOCOL=TCPIP;";
 552                 $str .= "UID=$user;";
 553                 $str .= "PWD=$password;";
 554
 555                 @$this->mConn = db2_connect($str, $user, $password);
 556         }
 557
 558         /**
 559          * Closes a database connection, if it is open
 560          * Returns success, true if already closed
 561          */
 562         public function close() {
 563                 $this->mOpened = false;
 564                 if ( $this->mConn ) {
 565                         if ($this->trxLevel() > 0) {
 566                                 $this->commit();
 567                         }
 568                         return db2_close( $this->mConn );
 569                 }
 570                 else {
 571                         return true;
 572                 }
 573         }
 574
 575         /**
 576          * Returns a fresh instance of this class
 577          *
 578          * @param $server String: hostname of database server
 579          * @param $user String: username
 580          * @param $password String
 581          * @param $dbName String: database name on the server
 582          * @param $failFunction Callback (optional)
 583          * @param $flags Integer: database behaviour flags (optional, unused)
 584          * @return DatabaseIbm_db2 object
 585          */
 586         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0)
 587         {
 588                 return new DatabaseIbm_db2( $server, $user, $password, $dbName, $failFunction, $flags );
 589         }
 590
 591         /**
 592          * Retrieves the most current database error
 593          * Forces a database rollback
 594          */
 595         public function lastError() {
 596                 $connerr = db2_conn_errormsg();
 597                 if ($connerr) {
 598                         //$this->rollback();
 599                         return $connerr;
 600                 }
 601                 $stmterr = db2_stmt_errormsg();
 602                 if ($stmterr) {
 603                         //$this->rollback();
 604                         return $stmterr;
 605                 }
 606
 607                 return false;
 608         }
 609
 610         /**
 611          * Get the last error number
 612          * Return 0 if no error
 613          * @return integer
 614          */
 615         public function lastErrno() {
 616                 $connerr = db2_conn_error();
 617                 if ($connerr) return $connerr;
 618                 $stmterr = db2_stmt_error();
 619                 if ($stmterr) return $stmterr;
 620                 return 0;
 621         }
 622
 623         /**
 624          * Is a database connection open?
 625          * @return
 626          */
 627         public function isOpen() { return $this->mOpened; }
 628
 629         /**
 630          * The DBMS-dependent part of query()
 631          * @param  $sql String: SQL query.
 632          * @return object Result object to feed to fetchObject, fetchRow, ...; or false on failure
 633          * @access private
 634          */
 635         /*private*/
 636         public function doQuery( $sql ) {
 637                 $this->applySchema();
 638
 639                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 640                 if( $ret == FALSE ) {
 641                         $error = db2_stmt_errormsg();
 642                         $this->installPrint("<pre>$sql</pre>");
 643                         $this->installPrint($error);
 644                         throw new DBUnexpectedError($this,  'SQL error: ' . htmlspecialchars( $error ) );
 645                 }
 646                 $this->mLastResult = $ret;
 647                 $this->mAffectedRows = null;    // Not calculated until asked for
 648                 return $ret;
 649         }
 650
 651         /**
 652          * @return string Version information from the database
 653          */
 654         public function getServerVersion() {
 655                 $info = db2_server_info( $this->mConn );
 656                 return $info->DBMS_VER;
 657         }
 658
 659         /**
 660          * Queries whether a given table exists
 661          * @return boolean
 662          */
 663         public function tableExists( $table ) {
 664                 $schema = $this->mSchema;
 665                 $sql = <<< EOF
 666 SELECT COUNT(*) FROM SYSIBM.SYSTABLES ST
 667 WHERE ST.NAME = '$table' AND ST.CREATOR = '$schema'
 668 EOF;
 669                 $res = $this->query( $sql );
 670                 if (!$res) return false;
 671
 672                 // If the table exists, there should be one of it
 673                 @$row = $this->fetchRow($res);
 674                 $count = $row[0];
 675                 if ($count == '1' or $count == 1) {
 676                         return true;
 677                 }
 678
 679                 return false;
 680         }
 681
 682         /**
 683          * Fetch the next row from the given result object, in object form.
 684          * Fields can be retrieved with $row->fieldname, with fields acting like
 685          * member variables.
 686          *
 687          * @param $res SQL result object as returned from Database::query(), etc.
 688          * @return DB2 row object
 689          * @throws DBUnexpectedError Thrown if the database returns an error
 690          */
 691         public function fetchObject( $res ) {
 692                 if ( $res instanceof ResultWrapper ) {
 693                         $res = $res->result;
 694                 }
 695                 @$row = db2_fetch_object( $res );
 696                 if( $this->lastErrno() ) {
 697                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 698                 }
 699                 return $row;
 700         }
 701
 702         /**
 703          * Fetch the next row from the given result object, in associative array
 704          * form.  Fields are retrieved with $row['fieldname'].
 705          *
 706          * @param $res SQL result object as returned from Database::query(), etc.
 707          * @return DB2 row object
 708          * @throws DBUnexpectedError Thrown if the database returns an error
 709          */
 710         public function fetchRow( $res ) {
 711                 if ( $res instanceof ResultWrapper ) {
 712                         $res = $res->result;
 713                 }
 714                 @$row = db2_fetch_array( $res );
 715                 if ( $this->lastErrno() ) {
 716                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 717                 }
 718                 return $row;
 719         }
 720
 721         /**
 722          * Override if introduced to base Database class
 723          */
 724         public function initial_setup() {
 725                 // do nothing
 726         }
 727
 728         /**
 729          * Create tables, stored procedures, and so on
 730          */
 731         public function setup_database() {
 732                 // Timeout was being changed earlier due to mysterious crashes
 733                 // Changing it now may cause more problems than not changing it
 734                 //set_time_limit(240);
 735                 try {
 736                         // TODO: switch to root login if available
 737
 738                         // Switch into the correct namespace
 739                         $this->applySchema();
 740                         $this->begin();
 741
 742                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 743                         if ($res !== true) {
 744                                 print " <b>FAILED</b>: " . htmlspecialchars( $res ) . "</li>";
 745                         } else {
 746                                 print " done</li>";
 747                         }
 748                         $res = $this->sourceFile( "../maintenance/ibm_db2/foreignkeys.sql" );
 749                         if ($res !== true) {
 750                                 print " <b>FAILED</b>: " . htmlspecialchars( $res ) . "</li>";
 751                         } else {
 752                                 print "<li>Foreign keys done</li>";
 753                         }
 754                         $res = null;
 755
 756                         // TODO: populate interwiki links
 757
 758                         if ($this->lastError()) {
 759                                 print "<li>Errors encountered during table creation -- rolled back</li>\n";
 760                                 print "<li>Please install again</li>\n";
 761                                 $this->rollback();
 762                         }
 763                         else {
 764                                 $this->commit();
 765                         }
 766                 }
 767                 catch (MWException $mwe)
 768                 {
 769                         print "<br><pre>$mwe</pre><br>";
 770                 }
 771         }
 772
 773         /**
 774          * Escapes strings
 775          * Doesn't escape numbers
 776          * @param $s String: string to escape
 777          * @return escaped string
 778          */
 779         public function addQuotes( $s ) {
 780                 //$this->installPrint("DB2::addQuotes($s)\n");
 781                 if ( is_null( $s ) ) {
 782                         return "NULL";
 783                 } else if ($s instanceof Blob) {
 784                         return "'".$s->fetch($s)."'";
 785                 } else if ($s instanceof IBM_DB2Blob) {
 786                         return "'".$this->decodeBlob($s)."'";
 787                 }
 788                 $s = $this->strencode($s);
 789                 if ( is_numeric($s) ) {
 790                         return $s;
 791                 }
 792                 else {
 793                         return "'$s'";
 794                 }
 795         }
 796
 797         /**
 798          * Verifies that a DB2 column/field type is numeric
 799          * @return bool true if numeric
 800          * @param $type String: DB2 column type
 801          */
 802         public function is_numeric_type( $type ) {
 803                 switch (strtoupper($type)) {
 804                 case 'SMALLINT':
 805                 case 'INTEGER':
 806                 case 'INT':
 807                 case 'BIGINT':
 808                 case 'DECIMAL':
 809                 case 'REAL':
 810                 case 'DOUBLE':
 811                 case 'DECFLOAT':
 812                         return true;
 813                 }
 814                 return false;
 815         }
 816
 817         /**
 818          * Alias for addQuotes()
 819          * @param $s String: string to escape
 820          * @return escaped string
 821          */
 822         public function strencode( $s ) {
 823                 // Bloody useless function
 824                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 825                 //  But also necessary
 826                 $s = db2_escape_string($s);
 827                 // Wide characters are evil -- some of them look like '
 828                 $s = utf8_encode($s);
 829                 // Fix its stupidity
 830                 $from = array("\\\\",   "\\'",  '\\n',  '\\t',  '\\"',  '\\r');
 831                 $to =   array("\\",             "''",   "\n",   "\t",   '"',    "\r");
 832                 $s = str_replace($from, $to, $s); // DB2 expects '', not \' escaping
 833                 return $s;
 834         }
 835
 836         /**
 837          * Switch into the database schema
 838          */
 839         protected function applySchema() {
 840                 if ( !($this->mSchemaSet) ) {
 841                         $this->mSchemaSet = true;
 842                         $this->begin();
 843                         $this->doQuery("SET SCHEMA = $this->mSchema");
 844                         $this->commit();
 845                 }
 846         }
 847
 848         /**
 849          * Start a transaction (mandatory)
 850          */
 851         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 852                 // turn off auto-commit
 853                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_OFF);
 854                 $this->mTrxLevel = 1;
 855         }
 856
 857         /**
 858          * End a transaction
 859          * Must have a preceding begin()
 860          */
 861         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 862                 db2_commit($this->mConn);
 863                 // turn auto-commit back on
 864                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 865                 $this->mTrxLevel = 0;
 866         }
 867
 868         /**
 869          * Cancel a transaction
 870          */
 871         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 872                 db2_rollback($this->mConn);
 873                 // turn auto-commit back on
 874                 // not sure if this is appropriate
 875                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 876                 $this->mTrxLevel = 0;
 877         }
 878
 879         /**
 880          * Makes an encoded list of strings from an array
 881          * $mode:
 882          *        LIST_COMMA         - comma separated, no field names
 883          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
 884          *        LIST_OR            - ORed WHERE clause (without the WHERE)
 885          *        LIST_SET           - comma separated with field names, like a SET clause
 886          *        LIST_NAMES         - comma separated field names
 887          *        LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 888          */
 889         function makeList( $a, $mode = LIST_COMMA ) {
 890                 if ( !is_array( $a ) ) {
 891                         throw new DBUnexpectedError( $this, 'DatabaseBase::makeList called with incorrect parameters' );
 892                 }
 893
 894                 // if this is for a prepared UPDATE statement
 895                 // (this should be promoted to the parent class
 896                 //  once other databases use prepared statements)
 897                 if ($mode == LIST_SET_PREPARED) {
 898                         $first = true;
 899                         $list = '';
 900                         foreach ( $a as $field => $value ) {
 901                                 if (!$first) {
 902                                         $list .= ", $field = ?";
 903                                 }
 904                                 else {
 905                                         $list .= "( $field = ?";
 906                                   $first = false;
 907                                 }
 908                         }
 909                         $list .= ')';
 910
 911                         return $list;
 912                 }
 913
 914                 // otherwise, call the usual function
 915                 return parent::makeList( $a, $mode );
 916         }
 917
 918         /**
 919          * Construct a LIMIT query with optional offset
 920          * This is used for query pages
 921          * @param $sql string SQL query we will append the limit too
 922          * @param $limit integer the SQL limit
 923          * @param $offset integer the SQL offset (default false)
 924          */
 925         public function limitResult($sql, $limit, $offset=false) {
 926                 if( !is_numeric($limit) ) {
 927                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
 928                 }
 929                 if( $offset ) {
 930                         //$this->installPrint("Offset parameter not supported in limitResult()\n");
 931                         if ( stripos($sql, 'where') === false ) {
 932                                 return "$sql AND (ROWNUM BETWEEN $offset AND $offset+$limit)";
 933                         }
 934                         else {
 935                                 return "$sql WHERE (ROWNUM BETWEEN $offset AND $offset+$limit)";
 936                         }
 937                 }
 938                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 939         }
 940
 941         /**
 942          * Handle reserved keyword replacement in table names
 943          * @return
 944          * @param $name Object
 945          */
 946         public function tableName( $name ) {
 947                 # Replace reserved words with better ones
 948 //              switch( $name ) {
 949 //                      case 'user':
 950 //                              return 'mwuser';
 951 //                      case 'text':
 952 //                              return 'pagecontent';
 953 //                      default:
 954 //                              return $name;
 955 //              }
 956                 // we want maximum compatibility with MySQL schema
 957                 return $name;
 958         }
 959
 960         /**
 961          * Generates a timestamp in an insertable format
 962          * @return string timestamp value
 963          * @param $ts timestamp
 964          */
 965         public function timestamp( $ts=0 ) {
 966                 // TS_MW cannot be easily distinguished from an integer
 967                 return wfTimestamp(TS_DB2,$ts);
 968         }
 969
 970         /**
 971          * Return the next in a sequence, save the value for retrieval via insertId()
 972          * @param $seqName String: name of a defined sequence in the database
 973          * @return next value in that sequence
 974          */
 975         public function nextSequenceValue( $seqName ) {
 976                 // Not using sequences in the primary schema to allow for easy third-party migration scripts
 977                 // Emulating MySQL behaviour of using NULL to signal that sequences aren't used
 978                 /*
 979                 $safeseq = preg_replace( "/'/", "''", $seqName );
 980                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 981                 $row = $this->fetchRow( $res );
 982                 $this->mInsertId = $row[0];
 983                 return $this->mInsertId;
 984                 */
 985                 return null;
 986         }
 987
 988         /**
 989          * This must be called after nextSequenceVal
 990          * @return Last sequence value used as a primary key
 991          */
 992         public function insertId() {
 993                 return $this->mInsertId;
 994         }
 995
 996         /**
 997          * Updates the mInsertId property with the value of the last insert into a generated column
 998          * @param $table      String: sanitized table name
 999          * @param $primaryKey Mixed: string name of the primary key or a bool if this call is a do-nothing
1000          * @param $stmt       Resource: prepared statement resource
1001          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
1002          */
1003         private function calcInsertId($table, $primaryKey, $stmt) {
1004                 if ($primaryKey) {
1005                         $this->mInsertId = db2_last_insert_id($this->mConn);
1006                         //$this->installPrint("Last $primaryKey for $table was $this->mInsertId");
1007                 }
1008         }
1009
1010         /**
1011          * INSERT wrapper, inserts an array into a table
1012          *
1013          * $args may be a single associative array, or an array of these with numeric keys,
1014          * for multi-row insert
1015          *
1016          * @param $table   String: Name of the table to insert to.
1017          * @param $args    Array: Items to insert into the table.
1018          * @param $fname   String: Name of the function, for profiling
1019          * @param $options String or Array. Valid options: IGNORE
1020          *
1021          * @return bool Success of insert operation. IGNORE always returns true.
1022          */
1023         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert', $options = array() ) {
1024                 if ( !count( $args ) ) {
1025                         return true;
1026                 }
1027                 // get database-specific table name (not used)
1028                 $table = $this->tableName( $table );
1029                 // format options as an array
1030                 $options = IBM_DB2Helper::makeArray($options);
1031                 // format args as an array of arrays
1032                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
1033                         $args = array($args);
1034                 }
1035
1036                 // prevent insertion of NULL into primary key columns
1037                 list($args, $primaryKeys) = $this->removeNullPrimaryKeys($table, $args);
1038                 // if there's only one primary key
1039                 // we'll be able to read its value after insertion
1040                 $primaryKey = false;
1041                 if (count($primaryKeys) == 1) {
1042                         $primaryKey = $primaryKeys[0];
1043                 }
1044
1045                 // get column names
1046                 $keys = array_keys( $args[0] );
1047                 $key_count = count($keys);
1048
1049                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
1050                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
1051
1052                 // assume success
1053                 $res = true;
1054                 // If we are not in a transaction, we need to be for savepoint trickery
1055                 if (! $this->mTrxLevel) {
1056                         $this->begin();
1057                 }
1058
1059                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1060                 if ($key_count == 1) {
1061                         $sql .= '(?)';
1062                 } else {
1063                         $sql .= '(?' . str_repeat(',?', $key_count-1) . ')';
1064                 }
1065                 //$this->installPrint("Preparing the following SQL:");
1066                 //$this->installPrint("$sql");
1067                 //$this->installPrint(print_r($args, true));
1068                 $stmt = $this->prepare($sql);
1069
1070                 // start a transaction/enter transaction mode
1071                 $this->begin();
1072
1073                 if ( !$ignore ) {
1074                         //$first = true;
1075                         foreach ( $args as $row ) {
1076                                 //$this->installPrint("Inserting " . print_r($row, true));
1077                                 // insert each row into the database
1078                                 $res = $res & $this->execute($stmt, $row);
1079                                 if (!$res) {
1080                                         $this->installPrint("Last error:");
1081                                         $this->installPrint($this->lastError());
1082                                 }
1083                                 // get the last inserted value into a generated column
1084                                 $this->calcInsertId($table, $primaryKey, $stmt);
1085                         }
1086                 }
1087                 else {
1088                         $olde = error_reporting( 0 );
1089                         // For future use, we may want to track the number of actual inserts
1090                         // Right now, insert (all writes) simply return true/false
1091                         $numrowsinserted = 0;
1092
1093                         // always return true
1094                         $res = true;
1095
1096                         foreach ( $args as $row ) {
1097                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
1098                                 db2_exec($this->mConn, $overhead, $this->mStmtOptions);
1099                                 //$this->installPrint("Inserting " . print_r($row, true));
1100
1101                                 $this->execute($stmt, $row);
1102                                 //$this->installPrint(wfGetAllCallers());
1103                                 if (!$res2) {
1104                                         $this->installPrint("Last error:");
1105                                         $this->installPrint($this->lastError());
1106                                 }
1107                                 // get the last inserted value into a generated column
1108                                 $this->calcInsertId($table, $primaryKey, $stmt);
1109
1110                                 $errNum = $this->lastErrno();
1111                                 if ($errNum) {
1112                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore", $this->mStmtOptions );
1113                                 }
1114                                 else {
1115                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore", $this->mStmtOptions );
1116                                         $numrowsinserted++;
1117                                 }
1118                         }
1119
1120                         $olde = error_reporting( $olde );
1121                         // Set the affected row count for the whole operation
1122                         $this->mAffectedRows = $numrowsinserted;
1123                 }
1124                 // commit either way
1125                 $this->commit();
1126                 $this->freePrepared($stmt);
1127
1128                 return $res;
1129         }
1130
1131         /**
1132          * Given a table name and a hash of columns with values
1133          * Removes primary key columns from the hash where the value is NULL
1134          *
1135          * @param $table String: name of the table
1136          * @param $args Array of hashes of column names with values
1137          * @return Array: tuple containing filtered array of columns, array of primary keys
1138          */
1139         private function removeNullPrimaryKeys($table, $args) {
1140                 $schema = $this->mSchema;
1141                 // find out the primary keys
1142                 $keyres = db2_primary_keys($this->mConn, null, strtoupper($schema), strtoupper($table));
1143                 $keys = array();
1144                 for ($row = $this->fetchObject($keyres); $row != null; $row = $this->fetchRow($keyres)) {
1145                         $keys[] = strtolower($row->column_name);
1146                 }
1147                 // remove primary keys
1148                 foreach ($args as $ai => $row) {
1149                         foreach ($keys as $ki => $key) {
1150                                 if ($row[$key] == null) {
1151                                         unset($row[$key]);
1152                                 }
1153                         }
1154                         $args[$ai] = $row;
1155                 }
1156                 // return modified hash
1157                 return array($args, $keys);
1158         }
1159
1160         /**
1161          * UPDATE wrapper, takes a condition array and a SET array
1162          *
1163          * @param $table  String: The table to UPDATE
1164          * @param $values An array of values to SET
1165          * @param $conds  An array of conditions (WHERE). Use '*' to update all rows.
1166          * @param $fname  String: The Class::Function calling this function
1167          *                (for the log)
1168          * @param $options An array of UPDATE options, can be one or
1169          *                 more of IGNORE, LOW_PRIORITY
1170          * @return Boolean
1171          */
1172         public function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1173                 $table = $this->tableName( $table );
1174                 $opts = $this->makeUpdateOptions( $options );
1175                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET_PREPARED );
1176                 if ( $conds != '*' ) {
1177                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1178                 }
1179                 $stmt = $this->prepare( $sql );
1180                 $this->installPrint("UPDATE: " . print_r($values, TRUE));
1181                 // assuming for now that an array with string keys will work
1182                 // if not, convert to simple array first
1183                 $result = $this->execute( $stmt, $values );
1184                 $this->freePrepared( $stmt );
1185                 //$result = $this->query( $sql, $fname );
1186                 // commit regardless of state
1187                 //$this->commit();
1188                 return $result;
1189         }
1190
1191         /**
1192          * DELETE query wrapper
1193          *
1194          * Use $conds == "*" to delete all rows
1195          */
1196         public function delete( $table, $conds, $fname = 'Database::delete' ) {
1197                 if ( !$conds ) {
1198                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1199                 }
1200                 $table = $this->tableName( $table );
1201                 $sql = "DELETE FROM $table";
1202                 if ( $conds != '*' ) {
1203                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1204                 }
1205                 $result = $this->query( $sql, $fname );
1206                 // commit regardless
1207                 //$this->commit();
1208                 return $result;
1209         }
1210
1211         /**
1212          * Returns the number of rows affected by the last query or 0
1213          * @return Integer: the number of rows affected by the last query
1214          */
1215         public function affectedRows() {
1216                 if ( !is_null( $this->mAffectedRows ) ) {
1217                         // Forced result for simulated queries
1218                         return $this->mAffectedRows;
1219                 }
1220                 if( empty( $this->mLastResult ) )
1221                         return 0;
1222                 return db2_num_rows( $this->mLastResult );
1223         }
1224
1225         /**
1226          * Simulates REPLACE with a DELETE followed by INSERT
1227          * @param $table Object
1228          * @param $uniqueIndexes Array consisting of indexes and arrays of indexes
1229          * @param $rows Array: rows to insert
1230          * @param $fname String: name of the function for profiling
1231          * @return nothing
1232          */
1233         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseIbm_db2::replace' ) {
1234                 $table = $this->tableName( $table );
1235
1236                 if (count($rows)==0) {
1237                         return;
1238                 }
1239
1240                 # Single row case
1241                 if ( !is_array( reset( $rows ) ) ) {
1242                         $rows = array( $rows );
1243                 }
1244
1245                 foreach( $rows as $row ) {
1246                         # Delete rows which collide
1247                         if ( $uniqueIndexes ) {
1248                                 $sql = "DELETE FROM $table WHERE ";
1249                                 $first = true;
1250                                 foreach ( $uniqueIndexes as $index ) {
1251                                         if ( $first ) {
1252                                                 $first = false;
1253                                                 $sql .= "(";
1254                                         } else {
1255                                                 $sql .= ') OR (';
1256                                         }
1257                                         if ( is_array( $index ) ) {
1258                                                 $first2 = true;
1259                                                 foreach ( $index as $col ) {
1260                                                         if ( $first2 ) {
1261                                                                 $first2 = false;
1262                                                         } else {
1263                                                                 $sql .= ' AND ';
1264                                                         }
1265                                                         $sql .= $col.'=' . $this->addQuotes( $row[$col] );
1266                                                 }
1267                                         } else {
1268                                                 $sql .= $index.'=' . $this->addQuotes( $row[$index] );
1269                                         }
1270                                 }
1271                                 $sql .= ')';
1272                                 $this->query( $sql, $fname );
1273                         }
1274
1275                         # Now insert the row
1276                         $sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
1277                                 $this->makeList( $row, LIST_COMMA ) . ')';
1278                         $this->query( $sql, $fname );
1279                 }
1280         }
1281
1282         /**
1283          * Returns the number of rows in the result set
1284          * Has to be called right after the corresponding select query
1285          * @param $res Object result set
1286          * @return Integer: number of rows
1287          */
1288         public function numRows( $res ) {
1289                 if ( $res instanceof ResultWrapper ) {
1290                         $res = $res->result;
1291                 }
1292                 if ( $this->mNumRows ) {
1293                         return $this->mNumRows;
1294                 }
1295                 else {
1296                         return 0;
1297                 }
1298         }
1299
1300         /**
1301          * Moves the row pointer of the result set
1302          * @param $res Object: result set
1303          * @param $row Integer: row number
1304          * @return success or failure
1305          */
1306         public function dataSeek( $res, $row ) {
1307                 if ( $res instanceof ResultWrapper ) {
1308                         $res = $res->result;
1309                 }
1310                 return db2_fetch_row( $res, $row );
1311         }
1312
1313         ###
1314         # Fix notices in Block.php
1315         ###
1316
1317         /**
1318          * Frees memory associated with a statement resource
1319          * @param $res Object: statement resource to free
1320          * @return Boolean success or failure
1321          */
1322         public function freeResult( $res ) {
1323                 if ( $res instanceof ResultWrapper ) {
1324                         $res = $res->result;
1325                 }
1326                 if ( !@db2_free_result( $res ) ) {
1327                         throw new DBUnexpectedError($this,  "Unable to free DB2 result\n" );
1328                 }
1329         }
1330
1331         /**
1332          * Returns the number of columns in a resource
1333          * @param $res Object: statement resource
1334          * @return Number of fields/columns in resource
1335          */
1336         public function numFields( $res ) {
1337                 if ( $res instanceof ResultWrapper ) {
1338                         $res = $res->result;
1339                 }
1340                 return db2_num_fields( $res );
1341         }
1342
1343         /**
1344          * Returns the nth column name
1345          * @param $res Object: statement resource
1346          * @param $n Integer: Index of field or column
1347          * @return String name of nth column
1348          */
1349         public function fieldName( $res, $n ) {
1350                 if ( $res instanceof ResultWrapper ) {
1351                         $res = $res->result;
1352                 }
1353                 return db2_field_name( $res, $n );
1354         }
1355
1356         /**
1357          * SELECT wrapper
1358          *
1359          * @param $table   Array or string, table name(s) (prefix auto-added)
1360          * @param $vars    Array or string, field name(s) to be retrieved
1361          * @param $conds   Array or string, condition(s) for WHERE
1362          * @param $fname   String: calling function name (use __METHOD__) for logs/profiling
1363          * @param $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1364          *                 see Database::makeSelectOptions code for list of supported stuff
1365          * @param $join_conds Associative array of table join conditions (optional)
1366          *                    (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
1367          * @return Mixed: database result resource (feed to Database::fetchObject or whatever), or false on failure
1368          */
1369         public function select( $table, $vars, $conds='', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1370         {
1371                 $res = parent::select( $table, $vars, $conds, $fname, $options, $join_conds );
1372
1373                 // We must adjust for offset
1374                 if ( isset( $options['LIMIT'] ) ) {
1375                         if ( isset ($options['OFFSET'] ) ) {
1376                                 $limit = $options['LIMIT'];
1377                                 $offset = $options['OFFSET'];
1378                         }
1379                 }
1380
1381
1382                 // DB2 does not have a proper num_rows() function yet, so we must emulate it
1383                 // DB2 9.5.3/9.5.4 and the corresponding ibm_db2 driver will introduce a working one
1384                 // Yay!
1385
1386                 // we want the count
1387                 $vars2 = array('count(*) as num_rows');
1388                 // respecting just the limit option
1389                 $options2 = array();
1390                 if ( isset( $options['LIMIT'] ) ) $options2['LIMIT'] = $options['LIMIT'];
1391                 // but don't try to emulate for GROUP BY
1392                 if ( isset( $options['GROUP BY'] ) ) return $res;
1393
1394                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2, $join_conds );
1395                 $obj = $this->fetchObject($res2);
1396                 $this->mNumRows = $obj->num_rows;
1397
1398
1399                 return $res;
1400         }
1401
1402         /**
1403          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1404          * Has limited support for per-column options (colnum => 'DISTINCT')
1405          *
1406          * @private
1407          *
1408          * @param $options Associative array of options to be turned into
1409          *              an SQL query, valid keys are listed in the function.
1410          * @return Array
1411          */
1412         function makeSelectOptions( $options ) {
1413                 $preLimitTail = $postLimitTail = '';
1414                 $startOpts = '';
1415
1416                 $noKeyOptions = array();
1417                 foreach ( $options as $key => $option ) {
1418                         if ( is_numeric( $key ) ) {
1419                                 $noKeyOptions[$option] = true;
1420                         }
1421                 }
1422
1423                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1424                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
1425                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1426
1427                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
1428
1429                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1430         }
1431
1432         /**
1433          * Returns link to IBM DB2 free download
1434          * @return string wikitext of a link to the server software's web site
1435          */
1436         public static function getSoftwareLink() {
1437                 return "[http://www.ibm.com/software/data/db2/express/?s_cmp=ECDDWW01&s_tact=MediaWiki IBM DB2]";
1438         }
1439
1440         /**
1441          * Get search engine class. All subclasses of this
1442          * need to implement this if they wish to use searching.
1443          *
1444          * @return String
1445          */
1446         public function getSearchEngine() {
1447                 return "SearchIBM_DB2";
1448         }
1449
1450         /**
1451          * Did the last database access fail because of deadlock?
1452          * @return Boolean
1453          */
1454         public function wasDeadlock() {
1455                 // get SQLSTATE
1456                 $err = $this->lastErrno();
1457                 switch($err) {
1458                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1459                         case '57011':   // sql0904n, Resource unavailable, no rollback
1460                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1461                         $this->installPrint("In a deadlock because of SQLSTATE $err");
1462                         return true;
1463                 }
1464                 return false;
1465         }
1466
1467         /**
1468          * Ping the server and try to reconnect if it there is no connection
1469          * The connection may be closed and reopened while this happens
1470          * @return Boolean: whether the connection exists
1471          */
1472         public function ping() {
1473                 // db2_ping() doesn't exist
1474                 // Emulate
1475                 $this->close();
1476                 if ($this->mCataloged == null) {
1477                         return false;
1478                 }
1479                 else if ($this->mCataloged) {
1480                         $this->mConn = $this->openCataloged($this->mDBName, $this->mUser, $this->mPassword);
1481                 }
1482                 else if (!$this->mCataloged) {
1483                         $this->mConn = $this->openUncataloged($this->mDBName, $this->mUser, $this->mPassword, $this->mServer, $this->mPort);
1484                 }
1485                 return false;
1486         }
1487         ######################################
1488         # Unimplemented and not applicable
1489         ######################################
1490         /**
1491          * Not implemented
1492          * @return string ''
1493          */
1494         public function getStatus( $which="%" ) { $this->installPrint('Not implemented for DB2: getStatus()'); return ''; }
1495         /**
1496          * Not implemented
1497          * @return string $sql
1498          */
1499         public function limitResultForUpdate($sql, $num) { $this->installPrint('Not implemented for DB2: limitResultForUpdate()'); return $sql; }
1500
1501         /**
1502          * Only useful with fake prepare like in base Database class
1503          * @return      string
1504          */
1505         public function fillPreparedArg( $matches ) { $this->installPrint('Not useful for DB2: fillPreparedArg()'); return ''; }
1506
1507         ######################################
1508         # Reflection
1509         ######################################
1510
1511         /**
1512          * Returns information about an index
1513          * If errors are explicitly ignored, returns NULL on failure
1514          * @param $table String: table name
1515          * @param $index String: index name
1516          * @param $fname String: function name for logging and profiling
1517          * @return Object query row in object form
1518          */
1519         public function indexInfo( $table, $index, $fname = 'DatabaseIbm_db2::indexExists' ) {
1520                 $table = $this->tableName( $table );
1521                 $sql = <<<SQL
1522 SELECT name as indexname
1523 FROM sysibm.sysindexes si
1524 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1525 SQL;
1526                 $res = $this->query( $sql, $fname );
1527                 if ( !$res ) {
1528                         return null;
1529                 }
1530                 $row = $this->fetchObject( $res );
1531                 if ($row != null) return $row;
1532                 else return false;
1533         }
1534
1535         /**
1536          * Returns an information object on a table column
1537          * @param $table String: table name
1538          * @param $field String: column name
1539          * @return IBM_DB2Field
1540          */
1541         public function fieldInfo( $table, $field ) {
1542                 return IBM_DB2Field::fromText($this, $table, $field);
1543         }
1544
1545         /**
1546          * db2_field_type() wrapper
1547          * @param $res Object: result of executed statement
1548          * @param $index Mixed: number or name of the column
1549          * @return String column type
1550          */
1551         public function fieldType( $res, $index ) {
1552                 if ( $res instanceof ResultWrapper ) {
1553                         $res = $res->result;
1554                 }
1555                 return db2_field_type( $res, $index );
1556         }
1557
1558         /**
1559          * Verifies that an index was created as unique
1560          * @param $table String: table name
1561          * @param $index String: index name
1562          * @param $fname function name for profiling
1563          * @return Bool
1564          */
1565         public function indexUnique ($table, $index, $fname = 'Database::indexUnique' ) {
1566                 $table = $this->tableName( $table );
1567                 $sql = <<<SQL
1568 SELECT si.name as indexname
1569 FROM sysibm.sysindexes si
1570 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1571 AND si.uniquerule IN ('U', 'P')
1572 SQL;
1573                 $res = $this->query( $sql, $fname );
1574                 if ( !$res ) {
1575                         return null;
1576                 }
1577                 if ($this->fetchObject( $res )) {
1578                         return true;
1579                 }
1580                 return false;
1581
1582         }
1583
1584         /**
1585          * Returns the size of a text field, or -1 for "unlimited"
1586          * @param $table String: table name
1587          * @param $field String: column name
1588          * @return Integer: length or -1 for unlimited
1589          */
1590         public function textFieldSize( $table, $field ) {
1591                 $table = $this->tableName( $table );
1592                 $sql = <<<SQL
1593 SELECT length as size
1594 FROM sysibm.syscolumns sc
1595 WHERE sc.name='$field' AND sc.tbname='$table' AND sc.tbcreator='$this->mSchema'
1596 SQL;
1597                 $res = $this->query($sql);
1598                 $row = $this->fetchObject($res);
1599                 $size = $row->size;
1600                 return $size;
1601         }
1602
1603         /**
1604          * DELETE where the condition is a join
1605          * @param $delTable String: deleting from this table
1606          * @param $joinTable String: using data from this table
1607          * @param $delVar String: variable in deleteable table
1608          * @param $joinVar String: variable in data table
1609          * @param $conds Array: conditionals for join table
1610          * @param $fname String: function name for profiling
1611          */
1612         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = "DatabaseIbm_db2::deleteJoin" ) {
1613                 if ( !$conds ) {
1614                         throw new DBUnexpectedError($this,  'Database::deleteJoin() called with empty $conds' );
1615                 }
1616
1617                 $delTable = $this->tableName( $delTable );
1618                 $joinTable = $this->tableName( $joinTable );
1619                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
1620                 if ( $conds != '*' ) {
1621                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1622                 }
1623                 $sql .= ')';
1624
1625                 $this->query( $sql, $fname );
1626         }
1627
1628         /**
1629          * Description is left as an exercise for the reader
1630          * @param $b Mixed: data to be encoded
1631          * @return IBM_DB2Blob
1632          */
1633         public function encodeBlob($b) {
1634                 return new IBM_DB2Blob($b);
1635         }
1636
1637         /**
1638          * Description is left as an exercise for the reader
1639          * @param $b IBM_DB2Blob: data to be decoded
1640          * @return mixed
1641          */
1642         public function decodeBlob($b) {
1643                 return "$b";
1644         }
1645
1646         /**
1647          * Convert into a list of string being concatenated
1648          * @param $stringList Array: strings that need to be joined together by the SQL engine
1649          * @return String: joined by the concatenation operator
1650          */
1651         public function buildConcat( $stringList ) {
1652                 // || is equivalent to CONCAT
1653                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1654                 return implode( ' || ', $stringList );
1655         }
1656
1657         /**
1658          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1659          * @param $column String: name of timestamp column
1660          * @return String: SQL code
1661          */
1662         public function extractUnixEpoch( $column ) {
1663                 // TODO
1664                 // see SpecialAncientpages
1665         }
1666
1667         ######################################
1668         # Prepared statements
1669         ######################################
1670
1671         /**
1672          * Intended to be compatible with the PEAR::DB wrapper functions.
1673          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1674          *
1675          * ? = scalar value, quoted as necessary
1676          * ! = raw SQL bit (a function for instance)
1677          * & = filename; reads the file and inserts as a blob
1678          *     (we don't use this though...)
1679          * @param $sql String: SQL statement with appropriate markers
1680          * @param $func String: Name of the function, for profiling
1681          * @return resource a prepared DB2 SQL statement
1682          */
1683         public function prepare( $sql, $func = 'DB2::prepare' ) {
1684                 $stmt = db2_prepare($this->mConn, $sql, $this->mStmtOptions);
1685                 return $stmt;
1686         }
1687
1688         /**
1689          * Frees resources associated with a prepared statement
1690          * @return Boolean success or failure
1691          */
1692         public function freePrepared( $prepared ) {
1693                 return db2_free_stmt($prepared);
1694         }
1695
1696         /**
1697          * Execute a prepared query with the various arguments
1698          * @param $prepared String: the prepared sql
1699          * @param $args Mixed: either an array here, or put scalars as varargs
1700          * @return Resource: results object
1701          */
1702         public function execute( $prepared, $args = null ) {
1703                 if( !is_array( $args ) ) {
1704                         # Pull the var args
1705                         $args = func_get_args();
1706                         array_shift( $args );
1707                 }
1708                 $res = db2_execute($prepared, $args);
1709                 return $res;
1710         }
1711
1712         /**
1713          * Prepare & execute an SQL statement, quoting and inserting arguments
1714          * in the appropriate places.
1715          * @param $query String
1716          * @param $args ...
1717          */
1718         public function safeQuery( $query, $args = null ) {
1719                 // copied verbatim from Database.php
1720                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1721                 if( !is_array( $args ) ) {
1722                         # Pull the var args
1723                         $args = func_get_args();
1724                         array_shift( $args );
1725                 }
1726                 $retval = $this->execute( $prepared, $args );
1727                 $this->freePrepared( $prepared );
1728                 return $retval;
1729         }
1730
1731         /**
1732          * For faking prepared SQL statements on DBs that don't support
1733          * it directly.
1734          * @param $preparedQuery String: a 'preparable' SQL statement
1735          * @param $args Array of arguments to fill it with
1736          * @return String: executable statement
1737          */
1738         public function fillPrepared( $preparedQuery, $args ) {
1739                 reset( $args );
1740                 $this->preparedArgs =& $args;
1741
1742                 foreach ($args as $i => $arg) {
1743                         db2_bind_param($preparedQuery, $i+1, $args[$i]);
1744                 }
1745
1746                 return $preparedQuery;
1747         }
1748
1749         /**
1750          * Switches module between regular and install modes
1751          */
1752         public function setMode($mode) {
1753                 $old =  $this->mMode;
1754                 $this->mMode = $mode;
1755                 return $old;
1756         }
1757
1758         /**
1759          * Bitwise negation of a column or value in SQL
1760          * Same as (~field) in C
1761          * @param $field String
1762          * @return String
1763          */
1764         function bitNot($field) {
1765                 //expecting bit-fields smaller than 4bytes
1766                 return 'BITNOT('.$field.')';
1767         }
1768
1769         /**
1770          * Bitwise AND of two columns or values in SQL
1771          * Same as (fieldLeft & fieldRight) in C
1772          * @param $fieldLeft String
1773          * @param $fieldRight String
1774          * @return String
1775          */
1776         function bitAnd($fieldLeft, $fieldRight) {
1777                 return 'BITAND('.$fieldLeft.', '.$fieldRight.')';
1778         }
1779
1780         /**
1781          * Bitwise OR of two columns or values in SQL
1782          * Same as (fieldLeft | fieldRight) in C
1783          * @param $fieldLeft String
1784          * @param $fieldRight String
1785          * @return String
1786          */
1787         function bitOr($fieldLeft, $fieldRight) {
1788                 return 'BITOR('.$fieldLeft.', '.$fieldRight.')';
1789         }
1790 }
1791
1792 class IBM_DB2Helper {
1793         public static function makeArray($maybeArray) {
1794                 if ( !is_array( $maybeArray ) ) $maybeArray = array( $maybeArray );
1795
1796                 return $maybeArray;
1797         }
1798 }