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