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          * @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          * @return object Result object for fetch functions or false on failure
 626          */
 627         protected function doQuery( $sql ) {
 628                 $this->applySchema();
 629
 630                 // Needed to handle any UTF-8 encoding issues in the raw sql
 631                 // Note that we fully support prepared statements for DB2
 632                 // prepare() and execute() should be used instead of doQuery() whenever possible
 633                 $sql = utf8_decode( $sql );
 634
 635                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 636                 if( $ret == false ) {
 637                         $error = db2_stmt_errormsg();
 638
 639                         $this->installPrint( "<pre>$sql</pre>" );
 640                         $this->installPrint( $error );
 641                         throw new DBUnexpectedError( $this, 'SQL error: '
 642                                 . htmlspecialchars( $error ) );
 643                 }
 644                 $this->mLastResult = $ret;
 645                 $this->mAffectedRows = null; // Not calculated until asked for
 646                 return $ret;
 647         }
 648
 649         /**
 650          * @return string Version information from the database
 651          */
 652         public function getServerVersion() {
 653                 $info = db2_server_info( $this->mConn );
 654                 return $info->DBMS_VER;
 655         }
 656
 657         /**
 658          * Queries whether a given table exists
 659          * @return boolean
 660          */
 661         public function tableExists( $table, $fname = __METHOD__ ) {
 662                 $schema = $this->mSchema;
 663
 664                 $sql = "SELECT COUNT( * ) FROM SYSIBM.SYSTABLES ST WHERE ST.NAME = '" .
 665                         strtoupper( $table ) .
 666                         "' AND ST.CREATOR = '" .
 667                         strtoupper( $schema ) . "'";
 668                 $res = $this->query( $sql );
 669                 if ( !$res ) {
 670                         return false;
 671                 }
 672
 673                 // If the table exists, there should be one of it
 674                 $row = $this->fetchRow( $res );
 675                 $count = $row[0];
 676                 if ( $count == '1' || $count == 1 ) {
 677                         return true;
 678                 }
 679
 680                 return false;
 681         }
 682
 683         /**
 684          * Fetch the next row from the given result object, in object form.
 685          * Fields can be retrieved with $row->fieldname, with fields acting like
 686          * member variables.
 687          *
 688          * @param $res array|ResultWrapper SQL result object as returned from Database::query(), etc.
 689          * @return DB2 row object
 690          * @throws DBUnexpectedError Thrown if the database returns an error
 691          */
 692         public function fetchObject( $res ) {
 693                 if ( $res instanceof ResultWrapper ) {
 694                         $res = $res->result;
 695                 }
 696                 wfSuppressWarnings();
 697                 $row = db2_fetch_object( $res );
 698                 wfRestoreWarnings();
 699                 if( $this->lastErrno() ) {
 700                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): '
 701                                 . htmlspecialchars( $this->lastError() ) );
 702                 }
 703                 return $row;
 704         }
 705
 706         /**
 707          * Fetch the next row from the given result object, in associative array
 708          * form. Fields are retrieved with $row['fieldname'].
 709          *
 710          * @param $res array|ResultWrapper SQL result object as returned from Database::query(), etc.
 711          * @return ResultWrapper row object
 712          * @throws DBUnexpectedError Thrown if the database returns an error
 713          */
 714         public function fetchRow( $res ) {
 715                 if ( $res instanceof ResultWrapper ) {
 716                         $res = $res->result;
 717                 }
 718                 if ( db2_num_rows( $res ) > 0) {
 719                         wfSuppressWarnings();
 720                         $row = db2_fetch_array( $res );
 721                         wfRestoreWarnings();
 722                         if ( $this->lastErrno() ) {
 723                                 throw new DBUnexpectedError( $this, 'Error in fetchRow(): '
 724                                         . htmlspecialchars( $this->lastError() ) );
 725                         }
 726                         return $row;
 727                 }
 728                 return false;
 729         }
 730
 731         /**
 732          * Escapes strings
 733          * Doesn't escape numbers
 734          *
 735          * @param $s String: string to escape
 736          * @return string escaped string
 737          */
 738         public function addQuotes( $s ) {
 739                 //$this->installPrint( "DB2::addQuotes( $s )\n" );
 740                 if ( is_null( $s ) ) {
 741                         return 'NULL';
 742                 } elseif ( $s instanceof Blob ) {
 743                         return "'" . $s->fetch( $s ) . "'";
 744                 } elseif ( $s instanceof IBM_DB2Blob ) {
 745                         return "'" . $this->decodeBlob( $s ) . "'";
 746                 }
 747                 $s = $this->strencode( $s );
 748                 if ( is_numeric( $s ) ) {
 749                         return $s;
 750                 } else {
 751                         return "'$s'";
 752                 }
 753         }
 754
 755         /**
 756          * Verifies that a DB2 column/field type is numeric
 757          *
 758          * @param $type String: DB2 column type
 759          * @return Boolean: true if numeric
 760          */
 761         public function is_numeric_type( $type ) {
 762                 switch ( strtoupper( $type ) ) {
 763                         case 'SMALLINT':
 764                         case 'INTEGER':
 765                         case 'INT':
 766                         case 'BIGINT':
 767                         case 'DECIMAL':
 768                         case 'REAL':
 769                         case 'DOUBLE':
 770                         case 'DECFLOAT':
 771                                 return true;
 772                 }
 773                 return false;
 774         }
 775
 776         /**
 777          * Alias for addQuotes()
 778          * @param $s String: string to escape
 779          * @return string escaped string
 780          */
 781         public function strencode( $s ) {
 782                 // Bloody useless function
 783                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 784                 //  But also necessary
 785                 $s = db2_escape_string( $s );
 786                 // Wide characters are evil -- some of them look like '
 787                 $s = utf8_encode( $s );
 788                 // Fix its stupidity
 789                 $from = array(  "\\\\", "\\'",  '\\n',  '\\t',  '\\"',  '\\r' );
 790                 $to = array(            "\\",           "''",           "\n",           "\t",           '"',            "\r" );
 791                 $s = str_replace( $from, $to, $s ); // DB2 expects '', not \' escaping
 792                 return $s;
 793         }
 794
 795         /**
 796          * Switch into the database schema
 797          */
 798         protected function applySchema() {
 799                 if ( !( $this->mSchemaSet ) ) {
 800                         $this->mSchemaSet = true;
 801                         $this->begin( __METHOD__ );
 802                         $this->doQuery( "SET SCHEMA = $this->mSchema" );
 803                         $this->commit( __METHOD__ );
 804                 }
 805         }
 806
 807         /**
 808          * Start a transaction (mandatory)
 809          */
 810         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 811                 // BEGIN is implicit for DB2
 812                 // However, it requires that AutoCommit be off.
 813
 814                 // Some MediaWiki code is still transaction-less (?).
 815                 // The strategy is to keep AutoCommit on for that code
 816                 //  but switch it off whenever a transaction is begun.
 817                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_OFF );
 818
 819                 $this->mTrxLevel = 1;
 820         }
 821
 822         /**
 823          * End a transaction
 824          * Must have a preceding begin()
 825          */
 826         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 827                 db2_commit( $this->mConn );
 828
 829                 // Some MediaWiki code is still transaction-less (?).
 830                 // The strategy is to keep AutoCommit on for that code
 831                 //  but switch it off whenever a transaction is begun.
 832                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 833
 834                 $this->mTrxLevel = 0;
 835         }
 836
 837         /**
 838          * Cancel a transaction
 839          */
 840         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 841                 db2_rollback( $this->mConn );
 842                 // turn auto-commit back on
 843                 // not sure if this is appropriate
 844                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 845                 $this->mTrxLevel = 0;
 846         }
 847
 848         /**
 849          * Makes an encoded list of strings from an array
 850          * $mode:
 851          *   LIST_COMMA         - comma separated, no field names
 852          *   LIST_AND           - ANDed WHERE clause (without the WHERE)
 853          *   LIST_OR            - ORed WHERE clause (without the WHERE)
 854          *   LIST_SET           - comma separated with field names, like a SET clause
 855          *   LIST_NAMES         - comma separated field names
 856          *   LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 857          * @return string
 858          */
 859         function makeList( $a, $mode = LIST_COMMA ) {
 860                 if ( !is_array( $a ) ) {
 861                         throw new DBUnexpectedError( $this,
 862                                 'DatabaseIbm_db2::makeList called with incorrect parameters' );
 863                 }
 864
 865                 // if this is for a prepared UPDATE statement
 866                 // (this should be promoted to the parent class
 867                 //  once other databases use prepared statements)
 868                 if ( $mode == LIST_SET_PREPARED ) {
 869                         $first = true;
 870                         $list = '';
 871                         foreach ( $a as $field => $value ) {
 872                                 if ( !$first ) {
 873                                         $list .= ", $field = ?";
 874                                 } else {
 875                                         $list .= "$field = ?";
 876                                         $first = false;
 877                                 }
 878                         }
 879                         $list .= '';
 880
 881                         return $list;
 882                 }
 883
 884                 // otherwise, call the usual function
 885                 return parent::makeList( $a, $mode );
 886         }
 887
 888         /**
 889          * Construct a LIMIT query with optional offset
 890          * This is used for query pages
 891          *
 892          * @param $sql string SQL query we will append the limit too
 893          * @param $limit integer the SQL limit
 894          * @param $offset integer the SQL offset (default false)
 895          * @return string
 896          */
 897         public function limitResult( $sql, $limit, $offset=false ) {
 898                 if( !is_numeric( $limit ) ) {
 899                         throw new DBUnexpectedError( $this,
 900                                 "Invalid non-numeric limit passed to limitResult()\n" );
 901                 }
 902                 if( $offset ) {
 903                         if ( stripos( $sql, 'where' ) === false ) {
 904                                 return "$sql AND ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 905                         } else {
 906                                 return "$sql WHERE ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 907                         }
 908                 }
 909                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 910         }
 911
 912         /**
 913          * Handle reserved keyword replacement in table names
 914          *
 915          * @param $name Object
 916          * @param $format String Ignored parameter Default 'quoted'Boolean
 917          * @return String
 918          */
 919         public function tableName( $name, $format = 'quoted' ) {
 920                 // we want maximum compatibility with MySQL schema
 921                 return $name;
 922         }
 923
 924         /**
 925          * Generates a timestamp in an insertable format
 926          *
 927          * @param $ts string timestamp
 928          * @return String: timestamp value
 929          */
 930         public function timestamp( $ts = 0 ) {
 931                 // TS_MW cannot be easily distinguished from an integer
 932                 return wfTimestamp( TS_DB2, $ts );
 933         }
 934
 935         /**
 936          * Return the next in a sequence, save the value for retrieval via insertId()
 937          * @param $seqName String: name of a defined sequence in the database
 938          * @return int next value in that sequence
 939          */
 940         public function nextSequenceValue( $seqName ) {
 941                 // Not using sequences in the primary schema to allow for easier migration
 942                 //  from MySQL
 943                 // Emulating MySQL behaviour of using NULL to signal that sequences
 944                 // aren't used
 945                 /*
 946                 $safeseq = preg_replace( "/'/", "''", $seqName );
 947                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 948                 $row = $this->fetchRow( $res );
 949                 $this->mInsertId = $row[0];
 950                 return $this->mInsertId;
 951                 */
 952                 return null;
 953         }
 954
 955         /**
 956          * This must be called after nextSequenceVal
 957          * @return int Last sequence value used as a primary key
 958          */
 959         public function insertId() {
 960                 return $this->mInsertId;
 961         }
 962
 963         /**
 964          * Updates the mInsertId property with the value of the last insert
 965          *  into a generated column
 966          *
 967          * @param $table      String: sanitized table name
 968          * @param $primaryKey Mixed: string name of the primary key
 969          * @param $stmt       Resource: prepared statement resource
 970          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
 971          */
 972         private function calcInsertId( $table, $primaryKey, $stmt ) {
 973                 if ( $primaryKey ) {
 974                         $this->mInsertId = db2_last_insert_id( $this->mConn );
 975                 }
 976         }
 977
 978         /**
 979          * INSERT wrapper, inserts an array into a table
 980          *
 981          * $args may be a single associative array, or an array of arrays
 982          *  with numeric keys, for multi-row insert
 983          *
 984          * @param $table   String: Name of the table to insert to.
 985          * @param $args    Array: Items to insert into the table.
 986          * @param $fname   String: Name of the function, for profiling
 987          * @param $options String or Array. Valid options: IGNORE
 988          *
 989          * @return bool Success of insert operation. IGNORE always returns true.
 990          */
 991         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert',
 992                 $options = array() )
 993         {
 994                 if ( !count( $args ) ) {
 995                         return true;
 996                 }
 997                 // get database-specific table name (not used)
 998                 $table = $this->tableName( $table );
 999                 // format options as an array
1000                 $options = IBM_DB2Helper::makeArray( $options );
1001                 // format args as an array of arrays
1002                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
1003                         $args = array( $args );
1004                 }
1005
1006                 // prevent insertion of NULL into primary key columns
1007                 list( $args, $primaryKeys ) = $this->removeNullPrimaryKeys( $table, $args );
1008                 // if there's only one primary key
1009                 // we'll be able to read its value after insertion
1010                 $primaryKey = false;
1011                 if ( count( $primaryKeys ) == 1 ) {
1012                         $primaryKey = $primaryKeys[0];
1013                 }
1014
1015                 // get column names
1016                 $keys = array_keys( $args[0] );
1017                 $key_count = count( $keys );
1018
1019                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
1020                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
1021
1022                 // assume success
1023                 $res = true;
1024                 // If we are not in a transaction, we need to be for savepoint trickery
1025                 if ( !$this->mTrxLevel ) {
1026                         $this->begin( __METHOD__ );
1027                 }
1028
1029                 $sql = "INSERT INTO $table ( " . implode( ',', $keys ) . ' ) VALUES ';
1030                 if ( $key_count == 1 ) {
1031                         $sql .= '( ? )';
1032                 } else {
1033                         $sql .= '( ?' . str_repeat( ',?', $key_count-1 ) . ' )';
1034                 }
1035                 $this->installPrint( "Preparing the following SQL:" );
1036                 $this->installPrint( "$sql" );
1037                 $this->installPrint( print_r( $args, true ));
1038                 $stmt = $this->prepare( $sql );
1039
1040                 // start a transaction/enter transaction mode
1041                 $this->begin( __METHOD__ );
1042
1043                 if ( !$ignore ) {
1044                         //$first = true;
1045                         foreach ( $args as $row ) {
1046                                 //$this->installPrint( "Inserting " . print_r( $row, true ));
1047                                 // insert each row into the database
1048                                 $res = $res & $this->execute( $stmt, $row );
1049                                 if ( !$res ) {
1050                                         $this->installPrint( 'Last error:' );
1051                                         $this->installPrint( $this->lastError() );
1052                                 }
1053                                 // get the last inserted value into a generated column
1054                                 $this->calcInsertId( $table, $primaryKey, $stmt );
1055                         }
1056                 } else {
1057                         $olde = error_reporting( 0 );
1058                         // For future use, we may want to track the number of actual inserts
1059                         // Right now, insert (all writes) simply return true/false
1060                         $numrowsinserted = 0;
1061
1062                         // always return true
1063                         $res = true;
1064
1065                         foreach ( $args as $row ) {
1066                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
1067                                 db2_exec( $this->mConn, $overhead, $this->mStmtOptions );
1068
1069                                 $res2 = $this->execute( $stmt, $row );
1070
1071                                 if ( !$res2 ) {
1072                                         $this->installPrint( 'Last error:' );
1073                                         $this->installPrint( $this->lastError() );
1074                                 }
1075                                 // get the last inserted value into a generated column
1076                                 $this->calcInsertId( $table, $primaryKey, $stmt );
1077
1078                                 $errNum = $this->lastErrno();
1079                                 if ( $errNum ) {
1080                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore",
1081                                                 $this->mStmtOptions );
1082                                 } else {
1083                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore",
1084                                                 $this->mStmtOptions );
1085                                         $numrowsinserted++;
1086                                 }
1087                         }
1088
1089                         $olde = error_reporting( $olde );
1090                         // Set the affected row count for the whole operation
1091                         $this->mAffectedRows = $numrowsinserted;
1092                 }
1093                 // commit either way
1094                 $this->commit( __METHOD__ );
1095                 $this->freePrepared( $stmt );
1096
1097                 return $res;
1098         }
1099
1100         /**
1101          * Given a table name and a hash of columns with values
1102          * Removes primary key columns from the hash where the value is NULL
1103          *
1104          * @param $table String: name of the table
1105          * @param $args Array of hashes of column names with values
1106          * @return Array: tuple( filtered array of columns, array of primary keys )
1107          */
1108         private function removeNullPrimaryKeys( $table, $args ) {
1109                 $schema = $this->mSchema;
1110
1111                 // find out the primary keys
1112                 $keyres = $this->doQuery( "SELECT NAME FROM SYSIBM.SYSCOLUMNS WHERE TBNAME = '"
1113                   . strtoupper( $table )
1114                   . "' AND TBCREATOR = '"
1115                   . strtoupper( $schema )
1116                   . "' AND KEYSEQ > 0" );
1117
1118                 $keys = array();
1119                 for (
1120                         $row = $this->fetchRow( $keyres );
1121                         $row != null;
1122                         $row = $this->fetchRow( $keyres )
1123                 )
1124                 {
1125                         $keys[] = strtolower( $row[0] );
1126                 }
1127                 // remove primary keys
1128                 foreach ( $args as $ai => $row ) {
1129                         foreach ( $keys as $key ) {
1130                                 if ( $row[$key] == null ) {
1131                                         unset( $row[$key] );
1132                                 }
1133                         }
1134                         $args[$ai] = $row;
1135                 }
1136                 // return modified hash
1137                 return array( $args, $keys );
1138         }
1139
1140         /**
1141          * UPDATE wrapper, takes a condition array and a SET array
1142          *
1143          * @param $table  String: The table to UPDATE
1144          * @param $values array An array of values to SET
1145          * @param $conds  array An array of conditions ( WHERE ). Use '*' to update all rows.
1146          * @param $fname  String: The Class::Function calling this function
1147          *                ( for the log )
1148          * @param $options array An array of UPDATE options, can be one or
1149          *                 more of IGNORE, LOW_PRIORITY
1150          * @return Boolean
1151          */
1152         public function update( $table, $values, $conds, $fname = 'DatabaseIbm_db2::update',
1153                 $options = array() )
1154         {
1155                 $table = $this->tableName( $table );
1156                 $opts = $this->makeUpdateOptions( $options );
1157                 $sql = "UPDATE $opts $table SET "
1158                         . $this->makeList( $values, LIST_SET_PREPARED );
1159                 if ( $conds != '*' ) {
1160                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1161                 }
1162                 $stmt = $this->prepare( $sql );
1163                 $this->installPrint( 'UPDATE: ' . print_r( $values, true ) );
1164                 // assuming for now that an array with string keys will work
1165                 // if not, convert to simple array first
1166                 $result = $this->execute( $stmt, $values );
1167                 $this->freePrepared( $stmt );
1168
1169                 return $result;
1170         }
1171
1172         /**
1173          * DELETE query wrapper
1174          *
1175          * Use $conds == "*" to delete all rows
1176          * @return bool|\ResultWrapper
1177          */
1178         public function delete( $table, $conds, $fname = 'DatabaseIbm_db2::delete' ) {
1179                 if ( !$conds ) {
1180                         throw new DBUnexpectedError( $this,
1181                                 'DatabaseIbm_db2::delete() called with no conditions' );
1182                 }
1183                 $table = $this->tableName( $table );
1184                 $sql = "DELETE FROM $table";
1185                 if ( $conds != '*' ) {
1186                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1187                 }
1188                 $result = $this->query( $sql, $fname );
1189
1190                 return $result;
1191         }
1192
1193         /**
1194          * Returns the number of rows affected by the last query or 0
1195          * @return Integer: the number of rows affected by the last query
1196          */
1197         public function affectedRows() {
1198                 if ( !is_null( $this->mAffectedRows ) ) {
1199                         // Forced result for simulated queries
1200                         return $this->mAffectedRows;
1201                 }
1202                 if( empty( $this->mLastResult ) ) {
1203                         return 0;
1204                 }
1205                 return db2_num_rows( $this->mLastResult );
1206         }
1207
1208         /**
1209          * Returns the number of rows in the result set
1210          * Has to be called right after the corresponding select query
1211          * @param $res Object result set
1212          * @return Integer: number of rows
1213          */
1214         public function numRows( $res ) {
1215                 if ( $res instanceof ResultWrapper ) {
1216                         $res = $res->result;
1217                 }
1218
1219                 if ( $this->mNumRows ) {
1220                         return $this->mNumRows;
1221                 } else {
1222                         return 0;
1223                 }
1224         }
1225
1226         /**
1227          * Moves the row pointer of the result set
1228          * @param $res Object: result set
1229          * @param $row Integer: row number
1230          * @return bool success or failure
1231          */
1232         public function dataSeek( $res, $row ) {
1233                 if ( $res instanceof ResultWrapper ) {
1234                         return $res = $res->result;
1235                 }
1236                 if ( $res instanceof IBM_DB2Result ) {
1237                         return $res->dataSeek( $row );
1238                 }
1239                 wfDebug( "dataSeek operation in DB2 database\n" );
1240                 return false;
1241         }
1242
1243         ###
1244         # Fix notices in Block.php
1245         ###
1246
1247         /**
1248          * Frees memory associated with a statement resource
1249          * @param $res Object: statement resource to free
1250          * @return Boolean success or failure
1251          */
1252         public function freeResult( $res ) {
1253                 if ( $res instanceof ResultWrapper ) {
1254                         $res = $res->result;
1255                 }
1256                 wfSuppressWarnings();
1257                 $ok = db2_free_result( $res );
1258                 wfRestoreWarnings();
1259                 if ( !$ok ) {
1260                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
1261                 }
1262         }
1263
1264         /**
1265          * Returns the number of columns in a resource
1266          * @param $res Object: statement resource
1267          * @return Number of fields/columns in resource
1268          */
1269         public function numFields( $res ) {
1270                 if ( $res instanceof ResultWrapper ) {
1271                         $res = $res->result;
1272                 }
1273                 if ( $res instanceof IBM_DB2Result ) {
1274                         $res = $res->getResult();
1275                 }
1276                 return db2_num_fields( $res );
1277         }
1278
1279         /**
1280          * Returns the nth column name
1281          * @param $res Object: statement resource
1282          * @param $n Integer: Index of field or column
1283          * @return String name of nth column
1284          */
1285         public function fieldName( $res, $n ) {
1286                 if ( $res instanceof ResultWrapper ) {
1287                         $res = $res->result;
1288                 }
1289                 if ( $res instanceof IBM_DB2Result ) {
1290                         $res = $res->getResult();
1291                 }
1292                 return db2_field_name( $res, $n );
1293         }
1294
1295         /**
1296          * SELECT wrapper
1297          *
1298          * @param $table   Array or string, table name(s) (prefix auto-added)
1299          * @param $vars    Array or string, field name(s) to be retrieved
1300          * @param $conds   Array or string, condition(s) for WHERE
1301          * @param $fname   String: calling function name (use __METHOD__)
1302          *                 for logs/profiling
1303          * @param $options array Associative array of options
1304          *                 (e.g. array( 'GROUP BY' => 'page_title' )),
1305          *                 see Database::makeSelectOptions code for list of
1306          *                 supported stuff
1307          * @param $join_conds array Associative array of table join conditions (optional)
1308          *                    (e.g. array( 'page' => array('LEFT JOIN',
1309          *                    'page_latest=rev_id') )
1310          * @return Mixed: database result resource for fetch functions or false
1311          *                 on failure
1312          */
1313         public function select( $table, $vars, $conds = '', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1314         {
1315                 $res = parent::select( $table, $vars, $conds, $fname, $options,
1316                         $join_conds );
1317                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
1318
1319                 // We must adjust for offset
1320                 if ( isset( $options['LIMIT'] ) && isset ( $options['OFFSET'] ) ) {
1321                         $limit = $options['LIMIT'];
1322                         $offset = $options['OFFSET'];
1323                 }
1324
1325                 // DB2 does not have a proper num_rows() function yet, so we must emulate
1326                 // DB2 9.5.4 and the corresponding ibm_db2 driver will introduce
1327                 //  a working one
1328                 // TODO: Yay!
1329
1330                 // we want the count
1331                 $vars2 = array( 'count( * ) as num_rows' );
1332                 // respecting just the limit option
1333                 $options2 = array();
1334                 if ( isset( $options['LIMIT'] ) ) {
1335                         $options2['LIMIT'] = $options['LIMIT'];
1336                 }
1337                 // but don't try to emulate for GROUP BY
1338                 if ( isset( $options['GROUP BY'] ) ) {
1339                         return $res;
1340                 }
1341
1342                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2,
1343                         $join_conds );
1344
1345                 $obj = $this->fetchObject( $res2 );
1346                 $this->mNumRows = $obj->num_rows;
1347
1348                 return new ResultWrapper( $this, new IBM_DB2Result( $this, $res, $obj->num_rows, $vars, $sql ) );
1349         }
1350
1351         /**
1352          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1353          * Has limited support for per-column options (colnum => 'DISTINCT')
1354          *
1355          * @private
1356          *
1357          * @param $options array Associative array of options to be turned into
1358          *              an SQL query, valid keys are listed in the function.
1359          * @return Array
1360          */
1361         function makeSelectOptions( $options ) {
1362                 $preLimitTail = $postLimitTail = '';
1363                 $startOpts = '';
1364
1365                 $noKeyOptions = array();
1366                 foreach ( $options as $key => $option ) {
1367                         if ( is_numeric( $key ) ) {
1368                                 $noKeyOptions[$option] = true;
1369                         }
1370                 }
1371
1372                 if ( isset( $options['GROUP BY'] ) ) {
1373                         $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1374                 }
1375                 if ( isset( $options['HAVING'] ) ) {
1376                         $preLimitTail .= " HAVING {$options['HAVING']}";
1377                 }
1378                 if ( isset( $options['ORDER BY'] ) ) {
1379                         $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1380                 }
1381
1382                 if ( isset( $noKeyOptions['DISTINCT'] )
1383                         || isset( $noKeyOptions['DISTINCTROW'] ) )
1384                 {
1385                         $startOpts .= 'DISTINCT';
1386                 }
1387
1388                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1389         }
1390
1391         /**
1392          * Returns link to IBM DB2 free download
1393          * @return String: wikitext of a link to the server software's web site
1394          */
1395         public static function getSoftwareLink() {
1396                 return '[http://www.ibm.com/db2/express/ IBM DB2]';
1397         }
1398
1399         /**
1400          * Get search engine class. All subclasses of this
1401          * need to implement this if they wish to use searching.
1402          *
1403          * @return String
1404          */
1405         public function getSearchEngine() {
1406                 return 'SearchIBM_DB2';
1407         }
1408
1409         /**
1410          * Did the last database access fail because of deadlock?
1411          * @return Boolean
1412          */
1413         public function wasDeadlock() {
1414                 // get SQLSTATE
1415                 $err = $this->lastErrno();
1416                 switch( $err ) {
1417                         // This is literal port of the MySQL logic and may be wrong for DB2
1418                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1419                         case '57011':   // sql0904n, Resource unavailable, no rollback
1420                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1421                         $this->installPrint( "In a deadlock because of SQLSTATE $err" );
1422                         return true;
1423                 }
1424                 return false;
1425         }
1426
1427         /**
1428          * Ping the server and try to reconnect if it there is no connection
1429          * The connection may be closed and reopened while this happens
1430          * @return Boolean: whether the connection exists
1431          */
1432         public function ping() {
1433                 // db2_ping() doesn't exist
1434                 // Emulate
1435                 $this->close();
1436                 $this->openUncataloged( $this->mDBName, $this->mUser,
1437                         $this->mPassword, $this->mServer, $this->mPort );
1438
1439                 return false;
1440         }
1441         ######################################
1442         # Unimplemented and not applicable
1443         ######################################
1444         /**
1445          * Not implemented
1446          * @return string $sql
1447          */
1448         public function limitResultForUpdate( $sql, $num ) {
1449                 $this->installPrint( 'Not implemented for DB2: limitResultForUpdate()' );
1450                 return $sql;
1451         }
1452
1453         /**
1454          * Only useful with fake prepare like in base Database class
1455          * @return      string
1456          */
1457         public function fillPreparedArg( $matches ) {
1458                 $this->installPrint( 'Not useful for DB2: fillPreparedArg()' );
1459                 return '';
1460         }
1461
1462         ######################################
1463         # Reflection
1464         ######################################
1465
1466         /**
1467          * Returns information about an index
1468          * If errors are explicitly ignored, returns NULL on failure
1469          * @param $table String: table name
1470          * @param $index String: index name
1471          * @param $fname String: function name for logging and profiling
1472          * @return Object query row in object form
1473          */
1474         public function indexInfo( $table, $index,
1475                 $fname = 'DatabaseIbm_db2::indexExists' )
1476         {
1477                 $table = $this->tableName( $table );
1478                 $sql = <<<SQL
1479 SELECT name as indexname
1480 FROM sysibm.sysindexes si
1481 WHERE si.name='$index' AND si.tbname='$table'
1482 AND sc.tbcreator='$this->mSchema'
1483 SQL;
1484                 $res = $this->query( $sql, $fname );
1485                 if ( !$res ) {
1486                         return null;
1487                 }
1488                 $row = $this->fetchObject( $res );
1489                 if ( $row != null ) {
1490                         return $row;
1491                 } else {
1492                         return false;
1493                 }
1494         }
1495
1496         /**
1497          * Returns an information object on a table column
1498          * @param $table String: table name
1499          * @param $field String: column name
1500          * @return IBM_DB2Field
1501          */
1502         public function fieldInfo( $table, $field ) {
1503                 return IBM_DB2Field::fromText( $this, $table, $field );
1504         }
1505
1506         /**
1507          * db2_field_type() wrapper
1508          * @param $res Object: result of executed statement
1509          * @param $index Mixed: number or name of the column
1510          * @return String column type
1511          */
1512         public function fieldType( $res, $index ) {
1513                 if ( $res instanceof ResultWrapper ) {
1514                         $res = $res->result;
1515                 }
1516                 if ( $res instanceof IBM_DB2Result ) {
1517                         $res = $res->getResult();
1518                 }
1519                 return db2_field_type( $res, $index );
1520         }
1521
1522         /**
1523          * Verifies that an index was created as unique
1524          * @param $table String: table name
1525          * @param $index String: index name
1526          * @param $fname string function name for profiling
1527          * @return Bool
1528          */
1529         public function indexUnique ( $table, $index,
1530                 $fname = 'DatabaseIbm_db2::indexUnique' )
1531         {
1532                 $table = $this->tableName( $table );
1533                 $sql = <<<SQL
1534 SELECT si.name as indexname
1535 FROM sysibm.sysindexes si
1536 WHERE si.name='$index' AND si.tbname='$table'
1537 AND sc.tbcreator='$this->mSchema'
1538 AND si.uniquerule IN ( 'U', 'P' )
1539 SQL;
1540                 $res = $this->query( $sql, $fname );
1541                 if ( !$res ) {
1542                         return null;
1543                 }
1544                 if ( $this->fetchObject( $res ) ) {
1545                         return true;
1546                 }
1547                 return false;
1548
1549         }
1550
1551         /**
1552          * Returns the size of a text field, or -1 for "unlimited"
1553          * @param $table String: table name
1554          * @param $field String: column name
1555          * @return Integer: length or -1 for unlimited
1556          */
1557         public function textFieldSize( $table, $field ) {
1558                 $table = $this->tableName( $table );
1559                 $sql = <<<SQL
1560 SELECT length as size
1561 FROM sysibm.syscolumns sc
1562 WHERE sc.name='$field' AND sc.tbname='$table'
1563 AND sc.tbcreator='$this->mSchema'
1564 SQL;
1565                 $res = $this->query( $sql );
1566                 $row = $this->fetchObject( $res );
1567                 $size = $row->size;
1568                 return $size;
1569         }
1570
1571         /**
1572          * Description is left as an exercise for the reader
1573          * @param $b Mixed: data to be encoded
1574          * @return IBM_DB2Blob
1575          */
1576         public function encodeBlob( $b ) {
1577                 return new IBM_DB2Blob( $b );
1578         }
1579
1580         /**
1581          * Description is left as an exercise for the reader
1582          * @param $b IBM_DB2Blob: data to be decoded
1583          * @return mixed
1584          */
1585         public function decodeBlob( $b ) {
1586                 return "$b";
1587         }
1588
1589         /**
1590          * Convert into a list of string being concatenated
1591          * @param $stringList Array: strings that need to be joined together
1592          *                    by the SQL engine
1593          * @return String: joined by the concatenation operator
1594          */
1595         public function buildConcat( $stringList ) {
1596                 // || is equivalent to CONCAT
1597                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1598                 return implode( ' || ', $stringList );
1599         }
1600
1601         /**
1602          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1603          * @param $column String: name of timestamp column
1604          * @return String: SQL code
1605          */
1606         public function extractUnixEpoch( $column ) {
1607                 // TODO
1608                 // see SpecialAncientpages
1609         }
1610
1611         ######################################
1612         # Prepared statements
1613         ######################################
1614
1615         /**
1616          * Intended to be compatible with the PEAR::DB wrapper functions.
1617          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1618          *
1619          * ? = scalar value, quoted as necessary
1620          * ! = raw SQL bit (a function for instance)
1621          * & = filename; reads the file and inserts as a blob
1622          *     (we don't use this though...)
1623          * @param $sql String: SQL statement with appropriate markers
1624          * @param $func String: Name of the function, for profiling
1625          * @return resource a prepared DB2 SQL statement
1626          */
1627         public function prepare( $sql, $func = 'DB2::prepare' ) {
1628                 $stmt = db2_prepare( $this->mConn, $sql, $this->mStmtOptions );
1629                 return $stmt;
1630         }
1631
1632         /**
1633          * Frees resources associated with a prepared statement
1634          * @return Boolean success or failure
1635          */
1636         public function freePrepared( $prepared ) {
1637                 return db2_free_stmt( $prepared );
1638         }
1639
1640         /**
1641          * Execute a prepared query with the various arguments
1642          * @param $prepared String: the prepared sql
1643          * @param $args Mixed: either an array here, or put scalars as varargs
1644          * @return Resource: results object
1645          */
1646         public function execute( $prepared, $args = null ) {
1647                 if( !is_array( $args ) ) {
1648                         # Pull the var args
1649                         $args = func_get_args();
1650                         array_shift( $args );
1651                 }
1652                 $res = db2_execute( $prepared, $args );
1653                 if ( !$res ) {
1654                         $this->installPrint( db2_stmt_errormsg() );
1655                 }
1656                 return $res;
1657         }
1658
1659         /**
1660          * Prepare & execute an SQL statement, quoting and inserting arguments
1661          * in the appropriate places.
1662          * @param $query String
1663          * @param $args ...
1664          * @return Resource
1665          */
1666         public function safeQuery( $query, $args = null ) {
1667                 // copied verbatim from Database.php
1668                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1669                 if( !is_array( $args ) ) {
1670                         # Pull the var args
1671                         $args = func_get_args();
1672                         array_shift( $args );
1673                 }
1674                 $retval = $this->execute( $prepared, $args );
1675                 $this->freePrepared( $prepared );
1676                 return $retval;
1677         }
1678
1679         /**
1680          * For faking prepared SQL statements on DBs that don't support
1681          * it directly.
1682          * @param $preparedQuery String: a 'preparable' SQL statement
1683          * @param $args Array of arguments to fill it with
1684          * @return String: executable statement
1685          */
1686         public function fillPrepared( $preparedQuery, $args ) {
1687                 reset( $args );
1688                 $this->preparedArgs =& $args;
1689
1690                 foreach ( $args as $i => $arg ) {
1691                         db2_bind_param( $preparedQuery, $i+1, $args[$i] );
1692                 }
1693
1694                 return $preparedQuery;
1695         }
1696
1697         /**
1698          * Switches module between regular and install modes
1699          * @return string
1700          */
1701         public function setMode( $mode ) {
1702                 $old = $this->mMode;
1703                 $this->mMode = $mode;
1704                 return $old;
1705         }
1706
1707         /**
1708          * Bitwise negation of a column or value in SQL
1709          * Same as (~field) in C
1710          * @param $field String
1711          * @return String
1712          */
1713         function bitNot( $field ) {
1714                 // expecting bit-fields smaller than 4bytes
1715                 return "BITNOT( $field )";
1716         }
1717
1718         /**
1719          * Bitwise AND of two columns or values in SQL
1720          * Same as (fieldLeft & fieldRight) in C
1721          * @param $fieldLeft String
1722          * @param $fieldRight String
1723          * @return String
1724          */
1725         function bitAnd( $fieldLeft, $fieldRight ) {
1726                 return "BITAND( $fieldLeft, $fieldRight )";
1727         }
1728
1729         /**
1730          * Bitwise OR of two columns or values in SQL
1731          * Same as (fieldLeft | fieldRight) in C
1732          * @param $fieldLeft String
1733          * @param $fieldRight String
1734          * @return String
1735          */
1736         function bitOr( $fieldLeft, $fieldRight ) {
1737                 return "BITOR( $fieldLeft, $fieldRight )";
1738         }
1739 }
1740
1741 class IBM_DB2Helper {
1742         public static function makeArray( $maybeArray ) {
1743                 if ( !is_array( $maybeArray ) ) {
1744                         return array( $maybeArray );
1745                 }
1746
1747                 return $maybeArray;
1748         }
1749 }