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  * Primary database interface
 108  * @ingroup Database
 109  */
 110 class DatabaseIbm_db2 extends DatabaseBase {
 111         /*
 112          * Inherited members
 113         protected $mLastQuery = '';
 114         protected $mPHPError = false;
 115
 116         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 117         protected $mOpened = false;
 118
 119         protected $mTablePrefix;
 120         protected $mFlags;
 121         protected $mTrxLevel = 0;
 122         protected $mErrorCount = 0;
 123         protected $mLBInfo = array();
 124         protected $mFakeSlaveLag = null, $mFakeMaster = false;
 125          *
 126          */
 127
 128         /** Database server port */
 129         protected $mPort = null;
 130         /** Schema for tables, stored procedures, triggers */
 131         protected $mSchema = null;
 132         /** Whether the schema has been applied in this session */
 133         protected $mSchemaSet = false;
 134         /** Result of last query */
 135         protected $mLastResult = null;
 136         /** Number of rows affected by last INSERT/UPDATE/DELETE */
 137         protected $mAffectedRows = null;
 138         /** Number of rows returned by last SELECT */
 139         protected $mNumRows = null;
 140
 141         /** Connection config options - see constructor */
 142         public $mConnOptions = array();
 143         /** Statement config options -- see constructor */
 144         public $mStmtOptions = array();
 145
 146         /** Default schema */
 147         const USE_GLOBAL = 'get from global';
 148
 149         /** Option that applies to nothing */
 150         const NONE_OPTION = 0x00;
 151         /** Option that applies to connection objects */
 152         const CONN_OPTION = 0x01;
 153         /** Option that applies to statement objects */
 154         const STMT_OPTION = 0x02;
 155
 156         /** Regular operation mode -- minimal debug messages */
 157         const REGULAR_MODE = 'regular';
 158         /** Installation mode -- lots of debug messages */
 159         const INSTALL_MODE = 'install';
 160
 161         /** Controls the level of debug message output */
 162         protected $mMode = self::REGULAR_MODE;
 163
 164         /** Last sequence value used for a primary key */
 165         protected $mInsertId = null;
 166
 167         ######################################
 168         # Getters and Setters
 169         ######################################
 170
 171         /**
 172          * Returns true if this database supports (and uses) cascading deletes
 173          */
 174         function cascadingDeletes() {
 175                 return true;
 176         }
 177
 178         /**
 179          * Returns true if this database supports (and uses) triggers (e.g. on the
 180          *  page table)
 181          */
 182         function cleanupTriggers() {
 183                 return true;
 184         }
 185
 186         /**
 187          * Returns true if this database is strict about what can be put into an
 188          *  IP field.
 189          * Specifically, it uses a NULL value instead of an empty string.
 190          */
 191         function strictIPs() {
 192                 return true;
 193         }
 194
 195         /**
 196          * Returns true if this database uses timestamps rather than integers
 197         */
 198         function realTimestamps() {
 199                 return true;
 200         }
 201
 202         /**
 203          * Returns true if this database does an implicit sort when doing GROUP BY
 204          */
 205         function implicitGroupby() {
 206                 return false;
 207         }
 208
 209         /**
 210          * Returns true if this database does an implicit order by when the column
 211          *  has an index
 212          * For example: SELECT page_title FROM page LIMIT 1
 213          */
 214         function implicitOrderby() {
 215                 return false;
 216         }
 217
 218         /**
 219          * Returns true if this database can do a native search on IP columns
 220          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 221          */
 222         function searchableIPs() {
 223                 return true;
 224         }
 225
 226         /**
 227          * Returns true if this database can use functional indexes
 228          */
 229         function functionalIndexes() {
 230                 return true;
 231         }
 232
 233         /**
 234          * Returns a unique string representing the wiki on the server
 235          */
 236         function getWikiID() {
 237                 if( $this->mSchema ) {
 238                         return "{$this->mDBname}-{$this->mSchema}";
 239                 } else {
 240                         return $this->mDBname;
 241                 }
 242         }
 243
 244         function getType() {
 245                 return 'ibm_db2';
 246         }
 247
 248         /**
 249          *
 250          * @param $server String: hostname of database server
 251          * @param $user String: username
 252          * @param $password String: password
 253          * @param $dbName String: database name on the server
 254          * @param $flags Integer: database behaviour flags (optional, unused)
 255          * @param $schema String
 256          */
 257         public function __construct( $server = false, $user = false,
 258                                                         $password = false,
 259                                                         $dbName = false, $flags = 0,
 260                                                         $schema = self::USE_GLOBAL )
 261         {
 262                 global $wgDBmwschema;
 263
 264                 if ( $schema == self::USE_GLOBAL ) {
 265                         $this->mSchema = $wgDBmwschema;
 266                 } else {
 267                         $this->mSchema = $schema;
 268                 }
 269
 270                 // configure the connection and statement objects
 271                 /*
 272                 $this->setDB2Option( 'cursor', 'DB2_SCROLLABLE',
 273                         self::CONN_OPTION | self::STMT_OPTION );
 274                 */
 275                 $this->setDB2Option( 'db2_attr_case', 'DB2_CASE_LOWER',
 276                         self::CONN_OPTION | self::STMT_OPTION );
 277                 $this->setDB2Option( 'deferred_prepare', 'DB2_DEFERRED_PREPARE_ON',
 278                         self::STMT_OPTION );
 279                 $this->setDB2Option( 'rowcount', 'DB2_ROWCOUNT_PREFETCH_ON',
 280                         self::STMT_OPTION );
 281
 282                 parent::__construct( $server, $user, $password, $dbName, DBO_TRX | $flags );
 283         }
 284
 285         /**
 286          * Enables options only if the ibm_db2 extension version supports them
 287          * @param $name String: name of the option in the options array
 288          * @param $const String: name of the constant holding the right option value
 289          * @param $type Integer: whether this is a Connection or Statement otion
 290          */
 291         private function setDB2Option( $name, $const, $type ) {
 292                 if ( defined( $const ) ) {
 293                         if ( $type & self::CONN_OPTION ) {
 294                                 $this->mConnOptions[$name] = constant( $const );
 295                         }
 296                         if ( $type & self::STMT_OPTION ) {
 297                                 $this->mStmtOptions[$name] = constant( $const );
 298                         }
 299                 } else {
 300                         $this->installPrint(
 301                                 "$const is not defined. ibm_db2 version is likely too low." );
 302                 }
 303         }
 304
 305         /**
 306          * Outputs debug information in the appropriate place
 307          * @param $string String: the relevant debug message
 308          */
 309         private function installPrint( $string ) {
 310                 wfDebug( "$string\n" );
 311                 if ( $this->mMode == self::INSTALL_MODE ) {
 312                         print "<li><pre>$string</pre></li>";
 313                         flush();
 314                 }
 315         }
 316
 317         /**
 318          * Opens a database connection and returns it
 319          * Closes any existing connection
 320          *
 321          * @param $server String: hostname
 322          * @param $user String
 323          * @param $password String
 324          * @param $dbName String: database name
 325          * @return a fresh connection
 326          */
 327         public function open( $server, $user, $password, $dbName ) {
 328                 wfProfileIn( __METHOD__ );
 329
 330                 # Load IBM DB2 driver if missing
 331                 wfDl( 'ibm_db2' );
 332
 333                 # Test for IBM DB2 support, to avoid suppressed fatal error
 334                 if ( !function_exists( 'db2_connect' ) ) {
 335                         throw new DBConnectionError( $this, "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?" );
 336                 }
 337
 338                 global $wgDBport;
 339
 340                 // Close existing connection
 341                 $this->close();
 342                 // Cache conn info
 343                 $this->mServer = $server;
 344                 $this->mPort = $port = $wgDBport;
 345                 $this->mUser = $user;
 346                 $this->mPassword = $password;
 347                 $this->mDBname = $dbName;
 348
 349                 $this->openUncataloged( $dbName, $user, $password, $server, $port );
 350
 351                 if ( !$this->mConn ) {
 352                         $this->installPrint( "DB connection error\n" );
 353                         $this->installPrint(
 354                                 "Server: $server, Database: $dbName, User: $user, Password: "
 355                                 . substr( $password, 0, 3 ) . "...\n" );
 356                         $this->installPrint( $this->lastError() . "\n" );
 357                         wfProfileOut( __METHOD__ );
 358                         wfDebug( "DB connection error\n" );
 359                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 360                         wfDebug( $this->lastError() . "\n" );
 361                         throw new DBConnectionError( $this, $this->lastError() );
 362                 }
 363
 364                 // Apply connection config
 365                 db2_set_option( $this->mConn, $this->mConnOptions, 1 );
 366                 // Some MediaWiki code is still transaction-less (?).
 367                 // The strategy is to keep AutoCommit on for that code
 368                 //  but switch it off whenever a transaction is begun.
 369                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 370
 371                 $this->mOpened = true;
 372                 $this->applySchema();
 373
 374                 wfProfileOut( __METHOD__ );
 375                 return $this->mConn;
 376         }
 377
 378         /**
 379          * Opens a cataloged database connection, sets mConn
 380          */
 381         protected function openCataloged( $dbName, $user, $password ) {
 382                 wfSuppressWarnings();
 383                 $this->mConn = db2_pconnect( $dbName, $user, $password );
 384                 wfRestoreWarnings();
 385         }
 386
 387         /**
 388          * Opens an uncataloged database connection, sets mConn
 389          */
 390         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 391         {
 392                 $dsn = "DRIVER={IBM DB2 ODBC DRIVER};DATABASE=$dbName;CHARSET=UTF-8;HOSTNAME=$server;PORT=$port;PROTOCOL=TCPIP;UID=$user;PWD=$password;";
 393                 wfSuppressWarnings();
 394                 $this->mConn = db2_pconnect($dsn, "", "", array());
 395                 wfRestoreWarnings();
 396         }
 397
 398         /**
 399          * Closes a database connection, if it is open
 400          * Returns success, true if already closed
 401          */
 402         public function close() {
 403                 $this->mOpened = false;
 404                 if ( $this->mConn ) {
 405                         if ( $this->trxLevel() > 0 ) {
 406                                 $this->commit();
 407                         }
 408                         return db2_close( $this->mConn );
 409                 } else {
 410                         return true;
 411                 }
 412         }
 413
 414         /**
 415          * Retrieves the most current database error
 416          * Forces a database rollback
 417          */
 418         public function lastError() {
 419                 $connerr = db2_conn_errormsg();
 420                 if ( $connerr ) {
 421                         //$this->rollback();
 422                         return $connerr;
 423                 }
 424                 $stmterr = db2_stmt_errormsg();
 425                 if ( $stmterr ) {
 426                         //$this->rollback();
 427                         return $stmterr;
 428                 }
 429
 430                 return false;
 431         }
 432
 433         /**
 434          * Get the last error number
 435          * Return 0 if no error
 436          * @return integer
 437          */
 438         public function lastErrno() {
 439                 $connerr = db2_conn_error();
 440                 if ( $connerr ) {
 441                         return $connerr;
 442                 }
 443                 $stmterr = db2_stmt_error();
 444                 if ( $stmterr ) {
 445                         return $stmterr;
 446                 }
 447                 return 0;
 448         }
 449
 450         /**
 451          * Is a database connection open?
 452          * @return
 453          */
 454         public function isOpen() { return $this->mOpened; }
 455
 456         /**
 457          * The DBMS-dependent part of query()
 458          * @param  $sql String: SQL query.
 459          * @return object Result object for fetch functions or false on failure
 460          */
 461         protected function doQuery( $sql ) {
 462                 $this->applySchema();
 463
 464                 // Needed to handle any UTF-8 encoding issues in the raw sql
 465                 // Note that we fully support prepared statements for DB2
 466                 // prepare() and execute() should be used instead of doQuery() whenever possible
 467                 $sql = utf8_decode($sql);
 468
 469                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 470                 if( $ret == false ) {
 471                         $error = db2_stmt_errormsg();
 472
 473                         $this->installPrint( "<pre>$sql</pre>" );
 474                         $this->installPrint( $error );
 475                         throw new DBUnexpectedError( $this, 'SQL error: '
 476                                 . htmlspecialchars( $error ) );
 477                 }
 478                 $this->mLastResult = $ret;
 479                 $this->mAffectedRows = null; // Not calculated until asked for
 480                 return $ret;
 481         }
 482
 483         /**
 484          * @return string Version information from the database
 485          */
 486         public function getServerVersion() {
 487                 $info = db2_server_info( $this->mConn );
 488                 return $info->DBMS_VER;
 489         }
 490
 491         /**
 492          * Queries whether a given table exists
 493          * @return boolean
 494          */
 495         public function tableExists( $table ) {
 496                 $schema = $this->mSchema;
 497
 498                 $sql = "SELECT COUNT( * ) FROM SYSIBM.SYSTABLES ST WHERE ST.NAME = '" .
 499                         strtoupper( $table ) .
 500                         "' AND ST.CREATOR = '" .
 501                         strtoupper( $schema ) . "'";
 502                 $res = $this->query( $sql );
 503                 if ( !$res ) {
 504                         return false;
 505                 }
 506
 507                 // If the table exists, there should be one of it
 508                 $row = $this->fetchRow( $res );
 509                 $count = $row[0];
 510                 if ( $count == '1' || $count == 1 ) {
 511                         return true;
 512                 }
 513
 514                 return false;
 515         }
 516
 517         /**
 518          * Fetch the next row from the given result object, in object form.
 519          * Fields can be retrieved with $row->fieldname, with fields acting like
 520          * member variables.
 521          *
 522          * @param $res SQL result object as returned from Database::query(), etc.
 523          * @return DB2 row object
 524          * @throws DBUnexpectedError Thrown if the database returns an error
 525          */
 526         public function fetchObject( $res ) {
 527                 if ( $res instanceof ResultWrapper ) {
 528                         $res = $res->result;
 529                 }
 530                 wfSuppressWarnings();
 531                 $row = db2_fetch_object( $res );
 532                 wfRestoreWarnings();
 533                 if( $this->lastErrno() ) {
 534                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): '
 535                                 . htmlspecialchars( $this->lastError() ) );
 536                 }
 537                 return $row;
 538         }
 539
 540         /**
 541          * Fetch the next row from the given result object, in associative array
 542          * form. Fields are retrieved with $row['fieldname'].
 543          *
 544          * @param $res SQL result object as returned from Database::query(), etc.
 545          * @return DB2 row object
 546          * @throws DBUnexpectedError Thrown if the database returns an error
 547          */
 548         public function fetchRow( $res ) {
 549                 if ( $res instanceof ResultWrapper ) {
 550                         $res = $res->result;
 551                 }
 552                 if ( db2_num_rows( $res ) > 0) {
 553                         wfSuppressWarnings();
 554                         $row = db2_fetch_array( $res );
 555                         wfRestoreWarnings();
 556                         if ( $this->lastErrno() ) {
 557                                 throw new DBUnexpectedError( $this, 'Error in fetchRow(): '
 558                                         . htmlspecialchars( $this->lastError() ) );
 559                         }
 560                         return $row;
 561                 }
 562                 return false;
 563         }
 564
 565         /**
 566          * Escapes strings
 567          * Doesn't escape numbers
 568          *
 569          * @param $s String: string to escape
 570          * @return escaped string
 571          */
 572         public function addQuotes( $s ) {
 573                 //$this->installPrint( "DB2::addQuotes( $s )\n" );
 574                 if ( is_null( $s ) ) {
 575                         return 'NULL';
 576                 } elseif ( $s instanceof Blob ) {
 577                         return "'" . $s->fetch( $s ) . "'";
 578                 } elseif ( $s instanceof IBM_DB2Blob ) {
 579                         return "'" . $this->decodeBlob( $s ) . "'";
 580                 }
 581                 $s = $this->strencode( $s );
 582                 if ( is_numeric( $s ) ) {
 583                         return $s;
 584                 } else {
 585                         return "'$s'";
 586                 }
 587         }
 588
 589         /**
 590          * Verifies that a DB2 column/field type is numeric
 591          *
 592          * @param $type String: DB2 column type
 593          * @return Boolean: true if numeric
 594          */
 595         public function is_numeric_type( $type ) {
 596                 switch ( strtoupper( $type ) ) {
 597                         case 'SMALLINT':
 598                         case 'INTEGER':
 599                         case 'INT':
 600                         case 'BIGINT':
 601                         case 'DECIMAL':
 602                         case 'REAL':
 603                         case 'DOUBLE':
 604                         case 'DECFLOAT':
 605                                 return true;
 606                 }
 607                 return false;
 608         }
 609
 610         /**
 611          * Alias for addQuotes()
 612          * @param $s String: string to escape
 613          * @return escaped string
 614          */
 615         public function strencode( $s ) {
 616                 // Bloody useless function
 617                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 618                 //  But also necessary
 619                 $s = db2_escape_string( $s );
 620                 // Wide characters are evil -- some of them look like '
 621                 $s = utf8_encode( $s );
 622                 // Fix its stupidity
 623                 $from = array(  "\\\\", "\\'",  '\\n',  '\\t',  '\\"',  '\\r' );
 624                 $to = array(            "\\",           "''",           "\n",           "\t",           '"',            "\r" );
 625                 $s = str_replace( $from, $to, $s ); // DB2 expects '', not \' escaping
 626                 return $s;
 627         }
 628
 629         /**
 630          * Switch into the database schema
 631          */
 632         protected function applySchema() {
 633                 if ( !( $this->mSchemaSet ) ) {
 634                         $this->mSchemaSet = true;
 635                         $this->begin();
 636                         $this->doQuery( "SET SCHEMA = $this->mSchema" );
 637                         $this->commit();
 638                 }
 639         }
 640
 641         /**
 642          * Start a transaction (mandatory)
 643          */
 644         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 645                 // BEGIN is implicit for DB2
 646                 // However, it requires that AutoCommit be off.
 647
 648                 // Some MediaWiki code is still transaction-less (?).
 649                 // The strategy is to keep AutoCommit on for that code
 650                 //  but switch it off whenever a transaction is begun.
 651                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_OFF );
 652
 653                 $this->mTrxLevel = 1;
 654         }
 655
 656         /**
 657          * End a transaction
 658          * Must have a preceding begin()
 659          */
 660         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 661                 db2_commit( $this->mConn );
 662
 663                 // Some MediaWiki code is still transaction-less (?).
 664                 // The strategy is to keep AutoCommit on for that code
 665                 //  but switch it off whenever a transaction is begun.
 666                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 667
 668                 $this->mTrxLevel = 0;
 669         }
 670
 671         /**
 672          * Cancel a transaction
 673          */
 674         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 675                 db2_rollback( $this->mConn );
 676                 // turn auto-commit back on
 677                 // not sure if this is appropriate
 678                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 679                 $this->mTrxLevel = 0;
 680         }
 681
 682         /**
 683          * Makes an encoded list of strings from an array
 684          * $mode:
 685          *   LIST_COMMA         - comma separated, no field names
 686          *   LIST_AND           - ANDed WHERE clause (without the WHERE)
 687          *   LIST_OR            - ORed WHERE clause (without the WHERE)
 688          *   LIST_SET           - comma separated with field names, like a SET clause
 689          *   LIST_NAMES         - comma separated field names
 690          *   LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 691          */
 692         function makeList( $a, $mode = LIST_COMMA ) {
 693                 if ( !is_array( $a ) ) {
 694                         throw new DBUnexpectedError( $this,
 695                                 'DatabaseIbm_db2::makeList called with incorrect parameters' );
 696                 }
 697
 698                 // if this is for a prepared UPDATE statement
 699                 // (this should be promoted to the parent class
 700                 //  once other databases use prepared statements)
 701                 if ( $mode == LIST_SET_PREPARED ) {
 702                         $first = true;
 703                         $list = '';
 704                         foreach ( $a as $field => $value ) {
 705                                 if ( !$first ) {
 706                                         $list .= ", $field = ?";
 707                                 } else {
 708                                         $list .= "$field = ?";
 709                                         $first = false;
 710                                 }
 711                         }
 712                         $list .= '';
 713
 714                         return $list;
 715                 }
 716
 717                 // otherwise, call the usual function
 718                 return parent::makeList( $a, $mode );
 719         }
 720
 721         /**
 722          * Construct a LIMIT query with optional offset
 723          * This is used for query pages
 724          *
 725          * @param $sql string SQL query we will append the limit too
 726          * @param $limit integer the SQL limit
 727          * @param $offset integer the SQL offset (default false)
 728          */
 729         public function limitResult( $sql, $limit, $offset=false ) {
 730                 if( !is_numeric( $limit ) ) {
 731                         throw new DBUnexpectedError( $this,
 732                                 "Invalid non-numeric limit passed to limitResult()\n" );
 733                 }
 734                 if( $offset ) {
 735                         if ( stripos( $sql, 'where' ) === false ) {
 736                                 return "$sql AND ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 737                         } else {
 738                                 return "$sql WHERE ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 739                         }
 740                 }
 741                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 742         }
 743
 744         /**
 745          * Handle reserved keyword replacement in table names
 746          *
 747          * @param $name Object
 748          * @param $name Boolean
 749          * @return String
 750          */
 751         public function tableName( $name, $quoted = true ) {
 752                 // we want maximum compatibility with MySQL schema
 753                 return $name;
 754         }
 755
 756         /**
 757          * Generates a timestamp in an insertable format
 758          *
 759          * @param $ts timestamp
 760          * @return String: timestamp value
 761          */
 762         public function timestamp( $ts = 0 ) {
 763                 // TS_MW cannot be easily distinguished from an integer
 764                 return wfTimestamp( TS_DB2, $ts );
 765         }
 766
 767         /**
 768          * Return the next in a sequence, save the value for retrieval via insertId()
 769          * @param $seqName String: name of a defined sequence in the database
 770          * @return next value in that sequence
 771          */
 772         public function nextSequenceValue( $seqName ) {
 773                 // Not using sequences in the primary schema to allow for easier migration
 774                 //  from MySQL
 775                 // Emulating MySQL behaviour of using NULL to signal that sequences
 776                 // aren't used
 777                 /*
 778                 $safeseq = preg_replace( "/'/", "''", $seqName );
 779                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 780                 $row = $this->fetchRow( $res );
 781                 $this->mInsertId = $row[0];
 782                 return $this->mInsertId;
 783                 */
 784                 return null;
 785         }
 786
 787         /**
 788          * This must be called after nextSequenceVal
 789          * @return Last sequence value used as a primary key
 790          */
 791         public function insertId() {
 792                 return $this->mInsertId;
 793         }
 794
 795         /**
 796          * Updates the mInsertId property with the value of the last insert
 797          *  into a generated column
 798          *
 799          * @param $table      String: sanitized table name
 800          * @param $primaryKey Mixed: string name of the primary key
 801          * @param $stmt       Resource: prepared statement resource
 802          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
 803          */
 804         private function calcInsertId( $table, $primaryKey, $stmt ) {
 805                 if ( $primaryKey ) {
 806                         $this->mInsertId = db2_last_insert_id( $this->mConn );
 807                 }
 808         }
 809
 810         /**
 811          * INSERT wrapper, inserts an array into a table
 812          *
 813          * $args may be a single associative array, or an array of arrays
 814          *  with numeric keys, for multi-row insert
 815          *
 816          * @param $table   String: Name of the table to insert to.
 817          * @param $args    Array: Items to insert into the table.
 818          * @param $fname   String: Name of the function, for profiling
 819          * @param $options String or Array. Valid options: IGNORE
 820          *
 821          * @return bool Success of insert operation. IGNORE always returns true.
 822          */
 823         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert',
 824                 $options = array() )
 825         {
 826                 if ( !count( $args ) ) {
 827                         return true;
 828                 }
 829                 // get database-specific table name (not used)
 830                 $table = $this->tableName( $table );
 831                 // format options as an array
 832                 $options = IBM_DB2Helper::makeArray( $options );
 833                 // format args as an array of arrays
 834                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
 835                         $args = array( $args );
 836                 }
 837
 838                 // prevent insertion of NULL into primary key columns
 839                 list( $args, $primaryKeys ) = $this->removeNullPrimaryKeys( $table, $args );
 840                 // if there's only one primary key
 841                 // we'll be able to read its value after insertion
 842                 $primaryKey = false;
 843                 if ( count( $primaryKeys ) == 1 ) {
 844                         $primaryKey = $primaryKeys[0];
 845                 }
 846
 847                 // get column names
 848                 $keys = array_keys( $args[0] );
 849                 $key_count = count( $keys );
 850
 851                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 852                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
 853
 854                 // assume success
 855                 $res = true;
 856                 // If we are not in a transaction, we need to be for savepoint trickery
 857                 if ( !$this->mTrxLevel ) {
 858                         $this->begin();
 859                 }
 860
 861                 $sql = "INSERT INTO $table ( " . implode( ',', $keys ) . ' ) VALUES ';
 862                 if ( $key_count == 1 ) {
 863                         $sql .= '( ? )';
 864                 } else {
 865                         $sql .= '( ?' . str_repeat( ',?', $key_count-1 ) . ' )';
 866                 }
 867                 $this->installPrint( "Preparing the following SQL:" );
 868                 $this->installPrint( "$sql" );
 869                 $this->installPrint( print_r( $args, true ));
 870                 $stmt = $this->prepare( $sql );
 871
 872                 // start a transaction/enter transaction mode
 873                 $this->begin();
 874
 875                 if ( !$ignore ) {
 876                         //$first = true;
 877                         foreach ( $args as $row ) {
 878                                 //$this->installPrint( "Inserting " . print_r( $row, true ));
 879                                 // insert each row into the database
 880                                 $res = $res & $this->execute( $stmt, $row );
 881                                 if ( !$res ) {
 882                                         $this->installPrint( 'Last error:' );
 883                                         $this->installPrint( $this->lastError() );
 884                                 }
 885                                 // get the last inserted value into a generated column
 886                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 887                         }
 888                 } else {
 889                         $olde = error_reporting( 0 );
 890                         // For future use, we may want to track the number of actual inserts
 891                         // Right now, insert (all writes) simply return true/false
 892                         $numrowsinserted = 0;
 893
 894                         // always return true
 895                         $res = true;
 896
 897                         foreach ( $args as $row ) {
 898                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
 899                                 db2_exec( $this->mConn, $overhead, $this->mStmtOptions );
 900
 901                                 $res2 = $this->execute( $stmt, $row );
 902
 903                                 if ( !$res2 ) {
 904                                         $this->installPrint( 'Last error:' );
 905                                         $this->installPrint( $this->lastError() );
 906                                 }
 907                                 // get the last inserted value into a generated column
 908                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 909
 910                                 $errNum = $this->lastErrno();
 911                                 if ( $errNum ) {
 912                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore",
 913                                                 $this->mStmtOptions );
 914                                 } else {
 915                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore",
 916                                                 $this->mStmtOptions );
 917                                         $numrowsinserted++;
 918                                 }
 919                         }
 920
 921                         $olde = error_reporting( $olde );
 922                         // Set the affected row count for the whole operation
 923                         $this->mAffectedRows = $numrowsinserted;
 924                 }
 925                 // commit either way
 926                 $this->commit();
 927                 $this->freePrepared( $stmt );
 928
 929                 return $res;
 930         }
 931
 932         /**
 933          * Given a table name and a hash of columns with values
 934          * Removes primary key columns from the hash where the value is NULL
 935          *
 936          * @param $table String: name of the table
 937          * @param $args Array of hashes of column names with values
 938          * @return Array: tuple( filtered array of columns, array of primary keys )
 939          */
 940         private function removeNullPrimaryKeys( $table, $args ) {
 941                 $schema = $this->mSchema;
 942
 943                 // find out the primary keys
 944                 $keyres = $this->doQuery( "SELECT NAME FROM SYSIBM.SYSCOLUMNS WHERE TBNAME = '"
 945                   . strtoupper( $table )
 946                   . "' AND TBCREATOR = '"
 947                   . strtoupper( $schema )
 948                   . "' AND KEYSEQ > 0" );
 949
 950                 $keys = array();
 951                 for (
 952                         $row = $this->fetchRow( $keyres );
 953                         $row != null;
 954                         $row = $this->fetchRow( $keyres )
 955                 )
 956                 {
 957                         $keys[] = strtolower( $row[0] );
 958                 }
 959                 // remove primary keys
 960                 foreach ( $args as $ai => $row ) {
 961                         foreach ( $keys as $key ) {
 962                                 if ( $row[$key] == null ) {
 963                                         unset( $row[$key] );
 964                                 }
 965                         }
 966                         $args[$ai] = $row;
 967                 }
 968                 // return modified hash
 969                 return array( $args, $keys );
 970         }
 971
 972         /**
 973          * UPDATE wrapper, takes a condition array and a SET array
 974          *
 975          * @param $table  String: The table to UPDATE
 976          * @param $values An array of values to SET
 977          * @param $conds  An array of conditions ( WHERE ). Use '*' to update all rows.
 978          * @param $fname  String: The Class::Function calling this function
 979          *                ( for the log )
 980          * @param $options An array of UPDATE options, can be one or
 981          *                 more of IGNORE, LOW_PRIORITY
 982          * @return Boolean
 983          */
 984         public function update( $table, $values, $conds, $fname = 'DatabaseIbm_db2::update',
 985                 $options = array() )
 986         {
 987                 $table = $this->tableName( $table );
 988                 $opts = $this->makeUpdateOptions( $options );
 989                 $sql = "UPDATE $opts $table SET "
 990                         . $this->makeList( $values, LIST_SET_PREPARED );
 991                 if ( $conds != '*' ) {
 992                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
 993                 }
 994                 $stmt = $this->prepare( $sql );
 995                 $this->installPrint( 'UPDATE: ' . print_r( $values, true ) );
 996                 // assuming for now that an array with string keys will work
 997                 // if not, convert to simple array first
 998                 $result = $this->execute( $stmt, $values );
 999                 $this->freePrepared( $stmt );
1000
1001                 return $result;
1002         }
1003
1004         /**
1005          * DELETE query wrapper
1006          *
1007          * Use $conds == "*" to delete all rows
1008          */
1009         public function delete( $table, $conds, $fname = 'DatabaseIbm_db2::delete' ) {
1010                 if ( !$conds ) {
1011                         throw new DBUnexpectedError( $this,
1012                                 'DatabaseIbm_db2::delete() called with no conditions' );
1013                 }
1014                 $table = $this->tableName( $table );
1015                 $sql = "DELETE FROM $table";
1016                 if ( $conds != '*' ) {
1017                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1018                 }
1019                 $result = $this->query( $sql, $fname );
1020
1021                 return $result;
1022         }
1023
1024         /**
1025          * Returns the number of rows affected by the last query or 0
1026          * @return Integer: the number of rows affected by the last query
1027          */
1028         public function affectedRows() {
1029                 if ( !is_null( $this->mAffectedRows ) ) {
1030                         // Forced result for simulated queries
1031                         return $this->mAffectedRows;
1032                 }
1033                 if( empty( $this->mLastResult ) ) {
1034                         return 0;
1035                 }
1036                 return db2_num_rows( $this->mLastResult );
1037         }
1038
1039         /**
1040          * Returns the number of rows in the result set
1041          * Has to be called right after the corresponding select query
1042          * @param $res Object result set
1043          * @return Integer: number of rows
1044          */
1045         public function numRows( $res ) {
1046                 if ( $res instanceof ResultWrapper ) {
1047                         $res = $res->result;
1048                 }
1049
1050                 if ( $this->mNumRows ) {
1051                         return $this->mNumRows;
1052                 } else {
1053                         return 0;
1054                 }
1055         }
1056
1057         /**
1058          * Moves the row pointer of the result set
1059          * @param $res Object: result set
1060          * @param $row Integer: row number
1061          * @return success or failure
1062          */
1063         public function dataSeek( $res, $row ) {
1064                 if ( $res instanceof ResultWrapper ) {
1065                         $res = $res->result;
1066                 }
1067                 return db2_fetch_row( $res, $row );
1068         }
1069
1070         ###
1071         # Fix notices in Block.php
1072         ###
1073
1074         /**
1075          * Frees memory associated with a statement resource
1076          * @param $res Object: statement resource to free
1077          * @return Boolean success or failure
1078          */
1079         public function freeResult( $res ) {
1080                 if ( $res instanceof ResultWrapper ) {
1081                         $res = $res->result;
1082                 }
1083                 wfSuppressWarnings();
1084                 $ok = db2_free_result( $res );
1085                 wfRestoreWarnings();
1086                 if ( !$ok ) {
1087                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
1088                 }
1089         }
1090
1091         /**
1092          * Returns the number of columns in a resource
1093          * @param $res Object: statement resource
1094          * @return Number of fields/columns in resource
1095          */
1096         public function numFields( $res ) {
1097                 if ( $res instanceof ResultWrapper ) {
1098                         $res = $res->result;
1099                 }
1100                 return db2_num_fields( $res );
1101         }
1102
1103         /**
1104          * Returns the nth column name
1105          * @param $res Object: statement resource
1106          * @param $n Integer: Index of field or column
1107          * @return String name of nth column
1108          */
1109         public function fieldName( $res, $n ) {
1110                 if ( $res instanceof ResultWrapper ) {
1111                         $res = $res->result;
1112                 }
1113                 return db2_field_name( $res, $n );
1114         }
1115
1116         /**
1117          * SELECT wrapper
1118          *
1119          * @param $table   Array or string, table name(s) (prefix auto-added)
1120          * @param $vars    Array or string, field name(s) to be retrieved
1121          * @param $conds   Array or string, condition(s) for WHERE
1122          * @param $fname   String: calling function name (use __METHOD__)
1123          *                 for logs/profiling
1124          * @param $options Associative array of options
1125          *                 (e.g. array('GROUP BY' => 'page_title')),
1126          *                 see Database::makeSelectOptions code for list of
1127          *                 supported stuff
1128          * @param $join_conds Associative array of table join conditions (optional)
1129          *                    (e.g. array( 'page' => array('LEFT JOIN',
1130          *                    'page_latest=rev_id') )
1131          * @return Mixed: database result resource for fetch functions or false
1132          *                 on failure
1133          */
1134         public function select( $table, $vars, $conds = '', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1135         {
1136                 $res = parent::select( $table, $vars, $conds, $fname, $options,
1137                         $join_conds );
1138
1139                 // We must adjust for offset
1140                 if ( isset( $options['LIMIT'] ) && isset ( $options['OFFSET'] ) ) {
1141                         $limit = $options['LIMIT'];
1142                         $offset = $options['OFFSET'];
1143                 }
1144
1145                 // DB2 does not have a proper num_rows() function yet, so we must emulate
1146                 // DB2 9.5.4 and the corresponding ibm_db2 driver will introduce
1147                 //  a working one
1148                 // TODO: Yay!
1149
1150                 // we want the count
1151                 $vars2 = array( 'count( * ) as num_rows' );
1152                 // respecting just the limit option
1153                 $options2 = array();
1154                 if ( isset( $options['LIMIT'] ) ) {
1155                         $options2['LIMIT'] = $options['LIMIT'];
1156                 }
1157                 // but don't try to emulate for GROUP BY
1158                 if ( isset( $options['GROUP BY'] ) ) {
1159                         return $res;
1160                 }
1161
1162                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2,
1163                         $join_conds );
1164                 $obj = $this->fetchObject( $res2 );
1165                 $this->mNumRows = $obj->num_rows;
1166
1167                 return $res;
1168         }
1169
1170         /**
1171          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1172          * Has limited support for per-column options (colnum => 'DISTINCT')
1173          *
1174          * @private
1175          *
1176          * @param $options Associative array of options to be turned into
1177          *              an SQL query, valid keys are listed in the function.
1178          * @return Array
1179          */
1180         function makeSelectOptions( $options ) {
1181                 $preLimitTail = $postLimitTail = '';
1182                 $startOpts = '';
1183
1184                 $noKeyOptions = array();
1185                 foreach ( $options as $key => $option ) {
1186                         if ( is_numeric( $key ) ) {
1187                                 $noKeyOptions[$option] = true;
1188                         }
1189                 }
1190
1191                 if ( isset( $options['GROUP BY'] ) ) {
1192                         $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1193                 }
1194                 if ( isset( $options['HAVING'] ) ) {
1195                         $preLimitTail .= " HAVING {$options['HAVING']}";
1196                 }
1197                 if ( isset( $options['ORDER BY'] ) ) {
1198                         $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1199                 }
1200
1201                 if ( isset( $noKeyOptions['DISTINCT'] )
1202                         || isset( $noKeyOptions['DISTINCTROW'] ) )
1203                 {
1204                         $startOpts .= 'DISTINCT';
1205                 }
1206
1207                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1208         }
1209
1210         /**
1211          * Returns link to IBM DB2 free download
1212          * @return String: wikitext of a link to the server software's web site
1213          */
1214         public static function getSoftwareLink() {
1215                 return '[http://www.ibm.com/db2/express/ IBM DB2]';
1216         }
1217
1218         /**
1219          * Get search engine class. All subclasses of this
1220          * need to implement this if they wish to use searching.
1221          *
1222          * @return String
1223          */
1224         public function getSearchEngine() {
1225                 return 'SearchIBM_DB2';
1226         }
1227
1228         /**
1229          * Did the last database access fail because of deadlock?
1230          * @return Boolean
1231          */
1232         public function wasDeadlock() {
1233                 // get SQLSTATE
1234                 $err = $this->lastErrno();
1235                 switch( $err ) {
1236                         // This is literal port of the MySQL logic and may be wrong for DB2
1237                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1238                         case '57011':   // sql0904n, Resource unavailable, no rollback
1239                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1240                         $this->installPrint( "In a deadlock because of SQLSTATE $err" );
1241                         return true;
1242                 }
1243                 return false;
1244         }
1245
1246         /**
1247          * Ping the server and try to reconnect if it there is no connection
1248          * The connection may be closed and reopened while this happens
1249          * @return Boolean: whether the connection exists
1250          */
1251         public function ping() {
1252                 // db2_ping() doesn't exist
1253                 // Emulate
1254                 $this->close();
1255                 $this->mConn = $this->openUncataloged( $this->mDBName, $this->mUser,
1256                         $this->mPassword, $this->mServer, $this->mPort );
1257
1258                 return false;
1259         }
1260         ######################################
1261         # Unimplemented and not applicable
1262         ######################################
1263         /**
1264          * Not implemented
1265          * @return string $sql
1266          */
1267         public function limitResultForUpdate( $sql, $num ) {
1268                 $this->installPrint( 'Not implemented for DB2: limitResultForUpdate()' );
1269                 return $sql;
1270         }
1271
1272         /**
1273          * Only useful with fake prepare like in base Database class
1274          * @return      string
1275          */
1276         public function fillPreparedArg( $matches ) {
1277                 $this->installPrint( 'Not useful for DB2: fillPreparedArg()' );
1278                 return '';
1279         }
1280
1281         ######################################
1282         # Reflection
1283         ######################################
1284
1285         /**
1286          * Returns information about an index
1287          * If errors are explicitly ignored, returns NULL on failure
1288          * @param $table String: table name
1289          * @param $index String: index name
1290          * @param $fname String: function name for logging and profiling
1291          * @return Object query row in object form
1292          */
1293         public function indexInfo( $table, $index,
1294                 $fname = 'DatabaseIbm_db2::indexExists' )
1295         {
1296                 $table = $this->tableName( $table );
1297                 $sql = <<<SQL
1298 SELECT name as indexname
1299 FROM sysibm.sysindexes si
1300 WHERE si.name='$index' AND si.tbname='$table'
1301 AND sc.tbcreator='$this->mSchema'
1302 SQL;
1303                 $res = $this->query( $sql, $fname );
1304                 if ( !$res ) {
1305                         return null;
1306                 }
1307                 $row = $this->fetchObject( $res );
1308                 if ( $row != null ) {
1309                         return $row;
1310                 } else {
1311                         return false;
1312                 }
1313         }
1314
1315         /**
1316          * Returns an information object on a table column
1317          * @param $table String: table name
1318          * @param $field String: column name
1319          * @return IBM_DB2Field
1320          */
1321         public function fieldInfo( $table, $field ) {
1322                 return IBM_DB2Field::fromText( $this, $table, $field );
1323         }
1324
1325         /**
1326          * db2_field_type() wrapper
1327          * @param $res Object: result of executed statement
1328          * @param $index Mixed: number or name of the column
1329          * @return String column type
1330          */
1331         public function fieldType( $res, $index ) {
1332                 if ( $res instanceof ResultWrapper ) {
1333                         $res = $res->result;
1334                 }
1335                 return db2_field_type( $res, $index );
1336         }
1337
1338         /**
1339          * Verifies that an index was created as unique
1340          * @param $table String: table name
1341          * @param $index String: index name
1342          * @param $fname function name for profiling
1343          * @return Bool
1344          */
1345         public function indexUnique ( $table, $index,
1346                 $fname = 'DatabaseIbm_db2::indexUnique' )
1347         {
1348                 $table = $this->tableName( $table );
1349                 $sql = <<<SQL
1350 SELECT si.name as indexname
1351 FROM sysibm.sysindexes si
1352 WHERE si.name='$index' AND si.tbname='$table'
1353 AND sc.tbcreator='$this->mSchema'
1354 AND si.uniquerule IN ( 'U', 'P' )
1355 SQL;
1356                 $res = $this->query( $sql, $fname );
1357                 if ( !$res ) {
1358                         return null;
1359                 }
1360                 if ( $this->fetchObject( $res ) ) {
1361                         return true;
1362                 }
1363                 return false;
1364
1365         }
1366
1367         /**
1368          * Returns the size of a text field, or -1 for "unlimited"
1369          * @param $table String: table name
1370          * @param $field String: column name
1371          * @return Integer: length or -1 for unlimited
1372          */
1373         public function textFieldSize( $table, $field ) {
1374                 $table = $this->tableName( $table );
1375                 $sql = <<<SQL
1376 SELECT length as size
1377 FROM sysibm.syscolumns sc
1378 WHERE sc.name='$field' AND sc.tbname='$table'
1379 AND sc.tbcreator='$this->mSchema'
1380 SQL;
1381                 $res = $this->query( $sql );
1382                 $row = $this->fetchObject( $res );
1383                 $size = $row->size;
1384                 return $size;
1385         }
1386
1387         /**
1388          * Description is left as an exercise for the reader
1389          * @param $b Mixed: data to be encoded
1390          * @return IBM_DB2Blob
1391          */
1392         public function encodeBlob( $b ) {
1393                 return new IBM_DB2Blob( $b );
1394         }
1395
1396         /**
1397          * Description is left as an exercise for the reader
1398          * @param $b IBM_DB2Blob: data to be decoded
1399          * @return mixed
1400          */
1401         public function decodeBlob( $b ) {
1402                 return "$b";
1403         }
1404
1405         /**
1406          * Convert into a list of string being concatenated
1407          * @param $stringList Array: strings that need to be joined together
1408          *                    by the SQL engine
1409          * @return String: joined by the concatenation operator
1410          */
1411         public function buildConcat( $stringList ) {
1412                 // || is equivalent to CONCAT
1413                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1414                 return implode( ' || ', $stringList );
1415         }
1416
1417         /**
1418          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1419          * @param $column String: name of timestamp column
1420          * @return String: SQL code
1421          */
1422         public function extractUnixEpoch( $column ) {
1423                 // TODO
1424                 // see SpecialAncientpages
1425         }
1426
1427         ######################################
1428         # Prepared statements
1429         ######################################
1430
1431         /**
1432          * Intended to be compatible with the PEAR::DB wrapper functions.
1433          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1434          *
1435          * ? = scalar value, quoted as necessary
1436          * ! = raw SQL bit (a function for instance)
1437          * & = filename; reads the file and inserts as a blob
1438          *     (we don't use this though...)
1439          * @param $sql String: SQL statement with appropriate markers
1440          * @param $func String: Name of the function, for profiling
1441          * @return resource a prepared DB2 SQL statement
1442          */
1443         public function prepare( $sql, $func = 'DB2::prepare' ) {
1444                 $stmt = db2_prepare( $this->mConn, $sql, $this->mStmtOptions );
1445                 return $stmt;
1446         }
1447
1448         /**
1449          * Frees resources associated with a prepared statement
1450          * @return Boolean success or failure
1451          */
1452         public function freePrepared( $prepared ) {
1453                 return db2_free_stmt( $prepared );
1454         }
1455
1456         /**
1457          * Execute a prepared query with the various arguments
1458          * @param $prepared String: the prepared sql
1459          * @param $args Mixed: either an array here, or put scalars as varargs
1460          * @return Resource: results object
1461          */
1462         public function execute( $prepared, $args = null ) {
1463                 if( !is_array( $args ) ) {
1464                         # Pull the var args
1465                         $args = func_get_args();
1466                         array_shift( $args );
1467                 }
1468                 $res = db2_execute( $prepared, $args );
1469                 if ( !$res ) {
1470                         $this->installPrint( db2_stmt_errormsg() );
1471                 }
1472                 return $res;
1473         }
1474
1475         /**
1476          * Prepare & execute an SQL statement, quoting and inserting arguments
1477          * in the appropriate places.
1478          * @param $query String
1479          * @param $args ...
1480          */
1481         public function safeQuery( $query, $args = null ) {
1482                 // copied verbatim from Database.php
1483                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1484                 if( !is_array( $args ) ) {
1485                         # Pull the var args
1486                         $args = func_get_args();
1487                         array_shift( $args );
1488                 }
1489                 $retval = $this->execute( $prepared, $args );
1490                 $this->freePrepared( $prepared );
1491                 return $retval;
1492         }
1493
1494         /**
1495          * For faking prepared SQL statements on DBs that don't support
1496          * it directly.
1497          * @param $preparedQuery String: a 'preparable' SQL statement
1498          * @param $args Array of arguments to fill it with
1499          * @return String: executable statement
1500          */
1501         public function fillPrepared( $preparedQuery, $args ) {
1502                 reset( $args );
1503                 $this->preparedArgs =& $args;
1504
1505                 foreach ( $args as $i => $arg ) {
1506                         db2_bind_param( $preparedQuery, $i+1, $args[$i] );
1507                 }
1508
1509                 return $preparedQuery;
1510         }
1511
1512         /**
1513          * Switches module between regular and install modes
1514          */
1515         public function setMode( $mode ) {
1516                 $old = $this->mMode;
1517                 $this->mMode = $mode;
1518                 return $old;
1519         }
1520
1521         /**
1522          * Bitwise negation of a column or value in SQL
1523          * Same as (~field) in C
1524          * @param $field String
1525          * @return String
1526          */
1527         function bitNot( $field ) {
1528                 // expecting bit-fields smaller than 4bytes
1529                 return "BITNOT( $field )";
1530         }
1531
1532         /**
1533          * Bitwise AND of two columns or values in SQL
1534          * Same as (fieldLeft & fieldRight) in C
1535          * @param $fieldLeft String
1536          * @param $fieldRight String
1537          * @return String
1538          */
1539         function bitAnd( $fieldLeft, $fieldRight ) {
1540                 return "BITAND( $fieldLeft, $fieldRight )";
1541         }
1542
1543         /**
1544          * Bitwise OR of two columns or values in SQL
1545          * Same as (fieldLeft | fieldRight) in C
1546          * @param $fieldLeft String
1547          * @param $fieldRight String
1548          * @return String
1549          */
1550         function bitOr( $fieldLeft, $fieldRight ) {
1551                 return "BITOR( $fieldLeft, $fieldRight )";
1552         }
1553 }
1554
1555 class IBM_DB2Helper {
1556         public static function makeArray( $maybeArray ) {
1557                 if ( !is_array( $maybeArray ) ) {
1558                         return array( $maybeArray );
1559                 }
1560
1561                 return $maybeArray;
1562         }
1563 }