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