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