includes/db/DatabaseIbm_db2.php

   1 <?php
   2 /**
   3  * This script is the IBM DB2 database abstraction layer
   4  *
   5  * See maintenance/ibm_db2/README for development notes and other specific information
   6  * @ingroup Database
   7  * @file
   8  * @author leo.petr+mediawiki@gmail.com
   9  */
  10
  11 /**
  12  * This represents a column in a DB2 database
  13  * @ingroup Database
  14  */
  15 class IBM_DB2Field {
  16         private $name = '';
  17         private $tablename = '';
  18         private $type = '';
  19         private $nullable = false;
  20         private $max_length = 0;
  21
  22         /**
  23          * Builder method for the class
  24          * @param DatabaseIbm_db2 $db Database interface
  25          * @param string $table table name
  26          * @param string $field column name
  27          * @return IBM_DB2Field
  28          */
  29         static function fromText($db, $table, $field) {
  30                 global $wgDBmwschema;
  31
  32                 $q = <<<SQL
  33 SELECT
  34 lcase(coltype) AS typname,
  35 nulls AS attnotnull, length AS attlen
  36 FROM sysibm.syscolumns
  37 WHERE tbcreator=%s AND tbname=%s AND name=%s;
  38 SQL;
  39                 $res = $db->query(sprintf($q,
  40                                 $db->addQuotes($wgDBmwschema),
  41                                 $db->addQuotes($table),
  42                                 $db->addQuotes($field)));
  43                 $row = $db->fetchObject($res);
  44                 if (!$row)
  45                         return null;
  46                 $n = new IBM_DB2Field;
  47                 $n->type = $row->typname;
  48                 $n->nullable = ($row->attnotnull == 'N');
  49                 $n->name = $field;
  50                 $n->tablename = $table;
  51                 $n->max_length = $row->attlen;
  52                 return $n;
  53         }
  54         /**
  55          * Get column name
  56          * @return string column name
  57          */
  58         function name() { return $this->name; }
  59         /**
  60          * Get table name
  61          * @return string table name
  62          */
  63         function tableName() { return $this->tablename; }
  64         /**
  65          * Get column type
  66          * @return string column type
  67          */
  68         function type() { return $this->type; }
  69         /**
  70          * Can column be null?
  71          * @return bool true or false
  72          */
  73         function nullable() { return $this->nullable; }
  74         /**
  75          * How much can you fit in the column per row?
  76          * @return int length
  77          */
  78         function maxLength() { return $this->max_length; }
  79 }
  80
  81 /**
  82  * Wrapper around binary large objects
  83  * @ingroup Database
  84  */
  85 class IBM_DB2Blob {
  86         private $mData;
  87
  88         public function __construct($data) {
  89                 $this->mData = $data;
  90         }
  91
  92         public function getData() {
  93                 return $this->mData;
  94         }
  95
  96         public function __toString()
  97     {
  98         return $this->mData;
  99     }
 100 }
 101
 102 /**
 103  * Primary database interface
 104  * @ingroup Database
 105  */
 106 class DatabaseIbm_db2 extends DatabaseBase {
 107         /*
 108          * Inherited members
 109         protected $mLastQuery = '';
 110         protected $mPHPError = false;
 111
 112         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 113         protected $mOut, $mOpened = false;
 114
 115         protected $mFailFunction;
 116         protected $mTablePrefix;
 117         protected $mFlags;
 118         protected $mTrxLevel = 0;
 119         protected $mErrorCount = 0;
 120         protected $mLBInfo = array();
 121         protected $mFakeSlaveLag = null, $mFakeMaster = false;
 122          *
 123          */
 124
 125         /// Server port for uncataloged connections
 126         protected $mPort = null;
 127         /// Whether connection is cataloged
 128         protected $mCataloged = null;
 129         /// Schema for tables, stored procedures, triggers
 130         protected $mSchema = null;
 131         /// Whether the schema has been applied in this session
 132         protected $mSchemaSet = false;
 133         /// Result of last query
 134         protected $mLastResult = null;
 135         /// Number of rows affected by last INSERT/UPDATE/DELETE
 136         protected $mAffectedRows = null;
 137         /// Number of rows returned by last SELECT
 138         protected $mNumRows = null;
 139
 140         /// Connection config options - see constructor
 141         public $mConnOptions = array();
 142         /// Statement config options -- see constructor
 143         public $mStmtOptions = array();
 144
 145
 146         const CATALOGED = "cataloged";
 147         const UNCATALOGED = "uncataloged";
 148         const USE_GLOBAL = "get from global";
 149
 150         const NONE_OPTION = 0x00;
 151         const CONN_OPTION = 0x01;
 152         const STMT_OPTION = 0x02;
 153
 154         const REGULAR_MODE = 'regular';
 155         const INSTALL_MODE = 'install';
 156
 157         // Whether this is regular operation or the initial installation
 158         protected $mMode = self::REGULAR_MODE;
 159
 160         /// Last sequence value used for a primary key
 161         protected $mInsertId = null;
 162
 163         /*
 164          * These can be safely inherited
 165          *
 166          * Getter/Setter: (18)
 167          * failFunction
 168          * setOutputPage
 169          * bufferResults
 170          * ignoreErrors
 171          * trxLevel
 172          * errorCount
 173          * getLBInfo
 174          * setLBInfo
 175          * lastQuery
 176          * isOpen
 177          * setFlag
 178          * clearFlag
 179          * getFlag
 180          * getProperty
 181          * getDBname
 182          * getServer
 183          * tableNameCallback
 184          * tablePrefix
 185          *
 186          * Administrative: (8)
 187          * debug
 188          * installErrorHandler
 189          * restoreErrorHandler
 190          * connectionErrorHandler
 191          * reportConnectionError
 192          * sourceFile
 193          * sourceStream
 194          * replaceVars
 195          *
 196          * Database: (5)
 197          * query
 198          * set
 199          * selectField
 200          * generalizeSQL
 201          * update
 202          * strreplace
 203          * deadlockLoop
 204          *
 205          * Prepared Statement: 6
 206          * prepare
 207          * freePrepared
 208          * execute
 209          * safeQuery
 210          * fillPrepared
 211          * fillPreparedArg
 212          *
 213          * Slave/Master: (4)
 214          * masterPosWait
 215          * getSlavePos
 216          * getMasterPos
 217          * getLag
 218          *
 219          * Generation: (9)
 220          * tableNames
 221          * tableNamesN
 222          * tableNamesWithUseIndexOrJOIN
 223          * escapeLike
 224          * delete
 225          * insertSelect
 226          * timestampOrNull
 227          * resultObject
 228          * aggregateValue
 229          * selectSQLText
 230          * selectRow
 231          * makeUpdateOptions
 232          *
 233          * Reflection: (1)
 234          * indexExists
 235          */
 236
 237         /*
 238          * These have been implemented
 239          *
 240          * Administrative: 7 / 7
 241          * constructor [Done]
 242          * open [Done]
 243          * openCataloged [Done]
 244          * close [Done]
 245          * newFromParams [Done]
 246          * openUncataloged [Done]
 247          * setup_database [Done]
 248          *
 249          * Getter/Setter: 13 / 13
 250          * cascadingDeletes [Done]
 251          * cleanupTriggers  [Done]
 252          * strictIPs  [Done]
 253          * realTimestamps  [Done]
 254          * impliciGroupby  [Done]
 255          * implicitOrderby  [Done]
 256          * searchableIPs  [Done]
 257          * functionalIndexes  [Done]
 258          * getWikiID  [Done]
 259          * isOpen [Done]
 260          * getServerVersion [Done]
 261          * getSoftwareLink [Done]
 262          * getSearchEngine [Done]
 263          *
 264          * Database driver wrapper: 23 / 23
 265          * lastError [Done]
 266          * lastErrno [Done]
 267          * doQuery [Done]
 268          * tableExists [Done]
 269          * fetchObject [Done]
 270          * fetchRow [Done]
 271          * freeResult [Done]
 272          * numRows [Done]
 273          * numFields [Done]
 274          * fieldName [Done]
 275          * insertId [Done]
 276          * dataSeek [Done]
 277          * affectedRows [Done]
 278          * selectDB [Done]
 279          * strencode [Done]
 280          * conditional [Done]
 281          * wasDeadlock [Done]
 282          * ping [Done]
 283          * getStatus [Done]
 284          * setTimeout [Done]
 285          * lock [Done]
 286          * unlock [Done]
 287          * insert [Done]
 288          * select [Done]
 289          *
 290          * Slave/master: 2 / 2
 291          * setFakeSlaveLag [Done]
 292          * setFakeMaster [Done]
 293          *
 294          * Reflection: 6 / 6
 295          * fieldExists [Done]
 296          * indexInfo [Done]
 297          * fieldInfo [Done]
 298          * fieldType [Done]
 299          * indexUnique [Done]
 300          * textFieldSize [Done]
 301          *
 302          * Generation: 16 / 16
 303          * tableName [Done]
 304          * addQuotes [Done]
 305          * makeList [Done]
 306          * makeSelectOptions [Done]
 307          * estimateRowCount [Done]
 308          * nextSequenceValue [Done]
 309          * useIndexClause [Done]
 310          * replace [Done]
 311          * deleteJoin [Done]
 312          * lowPriorityOption [Done]
 313          * limitResult [Done]
 314          * limitResultForUpdate [Done]
 315          * timestamp [Done]
 316          * encodeBlob [Done]
 317          * decodeBlob [Done]
 318          * buildConcat [Done]
 319          */
 320
 321         ######################################
 322         # Getters and Setters
 323         ######################################
 324
 325         /**
 326          * Returns true if this database supports (and uses) cascading deletes
 327          */
 328         function cascadingDeletes() {
 329                 return true;
 330         }
 331
 332         /**
 333          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 334          */
 335         function cleanupTriggers() {
 336                 return true;
 337         }
 338
 339         /**
 340          * Returns true if this database is strict about what can be put into an IP field.
 341          * Specifically, it uses a NULL value instead of an empty string.
 342          */
 343         function strictIPs() {
 344                 return true;
 345         }
 346
 347         /**
 348          * Returns true if this database uses timestamps rather than integers
 349         */
 350         function realTimestamps() {
 351                 return true;
 352         }
 353
 354         /**
 355          * Returns true if this database does an implicit sort when doing GROUP BY
 356          */
 357         function implicitGroupby() {
 358                 return false;
 359         }
 360
 361         /**
 362          * Returns true if this database does an implicit order by when the column has an index
 363          * For example: SELECT page_title FROM page LIMIT 1
 364          */
 365         function implicitOrderby() {
 366                 return false;
 367         }
 368
 369         /**
 370          * Returns true if this database can do a native search on IP columns
 371          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 372          */
 373         function searchableIPs() {
 374                 return true;
 375         }
 376
 377         /**
 378          * Returns true if this database can use functional indexes
 379          */
 380         function functionalIndexes() {
 381                 return true;
 382         }
 383
 384         /**
 385          * Returns a unique string representing the wiki on the server
 386          */
 387         function getWikiID() {
 388                 if( $this->mSchema ) {
 389                         return "{$this->mDBname}-{$this->mSchema}";
 390                 } else {
 391                         return $this->mDBname;
 392                 }
 393         }
 394
 395
 396         ######################################
 397         # Setup
 398         ######################################
 399
 400
 401         /**
 402          *
 403          * @param string $server hostname of database server
 404          * @param string $user username
 405          * @param string $password
 406          * @param string $dbName database name on the server
 407          * @param function $failFunction (optional)
 408          * @param integer $flags database behaviour flags (optional, unused)
 409          */
 410         public function DatabaseIbm_db2($server = false, $user = false, $password = false,
 411                                                         $dbName = false, $failFunction = false, $flags = 0,
 412                                                         $schema = self::USE_GLOBAL )
 413         {
 414
 415                 global $wgOut, $wgDBmwschema;
 416                 # Can't get a reference if it hasn't been set yet
 417                 if ( !isset( $wgOut ) ) {
 418                         $wgOut = null;
 419                 }
 420                 $this->mOut =& $wgOut;
 421                 $this->mFailFunction = $failFunction;
 422                 $this->mFlags = DBO_TRX | $flags;
 423
 424                 if ( $schema == self::USE_GLOBAL ) {
 425                         $this->mSchema = $wgDBmwschema;
 426                 }
 427                 else {
 428                         $this->mSchema = $schema;
 429                 }
 430
 431                 // configure the connection and statement objects
 432                 $this->setDB2Option('db2_attr_case', 'DB2_CASE_LOWER', self::CONN_OPTION | self::STMT_OPTION);
 433                 $this->setDB2Option('deferred_prepare', 'DB2_DEFERRED_PREPARE_ON', self::STMT_OPTION);
 434                 $this->setDB2Option('rowcount', 'DB2_ROWCOUNT_PREFETCH_ON', self::STMT_OPTION);
 435
 436                 $this->open( $server, $user, $password, $dbName);
 437         }
 438
 439         /**
 440          * Enables options only if the ibm_db2 extension version supports them
 441          * @param string $name Name of the option in the options array
 442          * @param string $const Name of the constant holding the right option value
 443          * @param int $type Whether this is a Connection or Statement otion
 444          */
 445         private function setDB2Option($name, $const, $type) {
 446                 if (defined($const)) {
 447                         if ($type & self::CONN_OPTION) $this->mConnOptions[$name] = constant($const);
 448                         if ($type & self::STMT_OPTION) $this->mStmtOptions[$name] = constant($const);
 449                 }
 450                 else {
 451                         $this->installPrint("$const is not defined. ibm_db2 version is likely too low.");
 452                 }
 453         }
 454
 455         /**
 456          * Outputs debug information in the appropriate place
 457          * @param string $string The relevant debug message
 458          */
 459         private function installPrint($string) {
 460                 wfDebug("$string");
 461                 if ($this->mMode == self::INSTALL_MODE) {
 462                         print "<li>$string</li>";
 463                         flush();
 464                 }
 465         }
 466
 467         /**
 468          * Opens a database connection and returns it
 469          * Closes any existing connection
 470          * @return a fresh connection
 471          * @param string $server hostname
 472          * @param string $user
 473          * @param string $password
 474          * @param string $dbName database name
 475          */
 476         public function open( $server, $user, $password, $dbName )
 477         {
 478                 // Load the port number
 479                 global $wgDBport_db2, $wgDBcataloged;
 480                 wfProfileIn( __METHOD__ );
 481
 482                 // Load IBM DB2 driver if missing
 483                 if (!@extension_loaded('ibm_db2')) {
 484                         @dl('ibm_db2.so');
 485                 }
 486                 // Test for IBM DB2 support, to avoid suppressed fatal error
 487                 if ( !function_exists( 'db2_connect' ) ) {
 488                         $error = "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?\n";
 489                         $this->installPrint($error);
 490                         $this->reportConnectionError($error);
 491                 }
 492
 493                 if (!strlen($user)) { // Copied from Postgres
 494                         return null;
 495                 }
 496
 497                 // Close existing connection
 498                 $this->close();
 499                 // Cache conn info
 500                 $this->mServer = $server;
 501                 $this->mPort = $port = $wgDBport_db2;
 502                 $this->mUser = $user;
 503                 $this->mPassword = $password;
 504                 $this->mDBname = $dbName;
 505                 $this->mCataloged = $cataloged = $wgDBcataloged;
 506
 507                 if ( $cataloged == self::CATALOGED ) {
 508                         $this->openCataloged($dbName, $user, $password);
 509                 }
 510                 elseif ( $cataloged == self::UNCATALOGED ) {
 511                         $this->openUncataloged($dbName, $user, $password, $server, $port);
 512                 }
 513                 // Apply connection config
 514                 db2_set_option($this->mConn, $this->mConnOptions, 1);
 515                 // Not all MediaWiki code is transactional
 516                 // Rather, turn autocommit off in the begin function and turn on after a commit
 517                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 518
 519                 if ( $this->mConn == false ) {
 520                         $this->installPrint( "DB connection error\n" );
 521                         $this->installPrint( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 522                         $this->installPrint( $this->lastError()."\n" );
 523                         return null;
 524                 }
 525
 526                 $this->mOpened = true;
 527                 $this->applySchema();
 528
 529                 wfProfileOut( __METHOD__ );
 530                 return $this->mConn;
 531         }
 532
 533         /**
 534          * Opens a cataloged database connection, sets mConn
 535          */
 536         protected function openCataloged( $dbName, $user, $password )
 537         {
 538                 @$this->mConn = db2_connect($dbName, $user, $password);
 539         }
 540
 541         /**
 542          * Opens an uncataloged database connection, sets mConn
 543          */
 544         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 545         {
 546                 $str = "DRIVER={IBM DB2 ODBC DRIVER};";
 547                 $str .= "DATABASE=$dbName;";
 548                 $str .= "HOSTNAME=$server;";
 549                 if ($port) $str .= "PORT=$port;";
 550                 $str .= "PROTOCOL=TCPIP;";
 551                 $str .= "UID=$user;";
 552                 $str .= "PWD=$password;";
 553
 554                 @$this->mConn = db2_connect($str, $user, $password);
 555         }
 556
 557         /**
 558          * Closes a database connection, if it is open
 559          * Returns success, true if already closed
 560          */
 561         public function close() {
 562                 $this->mOpened = false;
 563                 if ( $this->mConn ) {
 564                         if ($this->trxLevel() > 0) {
 565                                 $this->commit();
 566                         }
 567                         return db2_close( $this->mConn );
 568                 }
 569                 else {
 570                         return true;
 571                 }
 572         }
 573
 574         /**
 575          * Returns a fresh instance of this class
 576          * @static
 577          * @return
 578          * @param string $server hostname of database server
 579          * @param string $user username
 580          * @param string $password
 581          * @param string $dbName database name on the server
 582          * @param function $failFunction (optional)
 583          * @param integer $flags database behaviour flags (optional, unused)
 584          */
 585         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0)
 586         {
 587                 return new DatabaseIbm_db2( $server, $user, $password, $dbName, $failFunction, $flags );
 588         }
 589
 590         /**
 591          * Retrieves the most current database error
 592          * Forces a database rollback
 593          */
 594         public function lastError() {
 595                 $connerr = db2_conn_errormsg();
 596                 if ($connerr) {
 597                         //$this->rollback();
 598                         return $connerr;
 599                 }
 600                 $stmterr = db2_stmt_errormsg();
 601                 if ($stmterr) {
 602                         //$this->rollback();
 603                         return $stmterr;
 604                 }
 605
 606                 return false;
 607         }
 608
 609         /**
 610          * Get the last error number
 611          * Return 0 if no error
 612          * @return integer
 613          */
 614         public function lastErrno() {
 615                 $connerr = db2_conn_error();
 616                 if ($connerr) return $connerr;
 617                 $stmterr = db2_stmt_error();
 618                 if ($stmterr) return $stmterr;
 619                 return 0;
 620         }
 621
 622         /**
 623          * Is a database connection open?
 624          * @return
 625          */
 626         public function isOpen() { return $this->mOpened; }
 627
 628         /**
 629          * The DBMS-dependent part of query()
 630          * @param  $sql String: SQL query.
 631          * @return object Result object to feed to fetchObject, fetchRow, ...; or false on failure
 632          * @access private
 633          */
 634         /*private*/
 635         public function doQuery( $sql ) {
 636                 //print "<li><pre>$sql</pre></li>";
 637                 // Switch into the correct namespace
 638                 $this->applySchema();
 639
 640                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 641                 if( !$ret ) {
 642                         print "<br><pre>";
 643                         print $sql;
 644                         print "</pre><br>";
 645                         $error = db2_stmt_errormsg();
 646                         throw new DBUnexpectedError($this,  'SQL error: ' . htmlspecialchars( $error ) );
 647                 }
 648                 $this->mLastResult = $ret;
 649                 $this->mAffectedRows = null;    // Not calculated until asked for
 650                 return $ret;
 651         }
 652
 653         /**
 654          * @return string Version information from the database
 655          */
 656         public function getServerVersion() {
 657                 $info = db2_server_info( $this->mConn );
 658                 return $info->DBMS_VER;
 659         }
 660
 661         /**
 662          * Queries whether a given table exists
 663          * @return boolean
 664          */
 665         public function tableExists( $table ) {
 666                 $schema = $this->mSchema;
 667                 $sql = <<< EOF
 668 SELECT COUNT(*) FROM SYSIBM.SYSTABLES ST
 669 WHERE ST.NAME = '$table' AND ST.CREATOR = '$schema'
 670 EOF;
 671                 $res = $this->query( $sql );
 672                 if (!$res) return false;
 673
 674                 // If the table exists, there should be one of it
 675                 @$row = $this->fetchRow($res);
 676                 $count = $row[0];
 677                 if ($count == '1' or $count == 1) {
 678                         return true;
 679                 }
 680
 681                 return false;
 682         }
 683
 684         /**
 685          * Fetch the next row from the given result object, in object form.
 686          * Fields can be retrieved with $row->fieldname, with fields acting like
 687          * member variables.
 688          *
 689          * @param $res SQL result object as returned from Database::query(), etc.
 690          * @return DB2 row object
 691          * @throws DBUnexpectedError Thrown if the database returns an error
 692          */
 693         public function fetchObject( $res ) {
 694                 if ( $res instanceof ResultWrapper ) {
 695                         $res = $res->result;
 696                 }
 697                 @$row = db2_fetch_object( $res );
 698                 if( $this->lastErrno() ) {
 699                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 700                 }
 701                 return $row;
 702         }
 703
 704         /**
 705          * Fetch the next row from the given result object, in associative array
 706          * form.  Fields are retrieved with $row['fieldname'].
 707          *
 708          * @param $res SQL result object as returned from Database::query(), etc.
 709          * @return DB2 row object
 710          * @throws DBUnexpectedError Thrown if the database returns an error
 711          */
 712         public function fetchRow( $res ) {
 713                 if ( $res instanceof ResultWrapper ) {
 714                         $res = $res->result;
 715                 }
 716                 @$row = db2_fetch_array( $res );
 717                 if ( $this->lastErrno() ) {
 718                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 719                 }
 720                 return $row;
 721         }
 722
 723         /**
 724          * Override if introduced to base Database class
 725          */
 726         public function initial_setup() {
 727                 // do nothing
 728         }
 729
 730         /**
 731          * Create tables, stored procedures, and so on
 732          */
 733         public function setup_database() {
 734                 // Timeout was being changed earlier due to mysterious crashes
 735                 // Changing it now may cause more problems than not changing it
 736                 //set_time_limit(240);
 737                 try {
 738                         // TODO: switch to root login if available
 739
 740                         // Switch into the correct namespace
 741                         $this->applySchema();
 742                         $this->begin();
 743
 744                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 745                         $res = null;
 746
 747                         // TODO: update mediawiki_version table
 748
 749                         // TODO: populate interwiki links
 750
 751                         if ($this->lastError()) {
 752                                 print "<li>Errors encountered during table creation -- rolled back</li>\n";
 753                                 print "<li>Please install again</li>\n";
 754                                 $this->rollback();
 755                         }
 756                         else {
 757                                 $this->commit();
 758                         }
 759                 }
 760                 catch (MWException $mwe)
 761                 {
 762                         print "<br><pre>$mwe</pre><br>";
 763                 }
 764         }
 765
 766         /**
 767          * Escapes strings
 768          * Doesn't escape numbers
 769          * @param string s string to escape
 770          * @return escaped string
 771          */
 772         public function addQuotes( $s ) {
 773                 //$this->installPrint("DB2::addQuotes($s)\n");
 774                 if ( is_null( $s ) ) {
 775                         return "NULL";
 776                 } else if ($s instanceof Blob) {
 777                         return "'".$s->fetch($s)."'";
 778                 } else if ($s instanceof IBM_DB2Blob) {
 779                         return "'".$this->decodeBlob($s)."'";
 780                 }
 781                 $s = $this->strencode($s);
 782                 if ( is_numeric($s) ) {
 783                         return $s;
 784                 }
 785                 else {
 786                         return "'$s'";
 787                 }
 788         }
 789
 790         /**
 791          * Verifies that a DB2 column/field type is numeric
 792          * @return bool true if numeric
 793          * @param string $type DB2 column type
 794          */
 795         public function is_numeric_type( $type ) {
 796                 switch (strtoupper($type)) {
 797                 case 'SMALLINT':
 798                 case 'INTEGER':
 799                 case 'INT':
 800                 case 'BIGINT':
 801                 case 'DECIMAL':
 802                 case 'REAL':
 803                 case 'DOUBLE':
 804                 case 'DECFLOAT':
 805                         return true;
 806                 }
 807                 return false;
 808         }
 809
 810         /**
 811          * Alias for addQuotes()
 812          * @param string s string to escape
 813          * @return escaped string
 814          */
 815         public function strencode( $s ) {
 816                 // Bloody useless function
 817                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 818                 //  But also necessary
 819                 $s = db2_escape_string($s);
 820                 // Wide characters are evil -- some of them look like '
 821                 $s = utf8_encode($s);
 822                 // Fix its stupidity
 823                 $from = array("\\\\",   "\\'",  '\\n',  '\\t',  '\\"',  '\\r');
 824                 $to =   array("\\",             "''",   "\n",   "\t",   '"',    "\r");
 825                 $s = str_replace($from, $to, $s); // DB2 expects '', not \' escaping
 826                 return $s;
 827         }
 828
 829         /**
 830          * Switch into the database schema
 831          */
 832         protected function applySchema() {
 833                 if ( !($this->mSchemaSet) ) {
 834                         $this->mSchemaSet = true;
 835                         $this->begin();
 836                         $this->doQuery("SET SCHEMA = $this->mSchema");
 837                         $this->commit();
 838                 }
 839         }
 840
 841         /**
 842          * Start a transaction (mandatory)
 843          */
 844         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 845                 // turn off auto-commit
 846                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_OFF);
 847                 $this->mTrxLevel = 1;
 848         }
 849
 850         /**
 851          * End a transaction
 852          * Must have a preceding begin()
 853          */
 854         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 855                 db2_commit($this->mConn);
 856                 // turn auto-commit back on
 857                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 858                 $this->mTrxLevel = 0;
 859         }
 860
 861         /**
 862          * Cancel a transaction
 863          */
 864         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 865                 db2_rollback($this->mConn);
 866                 // turn auto-commit back on
 867                 // not sure if this is appropriate
 868                 db2_autocommit($this->mConn, DB2_AUTOCOMMIT_ON);
 869                 $this->mTrxLevel = 0;
 870         }
 871
 872         /**
 873          * Makes an encoded list of strings from an array
 874          * $mode:
 875          *        LIST_COMMA         - comma separated, no field names
 876          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
 877          *        LIST_OR            - ORed WHERE clause (without the WHERE)
 878          *        LIST_SET           - comma separated with field names, like a SET clause
 879          *        LIST_NAMES         - comma separated field names
 880          */
 881         public function makeList( $a, $mode = LIST_COMMA ) {
 882                 if ( !is_array( $a ) ) {
 883                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
 884                 }
 885
 886                 $first = true;
 887                 $list = '';
 888                 foreach ( $a as $field => $value ) {
 889                         if ( !$first ) {
 890                                 if ( $mode == LIST_AND ) {
 891                                         $list .= ' AND ';
 892                                 } elseif($mode == LIST_OR) {
 893                                         $list .= ' OR ';
 894                                 } else {
 895                                         $list .= ',';
 896                                 }
 897                         } else {
 898                                 $first = false;
 899                         }
 900                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
 901                                 $list .= "($value)";
 902                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
 903                                 $list .= "$value";
 904                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
 905                                 if( count( $value ) == 0 ) {
 906                                         throw new MWException( __METHOD__.': empty input' );
 907                                 } elseif( count( $value ) == 1 ) {
 908                                         // Special-case single values, as IN isn't terribly efficient
 909                                         // Don't necessarily assume the single key is 0; we don't
 910                                         // enforce linear numeric ordering on other arrays here.
 911                                         $value = array_values( $value );
 912                                         $list .= $field." = ".$this->addQuotes( $value[0] );
 913                                 } else {
 914                                         $list .= $field." IN (".$this->makeList($value).") ";
 915                                 }
 916                         } elseif( is_null($value) ) {
 917                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
 918                                         $list .= "$field IS ";
 919                                 } elseif ( $mode == LIST_SET ) {
 920                                         $list .= "$field = ";
 921                                 }
 922                                 $list .= 'NULL';
 923                         } else {
 924                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
 925                                         $list .= "$field = ";
 926                                 }
 927                                 if ( $mode == LIST_NAMES ) {
 928                                         $list .= $value;
 929                                 }
 930                                 // Leo: Can't insert quoted numbers into numeric columns
 931                                 // (?) Might cause other problems. May have to check column type before insertion.
 932                                 else if ( is_numeric($value) ) {
 933                                         $list .= $value;
 934                                 }
 935                                 else {
 936                                         $list .= $this->addQuotes( $value );
 937                                 }
 938                         }
 939                 }
 940                 return $list;
 941         }
 942
 943         /**
 944          * Construct a LIMIT query with optional offset
 945          * This is used for query pages
 946          * $sql string SQL query we will append the limit too
 947          * $limit integer the SQL limit
 948          * $offset integer the SQL offset (default false)
 949          */
 950         public function limitResult($sql, $limit, $offset=false) {
 951                 if( !is_numeric($limit) ) {
 952                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
 953                 }
 954                 if( $offset ) {
 955                         $this->installPrint("Offset parameter not supported in limitResult()\n");
 956                 }
 957                 // TODO implement proper offset handling
 958                 // idea: get all the rows between 0 and offset, advance cursor to offset
 959                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 960         }
 961
 962         /**
 963          * Handle reserved keyword replacement in table names
 964          * @return
 965          * @param $name Object
 966          */
 967         public function tableName( $name ) {
 968                 # Replace reserved words with better ones
 969 //              switch( $name ) {
 970 //                      case 'user':
 971 //                              return 'mwuser';
 972 //                      case 'text':
 973 //                              return 'pagecontent';
 974 //                      default:
 975 //                              return $name;
 976 //              }
 977                 // we want maximum compatibility with MySQL schema
 978                 return $name;
 979         }
 980
 981         /**
 982          * Generates a timestamp in an insertable format
 983          * @return string timestamp value
 984          * @param timestamp $ts
 985          */
 986         public function timestamp( $ts=0 ) {
 987                 // TS_MW cannot be easily distinguished from an integer
 988                 return wfTimestamp(TS_DB2,$ts);
 989         }
 990
 991         /**
 992          * Return the next in a sequence, save the value for retrieval via insertId()
 993          * @param string seqName Name of a defined sequence in the database
 994          * @return next value in that sequence
 995          */
 996         public function nextSequenceValue( $seqName ) {
 997                 // Not using sequences in the primary schema to allow for easy third-party migration scripts
 998                 // Emulating MySQL behaviour of using NULL to signal that sequences aren't used
 999                 /*
1000                 $safeseq = preg_replace( "/'/", "''", $seqName );
1001                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
1002                 $row = $this->fetchRow( $res );
1003                 $this->mInsertId = $row[0];
1004                 $this->freeResult( $res );
1005                 return $this->mInsertId;
1006                 */
1007                 return null;
1008         }
1009
1010         /**
1011          * This must be called after nextSequenceVal
1012          * @return Last sequence value used as a primary key
1013          */
1014         public function insertId() {
1015                 return $this->mInsertId;
1016         }
1017
1018         /**
1019          * Updates the mInsertId property with the value of the last insert into a generated column
1020          * @param string        $table          Sanitized table name
1021          * @param mixed         $primaryKey     String name of the primary key or a bool if this call is a do-nothing
1022          * @param resource      $stmt           Prepared statement resource
1023          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
1024          */
1025         private function calcInsertId($table, $primaryKey, $stmt) {
1026                 if ($primaryKey) {
1027                         $id_row = $this->fetchRow($stmt);
1028                         $this->mInsertId = $id_row[0];
1029                 }
1030         }
1031
1032         /**
1033          * INSERT wrapper, inserts an array into a table
1034          *
1035          * $args may be a single associative array, or an array of these with numeric keys,
1036          * for multi-row insert
1037          *
1038          * @param array $table   String: Name of the table to insert to.
1039          * @param array $args    Array: Items to insert into the table.
1040          * @param array $fname   String: Name of the function, for profiling
1041          * @param mixed $options String or Array. Valid options: IGNORE
1042          *
1043          * @return bool Success of insert operation. IGNORE always returns true.
1044          */
1045         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert', $options = array() ) {
1046                 if ( !count( $args ) ) {
1047                         return true;
1048                 }
1049                 // get database-specific table name (not used)
1050                 $table = $this->tableName( $table );
1051                 // format options as an array
1052                 if ( !is_array( $options ) ) $options = array( $options );
1053                 // format args as an array of arrays
1054                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
1055                         $args = array($args);
1056                 }
1057                 // prevent insertion of NULL into primary key columns
1058                 list($args, $primaryKeys) = $this->removeNullPrimaryKeys($table, $args);
1059                 // if there's only one primary key
1060                 // we'll be able to read its value after insertion
1061                 $primaryKey = false;
1062                 if (count($primaryKeys) == 1) {
1063                         $primaryKey = $primaryKeys[0];
1064                 }
1065
1066                 // get column names
1067                 $keys = array_keys( $args[0] );
1068                 $key_count = count($keys);
1069
1070                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
1071                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
1072
1073                 // assume success
1074                 $res = true;
1075                 // If we are not in a transaction, we need to be for savepoint trickery
1076                 $didbegin = 0;
1077                 if (! $this->mTrxLevel) {
1078                         $this->begin();
1079                         $didbegin = 1;
1080                 }
1081
1082                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1083                 switch($key_count) {
1084                         //case 0 impossible
1085                         case 1:
1086                                 $sql .= '(?)';
1087                                 break;
1088                         default:
1089                                 $sql .= '(?' . str_repeat(',?', $key_count-1) . ')';
1090                 }
1091                 // add logic to read back the new primary key value
1092                 if ($primaryKey) {
1093                         $sql = "SELECT $primaryKey FROM FINAL TABLE($sql)";
1094                 }
1095                 $stmt = $this->prepare($sql);
1096
1097                 // start a transaction/enter transaction mode
1098                 $this->begin();
1099
1100                 if ( !$ignore ) {
1101                         $first = true;
1102                         foreach ( $args as $row ) {
1103                                 // insert each row into the database
1104                                 $res = $res & $this->execute($stmt, $row);
1105                                 // get the last inserted value into a generated column
1106                                 $this->calcInsertId($table, $primaryKey, $stmt);
1107                         }
1108                 }
1109                 else {
1110                         $olde = error_reporting( 0 );
1111                         // For future use, we may want to track the number of actual inserts
1112                         // Right now, insert (all writes) simply return true/false
1113                         $numrowsinserted = 0;
1114
1115                         // always return true
1116                         $res = true;
1117
1118                         foreach ( $args as $row ) {
1119                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
1120                                 db2_exec($this->mConn, $overhead, $this->mStmtOptions);
1121
1122                                 $res2 = $this->execute($stmt, $row);
1123                                 // get the last inserted value into a generated column
1124                                 $this->calcInsertId($table, $primaryKey, $stmt);
1125
1126                                 $errNum = $this->lastErrno();
1127                                 if ($errNum) {
1128                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore", $this->mStmtOptions );
1129                                 }
1130                                 else {
1131                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore", $this->mStmtOptions );
1132                                         $numrowsinserted++;
1133                                 }
1134                         }
1135
1136                         $olde = error_reporting( $olde );
1137                         // Set the affected row count for the whole operation
1138                         $this->mAffectedRows = $numrowsinserted;
1139                 }
1140                 // commit either way
1141                 $this->commit();
1142
1143                 return $res;
1144         }
1145
1146         /**
1147          * Given a table name and a hash of columns with values
1148          * Removes primary key columns from the hash where the value is NULL
1149          *
1150          * @param string $table Name of the table
1151          * @param array $args Array of hashes of column names with values
1152          * @return array Tuple containing filtered array of columns, array of primary keys
1153          */
1154         private function removeNullPrimaryKeys($table, $args) {
1155                 $schema = $this->mSchema;
1156                 // find out the primary keys
1157                 $keyres = db2_primary_keys($this->mConn, null, strtoupper($schema), strtoupper($table));
1158                 $keys = array();
1159                 for ($row = $this->fetchObject($keyres); $row != null; $row = $this->fetchRow($keyres)) {
1160                         $keys[] = strtolower($row->column_name);
1161                 }
1162                 // remove primary keys
1163                 foreach ($args as $ai => $row) {
1164                         foreach ($keys as $ki => $key) {
1165                                 if ($row[$key] == null) {
1166                                         unset($row[$key]);
1167                                 }
1168                         }
1169                         $args[$ai] = $row;
1170                 }
1171                 // return modified hash
1172                 return array($args, $keys);
1173         }
1174
1175         /**
1176          * UPDATE wrapper, takes a condition array and a SET array
1177          *
1178          * @param string $table  The table to UPDATE
1179          * @param array  $values An array of values to SET
1180          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1181          * @param string $fname  The Class::Function calling this function
1182          *                       (for the log)
1183          * @param array  $options An array of UPDATE options, can be one or
1184          *                        more of IGNORE, LOW_PRIORITY
1185          * @return bool
1186          */
1187         public function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1188                 $table = $this->tableName( $table );
1189                 $opts = $this->makeUpdateOptions( $options );
1190                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1191                 if ( $conds != '*' ) {
1192                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1193                 }
1194                 return $this->query( $sql, $fname );
1195         }
1196
1197         /**
1198          * DELETE query wrapper
1199          *
1200          * Use $conds == "*" to delete all rows
1201          */
1202         public function delete( $table, $conds, $fname = 'Database::delete' ) {
1203                 if ( !$conds ) {
1204                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1205                 }
1206                 $table = $this->tableName( $table );
1207                 $sql = "DELETE FROM $table";
1208                 if ( $conds != '*' ) {
1209                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1210                 }
1211                 return $this->query( $sql, $fname );
1212         }
1213
1214         /**
1215          * Returns the number of rows affected by the last query or 0
1216          * @return int the number of rows affected by the last query
1217          */
1218         public function affectedRows() {
1219                 if ( !is_null( $this->mAffectedRows ) ) {
1220                         // Forced result for simulated queries
1221                         return $this->mAffectedRows;
1222                 }
1223                 if( empty( $this->mLastResult ) )
1224                         return 0;
1225                 return db2_num_rows( $this->mLastResult );
1226         }
1227
1228         /**
1229          * Simulates REPLACE with a DELETE followed by INSERT
1230          * @param $table Object
1231          * @param array $uniqueIndexes array consisting of indexes and arrays of indexes
1232          * @param array $rows Rows to insert
1233          * @param string $fname Name of the function for profiling
1234          * @return nothing
1235          */
1236         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseIbm_db2::replace' ) {
1237                 $table = $this->tableName( $table );
1238
1239                 if (count($rows)==0) {
1240                         return;
1241                 }
1242
1243                 # Single row case
1244                 if ( !is_array( reset( $rows ) ) ) {
1245                         $rows = array( $rows );
1246                 }
1247
1248                 foreach( $rows as $row ) {
1249                         # Delete rows which collide
1250                         if ( $uniqueIndexes ) {
1251                                 $sql = "DELETE FROM $table WHERE ";
1252                                 $first = true;
1253                                 foreach ( $uniqueIndexes as $index ) {
1254                                         if ( $first ) {
1255                                                 $first = false;
1256                                                 $sql .= "(";
1257                                         } else {
1258                                                 $sql .= ') OR (';
1259                                         }
1260                                         if ( is_array( $index ) ) {
1261                                                 $first2 = true;
1262                                                 foreach ( $index as $col ) {
1263                                                         if ( $first2 ) {
1264                                                                 $first2 = false;
1265                                                         } else {
1266                                                                 $sql .= ' AND ';
1267                                                         }
1268                                                         $sql .= $col.'=' . $this->addQuotes( $row[$col] );
1269                                                 }
1270                                         } else {
1271                                                 $sql .= $index.'=' . $this->addQuotes( $row[$index] );
1272                                         }
1273                                 }
1274                                 $sql .= ')';
1275                                 $this->query( $sql, $fname );
1276                         }
1277
1278                         # Now insert the row
1279                         $sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
1280                                 $this->makeList( $row, LIST_COMMA ) . ')';
1281                         $this->query( $sql, $fname );
1282                 }
1283         }
1284
1285         /**
1286          * Returns the number of rows in the result set
1287          * Has to be called right after the corresponding select query
1288          * @param object $res result set
1289          * @return int number of rows
1290          */
1291         public function numRows( $res ) {
1292                 if ( $res instanceof ResultWrapper ) {
1293                         $res = $res->result;
1294                 }
1295                 if ( $this->mNumRows ) {
1296                         return $this->mNumRows;
1297                 }
1298                 else {
1299                         return 0;
1300                 }
1301         }
1302
1303         /**
1304          * Moves the row pointer of the result set
1305          * @param object $res result set
1306          * @param int $row row number
1307          * @return success or failure
1308          */
1309         public function dataSeek( $res, $row ) {
1310                 if ( $res instanceof ResultWrapper ) {
1311                         $res = $res->result;
1312                 }
1313                 return db2_fetch_row( $res, $row );
1314         }
1315
1316         ###
1317         # Fix notices in Block.php
1318         ###
1319
1320         /**
1321          * Frees memory associated with a statement resource
1322          * @param object $res Statement resource to free
1323          * @return bool success or failure
1324          */
1325         public function freeResult( $res ) {
1326                 if ( $res instanceof ResultWrapper ) {
1327                         $res = $res->result;
1328                 }
1329                 if ( !@db2_free_result( $res ) ) {
1330                         throw new DBUnexpectedError($this,  "Unable to free DB2 result\n" );
1331                 }
1332         }
1333
1334         /**
1335          * Returns the number of columns in a resource
1336          * @param object $res Statement resource
1337          * @return Number of fields/columns in resource
1338          */
1339         public function numFields( $res ) {
1340                 if ( $res instanceof ResultWrapper ) {
1341                         $res = $res->result;
1342                 }
1343                 return db2_num_fields( $res );
1344         }
1345
1346         /**
1347          * Returns the nth column name
1348          * @param object $res Statement resource
1349          * @param int $n Index of field or column
1350          * @return string name of nth column
1351          */
1352         public function fieldName( $res, $n ) {
1353                 if ( $res instanceof ResultWrapper ) {
1354                         $res = $res->result;
1355                 }
1356                 return db2_field_name( $res, $n );
1357         }
1358
1359         /**
1360          * SELECT wrapper
1361          *
1362          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
1363          * @param mixed  $vars    Array or string, field name(s) to be retrieved
1364          * @param mixed  $conds   Array or string, condition(s) for WHERE
1365          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
1366          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1367          *                        see Database::makeSelectOptions code for list of supported stuff
1368          * @param array $join_conds Associative array of table join conditions (optional)
1369          *                        (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
1370          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
1371          */
1372         public function select( $table, $vars, $conds='', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1373         {
1374                 $res = parent::select( $table, $vars, $conds, $fname, $options, $join_conds );
1375
1376                 // We must adjust for offset
1377                 if ( isset( $options['LIMIT'] ) ) {
1378                         if ( isset ($options['OFFSET'] ) ) {
1379                                 $limit = $options['LIMIT'];
1380                                 $offset = $options['OFFSET'];
1381                         }
1382                 }
1383
1384
1385                 // DB2 does not have a proper num_rows() function yet, so we must emulate it
1386                 // DB2 9.5.3/9.5.4 and the corresponding ibm_db2 driver will introduce a working one
1387                 // Yay!
1388
1389                 // we want the count
1390                 $vars2 = array('count(*) as num_rows');
1391                 // respecting just the limit option
1392                 $options2 = array();
1393                 if ( isset( $options['LIMIT'] ) ) $options2['LIMIT'] = $options['LIMIT'];
1394                 // but don't try to emulate for GROUP BY
1395                 if ( isset( $options['GROUP BY'] ) ) return $res;
1396
1397                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2, $join_conds );
1398                 $obj = $this->fetchObject($res2);
1399                 $this->mNumRows = $obj->num_rows;
1400
1401
1402                 return $res;
1403         }
1404
1405         /**
1406          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1407          * Has limited support for per-column options (colnum => 'DISTINCT')
1408          *
1409          * @private
1410          *
1411          * @param array $options an associative array of options to be turned into
1412          *              an SQL query, valid keys are listed in the function.
1413          * @return array
1414          */
1415         function makeSelectOptions( $options ) {
1416                 $preLimitTail = $postLimitTail = '';
1417                 $startOpts = '';
1418
1419                 $noKeyOptions = array();
1420                 foreach ( $options as $key => $option ) {
1421                         if ( is_numeric( $key ) ) {
1422                                 $noKeyOptions[$option] = true;
1423                         }
1424                 }
1425
1426                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1427                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
1428                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1429
1430                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
1431
1432                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1433         }
1434
1435         /**
1436          * Returns link to IBM DB2 free download
1437          * @return string wikitext of a link to the server software's web site
1438          */
1439         public function getSoftwareLink() {
1440                 return "[http://www.ibm.com/software/data/db2/express/?s_cmp=ECDDWW01&s_tact=MediaWiki IBM DB2]";
1441         }
1442
1443         /**
1444          * Get search engine class. All subclasses of this
1445          * need to implement this if they wish to use searching.
1446          *
1447          * @return string
1448          */
1449         public function getSearchEngine() {
1450                 return "SearchIBM_DB2";
1451         }
1452
1453         /**
1454          * Did the last database access fail because of deadlock?
1455          * @return bool
1456          */
1457         public function wasDeadlock() {
1458                 // get SQLSTATE
1459                 $err = $this->lastErrno();
1460                 switch($err) {
1461                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1462                         case '57011':   // sql0904n, Resource unavailable, no rollback
1463                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1464                         $this->installPrint("In a deadlock because of SQLSTATE $err");
1465                         return true;
1466                 }
1467                 return false;
1468         }
1469
1470         /**
1471          * Ping the server and try to reconnect if it there is no connection
1472          * The connection may be closed and reopened while this happens
1473          * @return bool whether the connection exists
1474          */
1475         public function ping() {
1476                 // db2_ping() doesn't exist
1477                 // Emulate
1478                 $this->close();
1479                 if ($this->mCataloged == null) {
1480                         return false;
1481                 }
1482                 else if ($this->mCataloged) {
1483                         $this->mConn = $this->openCataloged($this->mDBName, $this->mUser, $this->mPassword);
1484                 }
1485                 else if (!$this->mCataloged) {
1486                         $this->mConn = $this->openUncataloged($this->mDBName, $this->mUser, $this->mPassword, $this->mServer, $this->mPort);
1487                 }
1488                 return false;
1489         }
1490         ######################################
1491         # Unimplemented and not applicable
1492         ######################################
1493         /**
1494          * Not implemented
1495          * @return string ''
1496          * @deprecated
1497          */
1498         public function getStatus( $which="%" ) { $this->installPrint('Not implemented for DB2: getStatus()'); return ''; }
1499         /**
1500          * Not implemented
1501          * TODO
1502          * @return bool true
1503          */
1504         /**
1505          * Not implemented
1506          * @deprecated
1507          */
1508         public function setFakeSlaveLag( $lag ) { $this->installPrint('Not implemented for DB2: setFakeSlaveLag()'); }
1509         /**
1510          * Not implemented
1511          * @deprecated
1512          */
1513         public function setFakeMaster( $enabled = true ) { $this->installPrint('Not implemented for DB2: setFakeMaster()'); }
1514         /**
1515          * Not implemented
1516          * @return string $sql
1517          * @deprecated
1518          */
1519         public function limitResultForUpdate($sql, $num) { $this->installPrint('Not implemented for DB2: limitResultForUpdate()'); return $sql; }
1520
1521         /**
1522          * Only useful with fake prepare like in base Database class
1523          * @return      string
1524          */
1525         public function fillPreparedArg( $matches ) { $this->installPrint('Not useful for DB2: fillPreparedArg()'); return ''; }
1526
1527         ######################################
1528         # Reflection
1529         ######################################
1530
1531         /**
1532          * Query whether a given column exists in the mediawiki schema
1533          * @param string $table name of the table
1534          * @param string $field name of the column
1535          * @param string $fname function name for logging and profiling
1536          */
1537         public function fieldExists( $table, $field, $fname = 'DatabaseIbm_db2::fieldExists' ) {
1538                 $table = $this->tableName( $table );
1539                 $schema = $this->mSchema;
1540                 $etable = preg_replace("/'/", "''", $table);
1541                 $eschema = preg_replace("/'/", "''", $schema);
1542                 $ecol = preg_replace("/'/", "''", $field);
1543                 $sql = <<<SQL
1544 SELECT 1 as fieldexists
1545 FROM sysibm.syscolumns sc
1546 WHERE sc.name='$ecol' AND sc.tbname='$etable' AND sc.tbcreator='$eschema'
1547 SQL;
1548                 $res = $this->query( $sql, $fname );
1549                 $count = $res ? $this->numRows($res) : 0;
1550                 if ($res)
1551                         $this->freeResult( $res );
1552                 return $count;
1553         }
1554
1555         /**
1556          * Returns information about an index
1557          * If errors are explicitly ignored, returns NULL on failure
1558          * @param string $table table name
1559          * @param string $index index name
1560          * @param string
1561          * @return object query row in object form
1562          */
1563         public function indexInfo( $table, $index, $fname = 'DatabaseIbm_db2::indexExists' ) {
1564                 $table = $this->tableName( $table );
1565                 $sql = <<<SQL
1566 SELECT name as indexname
1567 FROM sysibm.sysindexes si
1568 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1569 SQL;
1570                 $res = $this->query( $sql, $fname );
1571                 if ( !$res ) {
1572                         return null;
1573                 }
1574                 $row = $this->fetchObject( $res );
1575                 if ($row != null) return $row;
1576                 else return false;
1577         }
1578
1579         /**
1580          * Returns an information object on a table column
1581          * @param string $table table name
1582          * @param string $field column name
1583          * @return IBM_DB2Field
1584          */
1585         public function fieldInfo( $table, $field ) {
1586                 return IBM_DB2Field::fromText($this, $table, $field);
1587         }
1588
1589         /**
1590          * db2_field_type() wrapper
1591          * @param object $res Result of executed statement
1592          * @param mixed $index number or name of the column
1593          * @return string column type
1594          */
1595         public function fieldType( $res, $index ) {
1596                 if ( $res instanceof ResultWrapper ) {
1597                         $res = $res->result;
1598                 }
1599                 return db2_field_type( $res, $index );
1600         }
1601
1602         /**
1603          * Verifies that an index was created as unique
1604          * @param string $table table name
1605          * @param string $index index name
1606          * @param string $fnam function name for profiling
1607          * @return bool
1608          */
1609         public function indexUnique ($table, $index, $fname = 'Database::indexUnique' ) {
1610                 $table = $this->tableName( $table );
1611                 $sql = <<<SQL
1612 SELECT si.name as indexname
1613 FROM sysibm.sysindexes si
1614 WHERE si.name='$index' AND si.tbname='$table' AND sc.tbcreator='$this->mSchema'
1615 AND si.uniquerule IN ('U', 'P')
1616 SQL;
1617                 $res = $this->query( $sql, $fname );
1618                 if ( !$res ) {
1619                         return null;
1620                 }
1621                 if ($this->fetchObject( $res )) {
1622                         return true;
1623                 }
1624                 return false;
1625
1626         }
1627
1628         /**
1629          * Returns the size of a text field, or -1 for "unlimited"
1630          * @param string $table table name
1631          * @param string $field column name
1632          * @return int length or -1 for unlimited
1633          */
1634         public function textFieldSize( $table, $field ) {
1635                 $table = $this->tableName( $table );
1636                 $sql = <<<SQL
1637 SELECT length as size
1638 FROM sysibm.syscolumns sc
1639 WHERE sc.name='$field' AND sc.tbname='$table' AND sc.tbcreator='$this->mSchema'
1640 SQL;
1641                 $res = $this->query($sql);
1642                 $row = $this->fetchObject($res);
1643                 $size = $row->size;
1644                 $this->freeResult( $res );
1645                 return $size;
1646         }
1647
1648         /**
1649          * DELETE where the condition is a join
1650          * @param string $delTable deleting from this table
1651          * @param string $joinTable using data from this table
1652          * @param string $delVar variable in deleteable table
1653          * @param string $joinVar variable in data table
1654          * @param array $conds conditionals for join table
1655          * @param string $fname function name for profiling
1656          */
1657         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = "DatabaseIbm_db2::deleteJoin" ) {
1658                 if ( !$conds ) {
1659                         throw new DBUnexpectedError($this,  'Database::deleteJoin() called with empty $conds' );
1660                 }
1661
1662                 $delTable = $this->tableName( $delTable );
1663                 $joinTable = $this->tableName( $joinTable );
1664                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
1665                 if ( $conds != '*' ) {
1666                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1667                 }
1668                 $sql .= ')';
1669
1670                 $this->query( $sql, $fname );
1671         }
1672
1673         /**
1674          * Description is left as an exercise for the reader
1675          * @param mixed $b data to be encoded
1676          * @return IBM_DB2Blob
1677          */
1678         public function encodeBlob($b) {
1679                 return new IBM_DB2Blob($b);
1680         }
1681
1682         /**
1683          * Description is left as an exercise for the reader
1684          * @param IBM_DB2Blob $b data to be decoded
1685          * @return mixed
1686          */
1687         public function decodeBlob($b) {
1688                 return $b->getData();
1689         }
1690
1691         /**
1692          * Convert into a list of string being concatenated
1693          * @param array $stringList strings that need to be joined together by the SQL engine
1694          * @return string joined by the concatenation operator
1695          */
1696         public function buildConcat( $stringList ) {
1697                 // || is equivalent to CONCAT
1698                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1699                 return implode( ' || ', $stringList );
1700         }
1701
1702         /**
1703          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1704          * @param string $column name of timestamp column
1705          * @return string SQL code
1706          */
1707         public function extractUnixEpoch( $column ) {
1708                 // TODO
1709                 // see SpecialAncientpages
1710         }
1711
1712         ######################################
1713         # Prepared statements
1714         ######################################
1715
1716         /**
1717          * Intended to be compatible with the PEAR::DB wrapper functions.
1718          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1719          *
1720          * ? = scalar value, quoted as necessary
1721          * ! = raw SQL bit (a function for instance)
1722          * & = filename; reads the file and inserts as a blob
1723          *     (we don't use this though...)
1724          * @param string $sql SQL statement with appropriate markers
1725          * @return resource a prepared DB2 SQL statement
1726          */
1727         public function prepare( $sql, $func = 'DB2::prepare' ) {
1728                 $stmt = db2_prepare($this->mConn, $sql, $this->mStmtOptions);
1729                 return $stmt;
1730         }
1731
1732         /**
1733          * Frees resources associated with a prepared statement
1734          * @return bool success or failure
1735          */
1736         public function freePrepared( $prepared ) {
1737                 return db2_free_stmt($prepared);
1738         }
1739
1740         /**
1741          * Execute a prepared query with the various arguments
1742          * @param       string          $prepared       the prepared sql
1743          * @param       mixed           $args           Either an array here, or put scalars as varargs
1744          * @return      resource                                Results object
1745          */
1746         public function execute( $prepared, $args = null ) {
1747                 if( !is_array( $args ) ) {
1748                         # Pull the var args
1749                         $args = func_get_args();
1750                         array_shift( $args );
1751                 }
1752                 $res = db2_execute($prepared, $args);
1753                 return $res;
1754         }
1755
1756         /**
1757          * Prepare & execute an SQL statement, quoting and inserting arguments
1758          * in the appropriate places.
1759          * @param $query String
1760          * @param $args ...
1761          */
1762         public function safeQuery( $query, $args = null ) {
1763                 // copied verbatim from Database.php
1764                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1765                 if( !is_array( $args ) ) {
1766                         # Pull the var args
1767                         $args = func_get_args();
1768                         array_shift( $args );
1769                 }
1770                 $retval = $this->execute( $prepared, $args );
1771                 $this->freePrepared( $prepared );
1772                 return $retval;
1773         }
1774
1775         /**
1776          * For faking prepared SQL statements on DBs that don't support
1777          * it directly.
1778          * @param       resource        $preparedQuery  String: a 'preparable' SQL statement
1779          * @param       array           $args                   Array of arguments to fill it with
1780          * @return      string                                          executable statement
1781          */
1782         public function fillPrepared( $preparedQuery, $args ) {
1783                 reset( $args );
1784                 $this->preparedArgs =& $args;
1785
1786                 foreach ($args as $i => $arg) {
1787                         db2_bind_param($preparedQuery, $i+1, $args[$i]);
1788                 }
1789
1790                 return $preparedQuery;
1791         }
1792
1793         /**
1794          * Switches module between regular and install modes
1795          */
1796         public function setMode($mode) {
1797                 $old =  $this->mMode;
1798                 $this->mMode = $mode;
1799                 return $old;
1800         }
1801
1802         /**
1803          * Bitwise negation of a column or value in SQL
1804          * Same as (~field) in C
1805          * @param       string  $field
1806          * @return      string
1807          */
1808         function bitNot($field) {
1809                 //expecting bit-fields smaller than 4bytes
1810                 return 'BITNOT('.$bitField.')';
1811         }
1812
1813         /**
1814          * Bitwise AND of two columns or values in SQL
1815          * Same as (fieldLeft & fieldRight) in C
1816          * @param       string  $fieldLeft
1817          * @param       string  $fieldRight
1818          * @return      string
1819          */
1820         function bitAnd($fieldLeft, $fieldRight) {
1821                 return 'BITAND('.$fieldLeft.', '.$fieldRight.')';
1822         }
1823
1824         /**
1825          * Bitwise OR of two columns or values in SQL
1826          * Same as (fieldLeft | fieldRight) in C
1827          * @param       string  $fieldLeft
1828          * @param       string  $fieldRight
1829          * @return      string
1830          */
1831         function bitOr($fieldLeft, $fieldRight) {
1832                 return 'BITOR('.$fieldLeft.', '.$fieldRight.')';
1833         }
1834 }