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