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
   5  * and other specific information.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  * @ingroup Database
  24  * @author leo.petr+mediawiki@gmail.com
  25  */
  26
  27 /**
  28  * This represents a column in a DB2 database
  29  * @ingroup Database
  30  */
  31 class IBM_DB2Field implements Field {
  32         private $name = '';
  33         private $tablename = '';
  34         private $type = '';
  35         private $nullable = false;
  36         private $max_length = 0;
  37
  38         /**
  39          * Builder method for the class
  40          * @param $db DatabaseIbm_db2: Database interface
  41          * @param $table String: table name
  42          * @param $field String: column name
  43          * @return IBM_DB2Field
  44          */
  45         static function fromText( $db, $table, $field ) {
  46                 global $wgDBmwschema;
  47
  48                 $q = <<<SQL
  49 SELECT
  50 lcase( coltype ) AS typname,
  51 nulls AS attnotnull, length AS attlen
  52 FROM sysibm.syscolumns
  53 WHERE tbcreator=%s AND tbname=%s AND name=%s;
  54 SQL;
  55                 $res = $db->query(
  56                         sprintf( $q,
  57                                 $db->addQuotes( $wgDBmwschema ),
  58                                 $db->addQuotes( $table ),
  59                                 $db->addQuotes( $field )
  60                         )
  61                 );
  62                 $row = $db->fetchObject( $res );
  63                 if ( !$row ) {
  64                         return null;
  65                 }
  66                 $n = new IBM_DB2Field;
  67                 $n->type = $row->typname;
  68                 $n->nullable = ( $row->attnotnull == 'N' );
  69                 $n->name = $field;
  70                 $n->tablename = $table;
  71                 $n->max_length = $row->attlen;
  72                 return $n;
  73         }
  74         /**
  75          * Get column name
  76          * @return string column name
  77          */
  78         function name() { return $this->name; }
  79         /**
  80          * Get table name
  81          * @return string table name
  82          */
  83         function tableName() { return $this->tablename; }
  84         /**
  85          * Get column type
  86          * @return string column type
  87          */
  88         function type() { return $this->type; }
  89         /**
  90          * Can column be null?
  91          * @return bool true or false
  92          */
  93         function isNullable() { return $this->nullable; }
  94         /**
  95          * How much can you fit in the column per row?
  96          * @return int length
  97          */
  98         function maxLength() { return $this->max_length; }
  99 }
 100
 101 /**
 102  * Wrapper around binary large objects
 103  * @ingroup Database
 104  */
 105 class IBM_DB2Blob {
 106         private $mData;
 107
 108         public function __construct( $data ) {
 109                 $this->mData = $data;
 110         }
 111
 112         public function getData() {
 113                 return $this->mData;
 114         }
 115
 116         public function __toString() {
 117                 return $this->mData;
 118         }
 119 }
 120
 121 /**
 122  * Wrapper to address lack of certain operations in the DB2 driver
 123  *  ( seek, num_rows )
 124  * @ingroup Database
 125  * @since 1.19
 126  */
 127 class IBM_DB2Result{
 128         private $db;
 129         private $result;
 130         private $num_rows;
 131         private $current_pos;
 132         private $columns = array();
 133         private $sql;
 134
 135         private $resultSet = array();
 136         private $loadedLines = 0;
 137
 138         /**
 139          * Construct and initialize a wrapper for DB2 query results
 140          * @param $db DatabaseBase
 141          * @param $result Object
 142          * @param $num_rows Integer
 143          * @param $sql String
 144          * @param $columns Array
 145          */
 146         public function __construct( $db, $result, $num_rows, $sql, $columns ){
 147                 $this->db = $db;
 148
 149                 if( $result instanceof ResultWrapper ){
 150                         $this->result = $result->result;
 151                 }
 152                 else{
 153                         $this->result = $result;
 154                 }
 155
 156                 $this->num_rows = $num_rows;
 157                 $this->current_pos = 0;
 158                 if ( $this->num_rows > 0 ) {
 159                         // Make a lower-case list of the column names
 160                         // By default, DB2 column names are capitalized
 161                         //  while MySQL column names are lowercase
 162
 163                         // Is there a reasonable maximum value for $i?
 164                         // Setting to 2048 to prevent an infinite loop
 165                         for( $i = 0; $i < 2048; $i++ ) {
 166                                 $name = db2_field_name( $this->result, $i );
 167                                 if ( $name != false ) {
 168                                         continue;
 169                                 }
 170                                 else {
 171                                         return false;
 172                                 }
 173
 174                                 $this->columns[$i] = strtolower( $name );
 175                         }
 176                 }
 177
 178                 $this->sql = $sql;
 179         }
 180
 181         /**
 182          * Unwrap the DB2 query results
 183          * @return mixed Object on success, false on failure
 184          */
 185         public function getResult() {
 186                 if ( $this->result ) {
 187                         return $this->result;
 188                 }
 189                 else return false;
 190         }
 191
 192         /**
 193          * Get the number of rows in the result set
 194          * @return integer
 195          */
 196         public function getNum_rows() {
 197                 return $this->num_rows;
 198         }
 199
 200         /**
 201          * Return a row from the result set in object format
 202          * @return mixed Object on success, false on failure.
 203          */
 204         public function fetchObject() {
 205                 if ( $this->result
 206                                 && $this->num_rows > 0
 207                                 && $this->current_pos >= 0
 208                                 && $this->current_pos < $this->num_rows )
 209                 {
 210                         $row = $this->fetchRow();
 211                         $ret = new stdClass();
 212
 213                         foreach ( $row as $k => $v ) {
 214                                 $lc = $this->columns[$k];
 215                                 $ret->$lc = $v;
 216                         }
 217                         return $ret;
 218                 }
 219                 return false;
 220         }
 221
 222         /**
 223          * Return a row form the result set in array format
 224          * @return mixed Array on success, false on failure
 225          * @throws DBUnexpectedError
 226          */
 227         public function fetchRow(){
 228                 if ( $this->result
 229                                 && $this->num_rows > 0
 230                                 && $this->current_pos >= 0
 231                                 && $this->current_pos < $this->num_rows )
 232                 {
 233                         if ( $this->loadedLines <= $this->current_pos ) {
 234                                 $row = db2_fetch_array( $this->result );
 235                                 $this->resultSet[$this->loadedLines++] = $row;
 236                                 if ( $this->db->lastErrno() ) {
 237                                         throw new DBUnexpectedError( $this->db, 'Error in fetchRow(): '
 238                                                 . htmlspecialchars( $this->db->lastError() ) );
 239                                 }
 240                         }
 241
 242                         if ( $this->loadedLines > $this->current_pos ){
 243                                 return $this->resultSet[$this->current_pos++];
 244                         }
 245
 246                 }
 247                 return false;
 248         }
 249
 250         /**
 251          * Free a DB2 result object
 252          * @throws DBUnexpectedError
 253          */
 254         public function freeResult(){
 255                 unset( $this->resultSet );
 256                 if ( !@db2_free_result( $this->result ) ) {
 257                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
 258                 }
 259         }
 260 }
 261
 262 /**
 263  * Primary database interface
 264  * @ingroup Database
 265  */
 266 class DatabaseIbm_db2 extends DatabaseBase {
 267         /*
 268          * Inherited members
 269         protected $mLastQuery = '';
 270         protected $mPHPError = false;
 271
 272         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 273         protected $mOpened = false;
 274
 275         protected $mTablePrefix;
 276         protected $mFlags;
 277         protected $mTrxLevel = 0;
 278         protected $mErrorCount = 0;
 279         protected $mLBInfo = array();
 280         protected $mFakeSlaveLag = null, $mFakeMaster = false;
 281          *
 282          */
 283
 284         /** Database server port */
 285         protected $mPort = null;
 286         /** Schema for tables, stored procedures, triggers */
 287         protected $mSchema = null;
 288         /** Whether the schema has been applied in this session */
 289         protected $mSchemaSet = false;
 290         /** Result of last query */
 291         protected $mLastResult = null;
 292         /** Number of rows affected by last INSERT/UPDATE/DELETE */
 293         protected $mAffectedRows = null;
 294         /** Number of rows returned by last SELECT */
 295         protected $mNumRows = null;
 296         /** Current row number on the cursor of the last SELECT */
 297         protected $currentRow = 0;
 298
 299         /** Connection config options - see constructor */
 300         public $mConnOptions = array();
 301         /** Statement config options -- see constructor */
 302         public $mStmtOptions = array();
 303
 304         /** Default schema */
 305         const USE_GLOBAL = 'get from global';
 306
 307         /** Option that applies to nothing */
 308         const NONE_OPTION = 0x00;
 309         /** Option that applies to connection objects */
 310         const CONN_OPTION = 0x01;
 311         /** Option that applies to statement objects */
 312         const STMT_OPTION = 0x02;
 313
 314         /** Regular operation mode -- minimal debug messages */
 315         const REGULAR_MODE = 'regular';
 316         /** Installation mode -- lots of debug messages */
 317         const INSTALL_MODE = 'install';
 318
 319         /** Controls the level of debug message output */
 320         protected $mMode = self::REGULAR_MODE;
 321
 322         /** Last sequence value used for a primary key */
 323         protected $mInsertId = null;
 324
 325         ######################################
 326         # Getters and Setters
 327         ######################################
 328
 329         /**
 330          * Returns true if this database supports (and uses) cascading deletes
 331          * @return bool
 332          */
 333         function cascadingDeletes() {
 334                 return true;
 335         }
 336
 337         /**
 338          * Returns true if this database supports (and uses) triggers (e.g. on the
 339          *  page table)
 340          * @return bool
 341          */
 342         function cleanupTriggers() {
 343                 return true;
 344         }
 345
 346         /**
 347          * Returns true if this database is strict about what can be put into an
 348          *  IP field.
 349          * Specifically, it uses a NULL value instead of an empty string.
 350          * @return bool
 351          */
 352         function strictIPs() {
 353                 return true;
 354         }
 355
 356         /**
 357          * Returns true if this database uses timestamps rather than integers
 358          * @return bool
 359          */
 360         function realTimestamps() {
 361                 return true;
 362         }
 363
 364         /**
 365          * Returns true if this database does an implicit sort when doing GROUP BY
 366          * @return bool
 367          */
 368         function implicitGroupby() {
 369                 return false;
 370         }
 371
 372         /**
 373          * Returns true if this database does an implicit order by when the column
 374          *  has an index
 375          * For example: SELECT page_title FROM page LIMIT 1
 376          * @return bool
 377          */
 378         function implicitOrderby() {
 379                 return false;
 380         }
 381
 382         /**
 383          * Returns true if this database can do a native search on IP columns
 384          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 385          * @return bool
 386          */
 387         function searchableIPs() {
 388                 return true;
 389         }
 390
 391         /**
 392          * Returns true if this database can use functional indexes
 393          * @return bool
 394          */
 395         function functionalIndexes() {
 396                 return true;
 397         }
 398
 399         /**
 400          * Returns a unique string representing the wiki on the server
 401          * @return string
 402          */
 403         public function getWikiID() {
 404                 if( $this->mSchema ) {
 405                         return "{$this->mDBname}-{$this->mSchema}";
 406                 } else {
 407                         return $this->mDBname;
 408                 }
 409         }
 410
 411         /**
 412          * Returns the database software identifieir
 413          * @return string
 414          */
 415         public function getType() {
 416                 return 'ibm_db2';
 417         }
 418
 419         /**
 420          * Returns the database connection object
 421          * @return Object
 422          */
 423         public function getDb(){
 424                 return $this->mConn;
 425         }
 426
 427         /**
 428          *
 429          * @param $server String: hostname of database server
 430          * @param $user String: username
 431          * @param $password String: password
 432          * @param $dbName String: database name on the server
 433          * @param $flags Integer: database behaviour flags (optional, unused)
 434          * @param $schema String
 435          */
 436         public function __construct( $server = false, $user = false,
 437                                                         $password = false,
 438                                                         $dbName = false, $flags = 0,
 439                                                         $schema = self::USE_GLOBAL )
 440         {
 441                 global $wgDBmwschema;
 442
 443                 if ( $schema == self::USE_GLOBAL ) {
 444                         $this->mSchema = $wgDBmwschema;
 445                 } else {
 446                         $this->mSchema = $schema;
 447                 }
 448
 449                 // configure the connection and statement objects
 450                 $this->setDB2Option( 'db2_attr_case', 'DB2_CASE_LOWER',
 451                         self::CONN_OPTION | self::STMT_OPTION );
 452                 $this->setDB2Option( 'deferred_prepare', 'DB2_DEFERRED_PREPARE_ON',
 453                         self::STMT_OPTION );
 454                 $this->setDB2Option( 'rowcount', 'DB2_ROWCOUNT_PREFETCH_ON',
 455                         self::STMT_OPTION );
 456                 parent::__construct( $server, $user, $password, $dbName, DBO_TRX | $flags );
 457         }
 458
 459         /**
 460          * Enables options only if the ibm_db2 extension version supports them
 461          * @param $name String: name of the option in the options array
 462          * @param $const String: name of the constant holding the right option value
 463          * @param $type Integer: whether this is a Connection or Statement otion
 464          */
 465         private function setDB2Option( $name, $const, $type ) {
 466                 if ( defined( $const ) ) {
 467                         if ( $type & self::CONN_OPTION ) {
 468                                 $this->mConnOptions[$name] = constant( $const );
 469                         }
 470                         if ( $type & self::STMT_OPTION ) {
 471                                 $this->mStmtOptions[$name] = constant( $const );
 472                         }
 473                 } else {
 474                         $this->installPrint(
 475                                 "$const is not defined. ibm_db2 version is likely too low." );
 476                 }
 477         }
 478
 479         /**
 480          * Outputs debug information in the appropriate place
 481          * @param $string String: the relevant debug message
 482          */
 483         private function installPrint( $string ) {
 484                 wfDebug( "$string\n" );
 485                 if ( $this->mMode == self::INSTALL_MODE ) {
 486                         print "<li><pre>$string</pre></li>";
 487                         flush();
 488                 }
 489         }
 490
 491         /**
 492          * Opens a database connection and returns it
 493          * Closes any existing connection
 494          *
 495          * @param $server String: hostname
 496          * @param $user String
 497          * @param $password String
 498          * @param $dbName String: database name
 499          * @throws DBConnectionError
 500          * @return DatabaseBase a fresh connection
 501          */
 502         public function open( $server, $user, $password, $dbName ) {
 503                 wfProfileIn( __METHOD__ );
 504
 505                 # Load IBM DB2 driver if missing
 506                 wfDl( 'ibm_db2' );
 507
 508                 # Test for IBM DB2 support, to avoid suppressed fatal error
 509                 if ( !function_exists( 'db2_connect' ) ) {
 510                         throw new DBConnectionError( $this, "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?" );
 511                 }
 512
 513                 global $wgDBport;
 514
 515                 // Close existing connection
 516                 $this->close();
 517                 // Cache conn info
 518                 $this->mServer = $server;
 519                 $this->mPort = $port = $wgDBport;
 520                 $this->mUser = $user;
 521                 $this->mPassword = $password;
 522                 $this->mDBname = $dbName;
 523
 524                 $this->openUncataloged( $dbName, $user, $password, $server, $port );
 525
 526                 if ( !$this->mConn ) {
 527                         $this->installPrint( "DB connection error\n" );
 528                         $this->installPrint(
 529                                 "Server: $server, Database: $dbName, User: $user, Password: "
 530                                 . substr( $password, 0, 3 ) . "...\n" );
 531                         $this->installPrint( $this->lastError() . "\n" );
 532                         wfProfileOut( __METHOD__ );
 533                         wfDebug( "DB connection error\n" );
 534                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 535                         wfDebug( $this->lastError() . "\n" );
 536                         throw new DBConnectionError( $this, $this->lastError() );
 537                 }
 538
 539                 // Some MediaWiki code is still transaction-less (?).
 540                 // The strategy is to keep AutoCommit on for that code
 541                 //  but switch it off whenever a transaction is begun.
 542                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 543
 544                 $this->mOpened = true;
 545                 $this->applySchema();
 546
 547                 wfProfileOut( __METHOD__ );
 548                 return $this->mConn;
 549         }
 550
 551         /**
 552          * Opens a cataloged database connection, sets mConn
 553          */
 554         protected function openCataloged( $dbName, $user, $password ) {
 555                 wfSuppressWarnings();
 556                 $this->mConn = db2_pconnect( $dbName, $user, $password );
 557                 wfRestoreWarnings();
 558         }
 559
 560         /**
 561          * Opens an uncataloged database connection, sets mConn
 562          */
 563         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 564         {
 565                 $dsn = "DRIVER={IBM DB2 ODBC DRIVER};DATABASE=$dbName;CHARSET=UTF-8;HOSTNAME=$server;PORT=$port;PROTOCOL=TCPIP;UID=$user;PWD=$password;";
 566                 wfSuppressWarnings();
 567                 $this->mConn = db2_pconnect( $dsn, "", "", array() );
 568                 wfRestoreWarnings();
 569         }
 570
 571         /**
 572          * Closes a database connection, if it is open
 573          * Returns success, true if already closed
 574          * @return bool
 575          */
 576         protected function closeConnection() {
 577                 return db2_close( $this->mConn );
 578         }
 579
 580         /**
 581          * Retrieves the most current database error
 582          * Forces a database rollback
 583          * @return bool|string
 584          */
 585         public function lastError() {
 586                 $connerr = db2_conn_errormsg();
 587                 if ( $connerr ) {
 588                         //$this->rollback( __METHOD__ );
 589                         return $connerr;
 590                 }
 591                 $stmterr = db2_stmt_errormsg();
 592                 if ( $stmterr ) {
 593                         //$this->rollback( __METHOD__ );
 594                         return $stmterr;
 595                 }
 596
 597                 return false;
 598         }
 599
 600         /**
 601          * Get the last error number
 602          * Return 0 if no error
 603          * @return integer
 604          */
 605         public function lastErrno() {
 606                 $connerr = db2_conn_error();
 607                 if ( $connerr ) {
 608                         return $connerr;
 609                 }
 610                 $stmterr = db2_stmt_error();
 611                 if ( $stmterr ) {
 612                         return $stmterr;
 613                 }
 614                 return 0;
 615         }
 616
 617         /**
 618          * Is a database connection open?
 619          * @return
 620          */
 621         public function isOpen() { return $this->mOpened; }
 622
 623         /**
 624          * The DBMS-dependent part of query()
 625          * @param  $sql String: SQL query.
 626          * @throws DBUnexpectedError
 627          * @return object Result object for fetch functions or false on failure
 628          */
 629         protected function doQuery( $sql ) {
 630                 $this->applySchema();
 631
 632                 // Needed to handle any UTF-8 encoding issues in the raw sql
 633                 // Note that we fully support prepared statements for DB2
 634                 // prepare() and execute() should be used instead of doQuery() whenever possible
 635                 $sql = utf8_decode( $sql );
 636
 637                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 638                 if( $ret == false ) {
 639                         $error = db2_stmt_errormsg();
 640
 641                         $this->installPrint( "<pre>$sql</pre>" );
 642                         $this->installPrint( $error );
 643                         throw new DBUnexpectedError( $this, 'SQL error: '
 644                                 . htmlspecialchars( $error ) );
 645                 }
 646                 $this->mLastResult = $ret;
 647                 $this->mAffectedRows = null; // Not calculated until asked for
 648                 return $ret;
 649         }
 650
 651         /**
 652          * @return string Version information from the database
 653          */
 654         public function getServerVersion() {
 655                 $info = db2_server_info( $this->mConn );
 656                 return $info->DBMS_VER;
 657         }
 658
 659         /**
 660          * Queries whether a given table exists
 661          * @return boolean
 662          */
 663         public function tableExists( $table, $fname = __METHOD__ ) {
 664                 $schema = $this->mSchema;
 665
 666                 $sql = "SELECT COUNT( * ) FROM SYSIBM.SYSTABLES ST WHERE ST.NAME = '" .
 667                         strtoupper( $table ) .
 668                         "' AND ST.CREATOR = '" .
 669                         strtoupper( $schema ) . "'";
 670                 $res = $this->query( $sql );
 671                 if ( !$res ) {
 672                         return false;
 673                 }
 674
 675                 // If the table exists, there should be one of it
 676                 $row = $this->fetchRow( $res );
 677                 $count = $row[0];
 678                 if ( $count == '1' || $count == 1 ) {
 679                         return true;
 680                 }
 681
 682                 return false;
 683         }
 684
 685         /**
 686          * Fetch the next row from the given result object, in object form.
 687          * Fields can be retrieved with $row->fieldname, with fields acting like
 688          * member variables.
 689          *
 690          * @param $res array|ResultWrapper SQL result object as returned from Database::query(), etc.
 691          * @return DB2 row object
 692          * @throws DBUnexpectedError Thrown if the database returns an error
 693          */
 694         public function fetchObject( $res ) {
 695                 if ( $res instanceof ResultWrapper ) {
 696                         $res = $res->result;
 697                 }
 698                 wfSuppressWarnings();
 699                 $row = db2_fetch_object( $res );
 700                 wfRestoreWarnings();
 701                 if( $this->lastErrno() ) {
 702                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): '
 703                                 . htmlspecialchars( $this->lastError() ) );
 704                 }
 705                 return $row;
 706         }
 707
 708         /**
 709          * Fetch the next row from the given result object, in associative array
 710          * form. Fields are retrieved with $row['fieldname'].
 711          *
 712          * @param $res array|ResultWrapper SQL result object as returned from Database::query(), etc.
 713          * @return ResultWrapper row object
 714          * @throws DBUnexpectedError Thrown if the database returns an error
 715          */
 716         public function fetchRow( $res ) {
 717                 if ( $res instanceof ResultWrapper ) {
 718                         $res = $res->result;
 719                 }
 720                 if ( db2_num_rows( $res ) > 0) {
 721                         wfSuppressWarnings();
 722                         $row = db2_fetch_array( $res );
 723                         wfRestoreWarnings();
 724                         if ( $this->lastErrno() ) {
 725                                 throw new DBUnexpectedError( $this, 'Error in fetchRow(): '
 726                                         . htmlspecialchars( $this->lastError() ) );
 727                         }
 728                         return $row;
 729                 }
 730                 return false;
 731         }
 732
 733         /**
 734          * Escapes strings
 735          * Doesn't escape numbers
 736          *
 737          * @param $s String: string to escape
 738          * @return string escaped string
 739          */
 740         public function addQuotes( $s ) {
 741                 //$this->installPrint( "DB2::addQuotes( $s )\n" );
 742                 if ( is_null( $s ) ) {
 743                         return 'NULL';
 744                 } elseif ( $s instanceof Blob ) {
 745                         return "'" . $s->fetch( $s ) . "'";
 746                 } elseif ( $s instanceof IBM_DB2Blob ) {
 747                         return "'" . $this->decodeBlob( $s ) . "'";
 748                 }
 749                 $s = $this->strencode( $s );
 750                 if ( is_numeric( $s ) ) {
 751                         return $s;
 752                 } else {
 753                         return "'$s'";
 754                 }
 755         }
 756
 757         /**
 758          * Verifies that a DB2 column/field type is numeric
 759          *
 760          * @param $type String: DB2 column type
 761          * @return Boolean: true if numeric
 762          */
 763         public function is_numeric_type( $type ) {
 764                 switch ( strtoupper( $type ) ) {
 765                         case 'SMALLINT':
 766                         case 'INTEGER':
 767                         case 'INT':
 768                         case 'BIGINT':
 769                         case 'DECIMAL':
 770                         case 'REAL':
 771                         case 'DOUBLE':
 772                         case 'DECFLOAT':
 773                                 return true;
 774                 }
 775                 return false;
 776         }
 777
 778         /**
 779          * Alias for addQuotes()
 780          * @param $s String: string to escape
 781          * @return string escaped string
 782          */
 783         public function strencode( $s ) {
 784                 // Bloody useless function
 785                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 786                 //  But also necessary
 787                 $s = db2_escape_string( $s );
 788                 // Wide characters are evil -- some of them look like '
 789                 $s = utf8_encode( $s );
 790                 // Fix its stupidity
 791                 $from = array(  "\\\\", "\\'",  '\\n',  '\\t',  '\\"',  '\\r' );
 792                 $to = array(            "\\",           "''",           "\n",           "\t",           '"',            "\r" );
 793                 $s = str_replace( $from, $to, $s ); // DB2 expects '', not \' escaping
 794                 return $s;
 795         }
 796
 797         /**
 798          * Switch into the database schema
 799          */
 800         protected function applySchema() {
 801                 if ( !( $this->mSchemaSet ) ) {
 802                         $this->mSchemaSet = true;
 803                         $this->begin( __METHOD__ );
 804                         $this->doQuery( "SET SCHEMA = $this->mSchema" );
 805                         $this->commit( __METHOD__ );
 806                 }
 807         }
 808
 809         /**
 810          * Start a transaction (mandatory)
 811          */
 812         protected function doBegin( $fname = 'DatabaseIbm_db2::begin' ) {
 813                 // BEGIN is implicit for DB2
 814                 // However, it requires that AutoCommit be off.
 815
 816                 // Some MediaWiki code is still transaction-less (?).
 817                 // The strategy is to keep AutoCommit on for that code
 818                 //  but switch it off whenever a transaction is begun.
 819                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_OFF );
 820
 821                 $this->mTrxLevel = 1;
 822         }
 823
 824         /**
 825          * End a transaction
 826          * Must have a preceding begin()
 827          */
 828         protected function doCommit( $fname = 'DatabaseIbm_db2::commit' ) {
 829                 db2_commit( $this->mConn );
 830
 831                 // Some MediaWiki code is still transaction-less (?).
 832                 // The strategy is to keep AutoCommit on for that code
 833                 //  but switch it off whenever a transaction is begun.
 834                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 835
 836                 $this->mTrxLevel = 0;
 837         }
 838
 839         /**
 840          * Cancel a transaction
 841          */
 842         protected function doRollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 843                 db2_rollback( $this->mConn );
 844                 // turn auto-commit back on
 845                 // not sure if this is appropriate
 846                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 847                 $this->mTrxLevel = 0;
 848         }
 849
 850         /**
 851          * Makes an encoded list of strings from an array
 852          * $mode:
 853          *   LIST_COMMA         - comma separated, no field names
 854          *   LIST_AND           - ANDed WHERE clause (without the WHERE)
 855          *   LIST_OR            - ORed WHERE clause (without the WHERE)
 856          *   LIST_SET           - comma separated with field names, like a SET clause
 857          *   LIST_NAMES         - comma separated field names
 858          *   LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 859          * @param array $a
 860          * @param int $mode
 861          * @throws DBUnexpectedError
 862          * @return string
 863          */
 864         function makeList( $a, $mode = LIST_COMMA ) {
 865                 if ( !is_array( $a ) ) {
 866                         throw new DBUnexpectedError( $this,
 867                                 'DatabaseIbm_db2::makeList called with incorrect parameters' );
 868                 }
 869
 870                 // if this is for a prepared UPDATE statement
 871                 // (this should be promoted to the parent class
 872                 //  once other databases use prepared statements)
 873                 if ( $mode == LIST_SET_PREPARED ) {
 874                         $first = true;
 875                         $list = '';
 876                         foreach ( $a as $field => $value ) {
 877                                 if ( !$first ) {
 878                                         $list .= ", $field = ?";
 879                                 } else {
 880                                         $list .= "$field = ?";
 881                                         $first = false;
 882                                 }
 883                         }
 884                         $list .= '';
 885
 886                         return $list;
 887                 }
 888
 889                 // otherwise, call the usual function
 890                 return parent::makeList( $a, $mode );
 891         }
 892
 893         /**
 894          * Construct a LIMIT query with optional offset
 895          * This is used for query pages
 896          *
 897          * @param $sql string SQL query we will append the limit too
 898          * @param $limit integer the SQL limit
 899          * @param bool|int $offset SQL offset (default false)
 900          * @throws DBUnexpectedError
 901          * @return string
 902          */
 903         public function limitResult( $sql, $limit, $offset=false ) {
 904                 if( !is_numeric( $limit ) ) {
 905                         throw new DBUnexpectedError( $this,
 906                                 "Invalid non-numeric limit passed to limitResult()\n" );
 907                 }
 908                 if( $offset ) {
 909                         if ( stripos( $sql, 'where' ) === false ) {
 910                                 return "$sql AND ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 911                         } else {
 912                                 return "$sql WHERE ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 913                         }
 914                 }
 915                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 916         }
 917
 918         /**
 919          * Handle reserved keyword replacement in table names
 920          *
 921          * @param $name Object
 922          * @param $format String Ignored parameter Default 'quoted'Boolean
 923          * @return String
 924          */
 925         public function tableName( $name, $format = 'quoted' ) {
 926                 // we want maximum compatibility with MySQL schema
 927                 return $name;
 928         }
 929
 930         /**
 931          * Generates a timestamp in an insertable format
 932          *
 933          * @param $ts string timestamp
 934          * @return String: timestamp value
 935          */
 936         public function timestamp( $ts = 0 ) {
 937                 // TS_MW cannot be easily distinguished from an integer
 938                 return wfTimestamp( TS_DB2, $ts );
 939         }
 940
 941         /**
 942          * Return the next in a sequence, save the value for retrieval via insertId()
 943          * @param $seqName String: name of a defined sequence in the database
 944          * @return int next value in that sequence
 945          */
 946         public function nextSequenceValue( $seqName ) {
 947                 // Not using sequences in the primary schema to allow for easier migration
 948                 //  from MySQL
 949                 // Emulating MySQL behaviour of using NULL to signal that sequences
 950                 // aren't used
 951                 /*
 952                 $safeseq = preg_replace( "/'/", "''", $seqName );
 953                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 954                 $row = $this->fetchRow( $res );
 955                 $this->mInsertId = $row[0];
 956                 return $this->mInsertId;
 957                 */
 958                 return null;
 959         }
 960
 961         /**
 962          * This must be called after nextSequenceVal
 963          * @return int Last sequence value used as a primary key
 964          */
 965         public function insertId() {
 966                 return $this->mInsertId;
 967         }
 968
 969         /**
 970          * Updates the mInsertId property with the value of the last insert
 971          *  into a generated column
 972          *
 973          * @param $table      String: sanitized table name
 974          * @param $primaryKey Mixed: string name of the primary key
 975          * @param $stmt       Resource: prepared statement resource
 976          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
 977          */
 978         private function calcInsertId( $table, $primaryKey, $stmt ) {
 979                 if ( $primaryKey ) {
 980                         $this->mInsertId = db2_last_insert_id( $this->mConn );
 981                 }
 982         }
 983
 984         /**
 985          * INSERT wrapper, inserts an array into a table
 986          *
 987          * $args may be a single associative array, or an array of arrays
 988          *  with numeric keys, for multi-row insert
 989          *
 990          * @param $table   String: Name of the table to insert to.
 991          * @param $args    Array: Items to insert into the table.
 992          * @param $fname   String: Name of the function, for profiling
 993          * @param $options String or Array. Valid options: IGNORE
 994          *
 995          * @return bool Success of insert operation. IGNORE always returns true.
 996          */
 997         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert',
 998                 $options = array() )
 999         {
1000                 if ( !count( $args ) ) {
1001                         return true;
1002                 }
1003                 // get database-specific table name (not used)
1004                 $table = $this->tableName( $table );
1005                 // format options as an array
1006                 $options = IBM_DB2Helper::makeArray( $options );
1007                 // format args as an array of arrays
1008                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
1009                         $args = array( $args );
1010                 }
1011
1012                 // prevent insertion of NULL into primary key columns
1013                 list( $args, $primaryKeys ) = $this->removeNullPrimaryKeys( $table, $args );
1014                 // if there's only one primary key
1015                 // we'll be able to read its value after insertion
1016                 $primaryKey = false;
1017                 if ( count( $primaryKeys ) == 1 ) {
1018                         $primaryKey = $primaryKeys[0];
1019                 }
1020
1021                 // get column names
1022                 $keys = array_keys( $args[0] );
1023                 $key_count = count( $keys );
1024
1025                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
1026                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
1027
1028                 // assume success
1029                 $res = true;
1030                 // If we are not in a transaction, we need to be for savepoint trickery
1031                 if ( !$this->mTrxLevel ) {
1032                         $this->begin( __METHOD__ );
1033                 }
1034
1035                 $sql = "INSERT INTO $table ( " . implode( ',', $keys ) . ' ) VALUES ';
1036                 if ( $key_count == 1 ) {
1037                         $sql .= '( ? )';
1038                 } else {
1039                         $sql .= '( ?' . str_repeat( ',?', $key_count-1 ) . ' )';
1040                 }
1041                 $this->installPrint( "Preparing the following SQL:" );
1042                 $this->installPrint( "$sql" );
1043                 $this->installPrint( print_r( $args, true ));
1044                 $stmt = $this->prepare( $sql );
1045
1046                 // start a transaction/enter transaction mode
1047                 $this->begin( __METHOD__ );
1048
1049                 if ( !$ignore ) {
1050                         //$first = true;
1051                         foreach ( $args as $row ) {
1052                                 //$this->installPrint( "Inserting " . print_r( $row, true ));
1053                                 // insert each row into the database
1054                                 $res = $res & $this->execute( $stmt, $row );
1055                                 if ( !$res ) {
1056                                         $this->installPrint( 'Last error:' );
1057                                         $this->installPrint( $this->lastError() );
1058                                 }
1059                                 // get the last inserted value into a generated column
1060                                 $this->calcInsertId( $table, $primaryKey, $stmt );
1061                         }
1062                 } else {
1063                         $olde = error_reporting( 0 );
1064                         // For future use, we may want to track the number of actual inserts
1065                         // Right now, insert (all writes) simply return true/false
1066                         $numrowsinserted = 0;
1067
1068                         // always return true
1069                         $res = true;
1070
1071                         foreach ( $args as $row ) {
1072                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
1073                                 db2_exec( $this->mConn, $overhead, $this->mStmtOptions );
1074
1075                                 $res2 = $this->execute( $stmt, $row );
1076
1077                                 if ( !$res2 ) {
1078                                         $this->installPrint( 'Last error:' );
1079                                         $this->installPrint( $this->lastError() );
1080                                 }
1081                                 // get the last inserted value into a generated column
1082                                 $this->calcInsertId( $table, $primaryKey, $stmt );
1083
1084                                 $errNum = $this->lastErrno();
1085                                 if ( $errNum ) {
1086                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore",
1087                                                 $this->mStmtOptions );
1088                                 } else {
1089                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore",
1090                                                 $this->mStmtOptions );
1091                                         $numrowsinserted++;
1092                                 }
1093                         }
1094
1095                         $olde = error_reporting( $olde );
1096                         // Set the affected row count for the whole operation
1097                         $this->mAffectedRows = $numrowsinserted;
1098                 }
1099                 // commit either way
1100                 $this->commit( __METHOD__ );
1101                 $this->freePrepared( $stmt );
1102
1103                 return $res;
1104         }
1105
1106         /**
1107          * Given a table name and a hash of columns with values
1108          * Removes primary key columns from the hash where the value is NULL
1109          *
1110          * @param $table String: name of the table
1111          * @param $args Array of hashes of column names with values
1112          * @return Array: tuple( filtered array of columns, array of primary keys )
1113          */
1114         private function removeNullPrimaryKeys( $table, $args ) {
1115                 $schema = $this->mSchema;
1116
1117                 // find out the primary keys
1118                 $keyres = $this->doQuery( "SELECT NAME FROM SYSIBM.SYSCOLUMNS WHERE TBNAME = '"
1119                   . strtoupper( $table )
1120                   . "' AND TBCREATOR = '"
1121                   . strtoupper( $schema )
1122                   . "' AND KEYSEQ > 0" );
1123
1124                 $keys = array();
1125                 for (
1126                         $row = $this->fetchRow( $keyres );
1127                         $row != null;
1128                         $row = $this->fetchRow( $keyres )
1129                 )
1130                 {
1131                         $keys[] = strtolower( $row[0] );
1132                 }
1133                 // remove primary keys
1134                 foreach ( $args as $ai => $row ) {
1135                         foreach ( $keys as $key ) {
1136                                 if ( $row[$key] == null ) {
1137                                         unset( $row[$key] );
1138                                 }
1139                         }
1140                         $args[$ai] = $row;
1141                 }
1142                 // return modified hash
1143                 return array( $args, $keys );
1144         }
1145
1146         /**
1147          * UPDATE wrapper, takes a condition array and a SET array
1148          *
1149          * @param $table  String: The table to UPDATE
1150          * @param $values array An array of values to SET
1151          * @param $conds  array An array of conditions ( WHERE ). Use '*' to update all rows.
1152          * @param $fname  String: The Class::Function calling this function
1153          *                ( for the log )
1154          * @param $options array An array of UPDATE options, can be one or
1155          *                 more of IGNORE, LOW_PRIORITY
1156          * @return Boolean
1157          */
1158         public function update( $table, $values, $conds, $fname = 'DatabaseIbm_db2::update',
1159                 $options = array() )
1160         {
1161                 $table = $this->tableName( $table );
1162                 $opts = $this->makeUpdateOptions( $options );
1163                 $sql = "UPDATE $opts $table SET "
1164                         . $this->makeList( $values, LIST_SET_PREPARED );
1165                 if ( $conds != '*' ) {
1166                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1167                 }
1168                 $stmt = $this->prepare( $sql );
1169                 $this->installPrint( 'UPDATE: ' . print_r( $values, true ) );
1170                 // assuming for now that an array with string keys will work
1171                 // if not, convert to simple array first
1172                 $result = $this->execute( $stmt, $values );
1173                 $this->freePrepared( $stmt );
1174
1175                 return $result;
1176         }
1177
1178         /**
1179          * DELETE query wrapper
1180          *
1181          * Use $conds == "*" to delete all rows
1182          * @param array $table
1183          * @param array|string $conds
1184          * @param string $fname
1185          * @throws DBUnexpectedError
1186          * @return bool|\ResultWrapper
1187          */
1188         public function delete( $table, $conds, $fname = 'DatabaseIbm_db2::delete' ) {
1189                 if ( !$conds ) {
1190                         throw new DBUnexpectedError( $this,
1191                                 'DatabaseIbm_db2::delete() called with no conditions' );
1192                 }
1193                 $table = $this->tableName( $table );
1194                 $sql = "DELETE FROM $table";
1195                 if ( $conds != '*' ) {
1196                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1197                 }
1198                 $result = $this->query( $sql, $fname );
1199
1200                 return $result;
1201         }
1202
1203         /**
1204          * Returns the number of rows affected by the last query or 0
1205          * @return Integer: the number of rows affected by the last query
1206          */
1207         public function affectedRows() {
1208                 if ( !is_null( $this->mAffectedRows ) ) {
1209                         // Forced result for simulated queries
1210                         return $this->mAffectedRows;
1211                 }
1212                 if( empty( $this->mLastResult ) ) {
1213                         return 0;
1214                 }
1215                 return db2_num_rows( $this->mLastResult );
1216         }
1217
1218         /**
1219          * Returns the number of rows in the result set
1220          * Has to be called right after the corresponding select query
1221          * @param $res Object result set
1222          * @return Integer: number of rows
1223          */
1224         public function numRows( $res ) {
1225                 if ( $res instanceof ResultWrapper ) {
1226                         $res = $res->result;
1227                 }
1228
1229                 if ( $this->mNumRows ) {
1230                         return $this->mNumRows;
1231                 } else {
1232                         return 0;
1233                 }
1234         }
1235
1236         /**
1237          * Moves the row pointer of the result set
1238          * @param $res Object: result set
1239          * @param $row Integer: row number
1240          * @return bool success or failure
1241          */
1242         public function dataSeek( $res, $row ) {
1243                 if ( $res instanceof ResultWrapper ) {
1244                         return $res = $res->result;
1245                 }
1246                 if ( $res instanceof IBM_DB2Result ) {
1247                         return $res->dataSeek( $row );
1248                 }
1249                 wfDebug( "dataSeek operation in DB2 database\n" );
1250                 return false;
1251         }
1252
1253         ###
1254         # Fix notices in Block.php
1255         ###
1256
1257         /**
1258          * Frees memory associated with a statement resource
1259          * @param $res Object: statement resource to free
1260          * @throws DBUnexpectedError
1261          * @return Boolean success or failure
1262          */
1263         public function freeResult( $res ) {
1264                 if ( $res instanceof ResultWrapper ) {
1265                         $res = $res->result;
1266                 }
1267                 wfSuppressWarnings();
1268                 $ok = db2_free_result( $res );
1269                 wfRestoreWarnings();
1270                 if ( !$ok ) {
1271                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
1272                 }
1273         }
1274
1275         /**
1276          * Returns the number of columns in a resource
1277          * @param $res Object: statement resource
1278          * @return Number of fields/columns in resource
1279          */
1280         public function numFields( $res ) {
1281                 if ( $res instanceof ResultWrapper ) {
1282                         $res = $res->result;
1283                 }
1284                 if ( $res instanceof IBM_DB2Result ) {
1285                         $res = $res->getResult();
1286                 }
1287                 return db2_num_fields( $res );
1288         }
1289
1290         /**
1291          * Returns the nth column name
1292          * @param $res Object: statement resource
1293          * @param $n Integer: Index of field or column
1294          * @return String name of nth column
1295          */
1296         public function fieldName( $res, $n ) {
1297                 if ( $res instanceof ResultWrapper ) {
1298                         $res = $res->result;
1299                 }
1300                 if ( $res instanceof IBM_DB2Result ) {
1301                         $res = $res->getResult();
1302                 }
1303                 return db2_field_name( $res, $n );
1304         }
1305
1306         /**
1307          * SELECT wrapper
1308          *
1309          * @param $table   Array or string, table name(s) (prefix auto-added)
1310          * @param $vars    Array or string, field name(s) to be retrieved
1311          * @param $conds   Array or string, condition(s) for WHERE
1312          * @param $fname   String: calling function name (use __METHOD__)
1313          *                 for logs/profiling
1314          * @param $options array Associative array of options
1315          *                 (e.g. array( 'GROUP BY' => 'page_title' )),
1316          *                 see Database::makeSelectOptions code for list of
1317          *                 supported stuff
1318          * @param $join_conds array Associative array of table join conditions (optional)
1319          *                    (e.g. array( 'page' => array('LEFT JOIN',
1320          *                    'page_latest=rev_id') )
1321          * @return Mixed: database result resource for fetch functions or false
1322          *                 on failure
1323          */
1324         public function select( $table, $vars, $conds = '', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1325         {
1326                 $res = parent::select( $table, $vars, $conds, $fname, $options,
1327                         $join_conds );
1328                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
1329
1330                 // We must adjust for offset
1331                 if ( isset( $options['LIMIT'] ) && isset ( $options['OFFSET'] ) ) {
1332                         $limit = $options['LIMIT'];
1333                         $offset = $options['OFFSET'];
1334                 }
1335
1336                 // DB2 does not have a proper num_rows() function yet, so we must emulate
1337                 // DB2 9.5.4 and the corresponding ibm_db2 driver will introduce
1338                 //  a working one
1339                 // TODO: Yay!
1340
1341                 // we want the count
1342                 $vars2 = array( 'count( * ) as num_rows' );
1343                 // respecting just the limit option
1344                 $options2 = array();
1345                 if ( isset( $options['LIMIT'] ) ) {
1346                         $options2['LIMIT'] = $options['LIMIT'];
1347                 }
1348                 // but don't try to emulate for GROUP BY
1349                 if ( isset( $options['GROUP BY'] ) ) {
1350                         return $res;
1351                 }
1352
1353                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2,
1354                         $join_conds );
1355
1356                 $obj = $this->fetchObject( $res2 );
1357                 $this->mNumRows = $obj->num_rows;
1358
1359                 return new ResultWrapper( $this, new IBM_DB2Result( $this, $res, $obj->num_rows, $vars, $sql ) );
1360         }
1361
1362         /**
1363          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1364          * Has limited support for per-column options (colnum => 'DISTINCT')
1365          *
1366          * @private
1367          *
1368          * @param $options array Associative array of options to be turned into
1369          *              an SQL query, valid keys are listed in the function.
1370          * @return Array
1371          */
1372         function makeSelectOptions( $options ) {
1373                 $preLimitTail = $postLimitTail = '';
1374                 $startOpts = '';
1375
1376                 $noKeyOptions = array();
1377                 foreach ( $options as $key => $option ) {
1378                         if ( is_numeric( $key ) ) {
1379                                 $noKeyOptions[$option] = true;
1380                         }
1381                 }
1382
1383                 if ( isset( $options['GROUP BY'] ) ) {
1384                         $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1385                 }
1386                 if ( isset( $options['HAVING'] ) ) {
1387                         $preLimitTail .= " HAVING {$options['HAVING']}";
1388                 }
1389                 if ( isset( $options['ORDER BY'] ) ) {
1390                         $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1391                 }
1392
1393                 if ( isset( $noKeyOptions['DISTINCT'] )
1394                         || isset( $noKeyOptions['DISTINCTROW'] ) )
1395                 {
1396                         $startOpts .= 'DISTINCT';
1397                 }
1398
1399                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1400         }
1401
1402         /**
1403          * Returns link to IBM DB2 free download
1404          * @return String: wikitext of a link to the server software's web site
1405          */
1406         public static function getSoftwareLink() {
1407                 return '[http://www.ibm.com/db2/express/ IBM DB2]';
1408         }
1409
1410         /**
1411          * Get search engine class. All subclasses of this
1412          * need to implement this if they wish to use searching.
1413          *
1414          * @return String
1415          */
1416         public function getSearchEngine() {
1417                 return 'SearchIBM_DB2';
1418         }
1419
1420         /**
1421          * Did the last database access fail because of deadlock?
1422          * @return Boolean
1423          */
1424         public function wasDeadlock() {
1425                 // get SQLSTATE
1426                 $err = $this->lastErrno();
1427                 switch( $err ) {
1428                         // This is literal port of the MySQL logic and may be wrong for DB2
1429                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1430                         case '57011':   // sql0904n, Resource unavailable, no rollback
1431                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1432                         $this->installPrint( "In a deadlock because of SQLSTATE $err" );
1433                         return true;
1434                 }
1435                 return false;
1436         }
1437
1438         /**
1439          * Ping the server and try to reconnect if it there is no connection
1440          * The connection may be closed and reopened while this happens
1441          * @return Boolean: whether the connection exists
1442          */
1443         public function ping() {
1444                 // db2_ping() doesn't exist
1445                 // Emulate
1446                 $this->close();
1447                 $this->openUncataloged( $this->mDBName, $this->mUser,
1448                         $this->mPassword, $this->mServer, $this->mPort );
1449
1450                 return false;
1451         }
1452         ######################################
1453         # Unimplemented and not applicable
1454         ######################################
1455
1456         /**
1457          * Only useful with fake prepare like in base Database class
1458          * @return      string
1459          */
1460         public function fillPreparedArg( $matches ) {
1461                 $this->installPrint( 'Not useful for DB2: fillPreparedArg()' );
1462                 return '';
1463         }
1464
1465         ######################################
1466         # Reflection
1467         ######################################
1468
1469         /**
1470          * Returns information about an index
1471          * If errors are explicitly ignored, returns NULL on failure
1472          * @param $table String: table name
1473          * @param $index String: index name
1474          * @param $fname String: function name for logging and profiling
1475          * @return Object query row in object form
1476          */
1477         public function indexInfo( $table, $index,
1478                 $fname = 'DatabaseIbm_db2::indexExists' )
1479         {
1480                 $table = $this->tableName( $table );
1481                 $sql = <<<SQL
1482 SELECT name as indexname
1483 FROM sysibm.sysindexes si
1484 WHERE si.name='$index' AND si.tbname='$table'
1485 AND sc.tbcreator='$this->mSchema'
1486 SQL;
1487                 $res = $this->query( $sql, $fname );
1488                 if ( !$res ) {
1489                         return null;
1490                 }
1491                 $row = $this->fetchObject( $res );
1492                 if ( $row != null ) {
1493                         return $row;
1494                 } else {
1495                         return false;
1496                 }
1497         }
1498
1499         /**
1500          * Returns an information object on a table column
1501          * @param $table String: table name
1502          * @param $field String: column name
1503          * @return IBM_DB2Field
1504          */
1505         public function fieldInfo( $table, $field ) {
1506                 return IBM_DB2Field::fromText( $this, $table, $field );
1507         }
1508
1509         /**
1510          * db2_field_type() wrapper
1511          * @param $res Object: result of executed statement
1512          * @param $index Mixed: number or name of the column
1513          * @return String column type
1514          */
1515         public function fieldType( $res, $index ) {
1516                 if ( $res instanceof ResultWrapper ) {
1517                         $res = $res->result;
1518                 }
1519                 if ( $res instanceof IBM_DB2Result ) {
1520                         $res = $res->getResult();
1521                 }
1522                 return db2_field_type( $res, $index );
1523         }
1524
1525         /**
1526          * Verifies that an index was created as unique
1527          * @param $table String: table name
1528          * @param $index String: index name
1529          * @param $fname string function name for profiling
1530          * @return Bool
1531          */
1532         public function indexUnique ( $table, $index,
1533                 $fname = 'DatabaseIbm_db2::indexUnique' )
1534         {
1535                 $table = $this->tableName( $table );
1536                 $sql = <<<SQL
1537 SELECT si.name as indexname
1538 FROM sysibm.sysindexes si
1539 WHERE si.name='$index' AND si.tbname='$table'
1540 AND sc.tbcreator='$this->mSchema'
1541 AND si.uniquerule IN ( 'U', 'P' )
1542 SQL;
1543                 $res = $this->query( $sql, $fname );
1544                 if ( !$res ) {
1545                         return null;
1546                 }
1547                 if ( $this->fetchObject( $res ) ) {
1548                         return true;
1549                 }
1550                 return false;
1551
1552         }
1553
1554         /**
1555          * Returns the size of a text field, or -1 for "unlimited"
1556          * @param $table String: table name
1557          * @param $field String: column name
1558          * @return Integer: length or -1 for unlimited
1559          */
1560         public function textFieldSize( $table, $field ) {
1561                 $table = $this->tableName( $table );
1562                 $sql = <<<SQL
1563 SELECT length as size
1564 FROM sysibm.syscolumns sc
1565 WHERE sc.name='$field' AND sc.tbname='$table'
1566 AND sc.tbcreator='$this->mSchema'
1567 SQL;
1568                 $res = $this->query( $sql );
1569                 $row = $this->fetchObject( $res );
1570                 $size = $row->size;
1571                 return $size;
1572         }
1573
1574         /**
1575          * Description is left as an exercise for the reader
1576          * @param $b Mixed: data to be encoded
1577          * @return IBM_DB2Blob
1578          */
1579         public function encodeBlob( $b ) {
1580                 return new IBM_DB2Blob( $b );
1581         }
1582
1583         /**
1584          * Description is left as an exercise for the reader
1585          * @param $b IBM_DB2Blob: data to be decoded
1586          * @return mixed
1587          */
1588         public function decodeBlob( $b ) {
1589                 return "$b";
1590         }
1591
1592         /**
1593          * Convert into a list of string being concatenated
1594          * @param $stringList Array: strings that need to be joined together
1595          *                    by the SQL engine
1596          * @return String: joined by the concatenation operator
1597          */
1598         public function buildConcat( $stringList ) {
1599                 // || is equivalent to CONCAT
1600                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1601                 return implode( ' || ', $stringList );
1602         }
1603
1604         /**
1605          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1606          * @param $column String: name of timestamp column
1607          * @return String: SQL code
1608          */
1609         public function extractUnixEpoch( $column ) {
1610                 // TODO
1611                 // see SpecialAncientpages
1612         }
1613
1614         ######################################
1615         # Prepared statements
1616         ######################################
1617
1618         /**
1619          * Intended to be compatible with the PEAR::DB wrapper functions.
1620          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1621          *
1622          * ? = scalar value, quoted as necessary
1623          * ! = raw SQL bit (a function for instance)
1624          * & = filename; reads the file and inserts as a blob
1625          *     (we don't use this though...)
1626          * @param $sql String: SQL statement with appropriate markers
1627          * @param $func String: Name of the function, for profiling
1628          * @return resource a prepared DB2 SQL statement
1629          */
1630         public function prepare( $sql, $func = 'DB2::prepare' ) {
1631                 $stmt = db2_prepare( $this->mConn, $sql, $this->mStmtOptions );
1632                 return $stmt;
1633         }
1634
1635         /**
1636          * Frees resources associated with a prepared statement
1637          * @return Boolean success or failure
1638          */
1639         public function freePrepared( $prepared ) {
1640                 return db2_free_stmt( $prepared );
1641         }
1642
1643         /**
1644          * Execute a prepared query with the various arguments
1645          * @param $prepared String: the prepared sql
1646          * @param $args Mixed: either an array here, or put scalars as varargs
1647          * @return Resource: results object
1648          */
1649         public function execute( $prepared, $args = null ) {
1650                 if( !is_array( $args ) ) {
1651                         # Pull the var args
1652                         $args = func_get_args();
1653                         array_shift( $args );
1654                 }
1655                 $res = db2_execute( $prepared, $args );
1656                 if ( !$res ) {
1657                         $this->installPrint( db2_stmt_errormsg() );
1658                 }
1659                 return $res;
1660         }
1661
1662         /**
1663          * For faking prepared SQL statements on DBs that don't support
1664          * it directly.
1665          * @param $preparedQuery String: a 'preparable' SQL statement
1666          * @param $args Array of arguments to fill it with
1667          * @return String: executable statement
1668          */
1669         public function fillPrepared( $preparedQuery, $args ) {
1670                 reset( $args );
1671                 $this->preparedArgs =& $args;
1672
1673                 foreach ( $args as $i => $arg ) {
1674                         db2_bind_param( $preparedQuery, $i+1, $args[$i] );
1675                 }
1676
1677                 return $preparedQuery;
1678         }
1679
1680         /**
1681          * Switches module between regular and install modes
1682          * @return string
1683          */
1684         public function setMode( $mode ) {
1685                 $old = $this->mMode;
1686                 $this->mMode = $mode;
1687                 return $old;
1688         }
1689
1690         /**
1691          * Bitwise negation of a column or value in SQL
1692          * Same as (~field) in C
1693          * @param $field String
1694          * @return String
1695          */
1696         function bitNot( $field ) {
1697                 // expecting bit-fields smaller than 4bytes
1698                 return "BITNOT( $field )";
1699         }
1700
1701         /**
1702          * Bitwise AND of two columns or values in SQL
1703          * Same as (fieldLeft & fieldRight) in C
1704          * @param $fieldLeft String
1705          * @param $fieldRight String
1706          * @return String
1707          */
1708         function bitAnd( $fieldLeft, $fieldRight ) {
1709                 return "BITAND( $fieldLeft, $fieldRight )";
1710         }
1711
1712         /**
1713          * Bitwise OR of two columns or values in SQL
1714          * Same as (fieldLeft | fieldRight) in C
1715          * @param $fieldLeft String
1716          * @param $fieldRight String
1717          * @return String
1718          */
1719         function bitOr( $fieldLeft, $fieldRight ) {
1720                 return "BITOR( $fieldLeft, $fieldRight )";
1721         }
1722 }
1723
1724 class IBM_DB2Helper {
1725         public static function makeArray( $maybeArray ) {
1726                 if ( !is_array( $maybeArray ) ) {
1727                         return array( $maybeArray );
1728                 }
1729
1730                 return $maybeArray;
1731         }
1732 }