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 {
  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 nullable() { 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 $mOut, $mOpened = false;
 118
 119         protected $mFailFunction;
 120         protected $mTablePrefix;
 121         protected $mFlags;
 122         protected $mTrxLevel = 0;
 123         protected $mErrorCount = 0;
 124         protected $mLBInfo = array();
 125         protected $mFakeSlaveLag = null, $mFakeMaster = false;
 126          *
 127          */
 128
 129         /** Database server port */
 130         protected $mPort = null;
 131         /** Schema for tables, stored procedures, triggers */
 132         protected $mSchema = null;
 133         /** Whether the schema has been applied in this session */
 134         protected $mSchemaSet = false;
 135         /** Result of last query */
 136         protected $mLastResult = null;
 137         /** Number of rows affected by last INSERT/UPDATE/DELETE */
 138         protected $mAffectedRows = null;
 139         /** Number of rows returned by last SELECT */
 140         protected $mNumRows = null;
 141
 142         /** Connection config options - see constructor */
 143         public $mConnOptions = array();
 144         /** Statement config options -- see constructor */
 145         public $mStmtOptions = array();
 146
 147         /** Default schema */
 148         const USE_GLOBAL = 'mediawiki';
 149
 150         /** Option that applies to nothing */
 151         const NONE_OPTION = 0x00;
 152         /** Option that applies to connection objects */
 153         const CONN_OPTION = 0x01;
 154         /** Option that applies to statement objects */
 155         const STMT_OPTION = 0x02;
 156
 157         /** Regular operation mode -- minimal debug messages */
 158         const REGULAR_MODE = 'regular';
 159         /** Installation mode -- lots of debug messages */
 160         const INSTALL_MODE = 'install';
 161
 162         /** Controls the level of debug message output */
 163         protected $mMode = self::REGULAR_MODE;
 164
 165         /** Last sequence value used for a primary key */
 166         protected $mInsertId = null;
 167
 168         ######################################
 169         # Getters and Setters
 170         ######################################
 171
 172         /**
 173          * Returns true if this database supports (and uses) cascading deletes
 174          */
 175         function cascadingDeletes() {
 176                 return true;
 177         }
 178
 179         /**
 180          * Returns true if this database supports (and uses) triggers (e.g. on the
 181          *  page table)
 182          */
 183         function cleanupTriggers() {
 184                 return true;
 185         }
 186
 187         /**
 188          * Returns true if this database is strict about what can be put into an
 189          *  IP field.
 190          * Specifically, it uses a NULL value instead of an empty string.
 191          */
 192         function strictIPs() {
 193                 return true;
 194         }
 195
 196         /**
 197          * Returns true if this database uses timestamps rather than integers
 198         */
 199         function realTimestamps() {
 200                 return true;
 201         }
 202
 203         /**
 204          * Returns true if this database does an implicit sort when doing GROUP BY
 205          */
 206         function implicitGroupby() {
 207                 return false;
 208         }
 209
 210         /**
 211          * Returns true if this database does an implicit order by when the column
 212          *  has an index
 213          * For example: SELECT page_title FROM page LIMIT 1
 214          */
 215         function implicitOrderby() {
 216                 return false;
 217         }
 218
 219         /**
 220          * Returns true if this database can do a native search on IP columns
 221          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 222          */
 223         function searchableIPs() {
 224                 return true;
 225         }
 226
 227         /**
 228          * Returns true if this database can use functional indexes
 229          */
 230         function functionalIndexes() {
 231                 return true;
 232         }
 233
 234         /**
 235          * Returns a unique string representing the wiki on the server
 236          */
 237         function getWikiID() {
 238                 if( $this->mSchema ) {
 239                         return "{$this->mDBname}-{$this->mSchema}";
 240                 } else {
 241                         return $this->mDBname;
 242                 }
 243         }
 244
 245         function getType() {
 246                 return 'ibm_db2';
 247         }
 248
 249         ######################################
 250         # Setup
 251         ######################################
 252
 253
 254         /**
 255          *
 256          * @param $server String: hostname of database server
 257          * @param $user String: username
 258          * @param $password String: password
 259          * @param $dbName String: database name on the server
 260          * @param $failFunction Callback (optional)
 261          * @param $flags Integer: database behaviour flags (optional, unused)
 262          * @param $schema String
 263          */
 264         public function DatabaseIbm_db2( $server = false, $user = false,
 265                                                         $password = false,
 266                                                         $dbName = false, $failFunction = false, $flags = 0,
 267                                                         $schema = self::USE_GLOBAL )
 268         {
 269
 270                 global $wgOut, $wgDBmwschema;
 271                 # Can't get a reference if it hasn't been set yet
 272                 if ( !isset( $wgOut ) ) {
 273                         $wgOut = null;
 274                 }
 275                 $this->mOut =& $wgOut;
 276                 $this->mFailFunction = $failFunction;
 277                 $this->mFlags = DBO_TRX | $flags;
 278
 279                 if ( $schema == self::USE_GLOBAL ) {
 280                         $this->mSchema = $wgDBmwschema;
 281                 } else {
 282                         $this->mSchema = $schema;
 283                 }
 284
 285                 // configure the connection and statement objects
 286                 $this->setDB2Option( 'db2_attr_case', 'DB2_CASE_LOWER',
 287                         self::CONN_OPTION | self::STMT_OPTION );
 288                 $this->setDB2Option( 'deferred_prepare', 'DB2_DEFERRED_PREPARE_ON',
 289                         self::STMT_OPTION );
 290                 $this->setDB2Option( 'rowcount', 'DB2_ROWCOUNT_PREFETCH_ON',
 291                         self::STMT_OPTION );
 292
 293                 $this->open( $server, $user, $password, $dbName );
 294         }
 295
 296         /**
 297          * Enables options only if the ibm_db2 extension version supports them
 298          * @param $name String: name of the option in the options array
 299          * @param $const String: name of the constant holding the right option value
 300          * @param $type Integer: whether this is a Connection or Statement otion
 301          */
 302         private function setDB2Option( $name, $const, $type ) {
 303                 if ( defined( $const ) ) {
 304                         if ( $type & self::CONN_OPTION ) {
 305                                 $this->mConnOptions[$name] = constant( $const );
 306                         }
 307                         if ( $type & self::STMT_OPTION ) {
 308                                 $this->mStmtOptions[$name] = constant( $const );
 309                         }
 310                 } else {
 311                         $this->installPrint(
 312                                 "$const is not defined. ibm_db2 version is likely too low." );
 313                 }
 314         }
 315
 316         /**
 317          * Outputs debug information in the appropriate place
 318          * @param $string String: the relevant debug message
 319          */
 320         private function installPrint( $string ) {
 321                 wfDebug( "$string\n" );
 322                 if ( $this->mMode == self::INSTALL_MODE ) {
 323                         print "<li><pre>$string</pre></li>";
 324                         flush();
 325                 }
 326         }
 327
 328         /**
 329          * Opens a database connection and returns it
 330          * Closes any existing connection
 331          *
 332          * @param $server String: hostname
 333          * @param $user String
 334          * @param $password String
 335          * @param $dbName String: database name
 336          * @return a fresh connection
 337          */
 338         public function open( $server, $user, $password, $dbName ) {
 339                 // Load the port number
 340                 global $wgDBport;
 341                 wfProfileIn( __METHOD__ );
 342
 343                 // Load IBM DB2 driver if missing
 344                 wfDl( 'ibm_db2' );
 345
 346                 // Test for IBM DB2 support, to avoid suppressed fatal error
 347                 if ( !function_exists( 'db2_connect' ) ) {
 348                         $error = <<<ERROR
 349 DB2 functions missing, have you enabled the ibm_db2 extension for PHP?
 350
 351 ERROR;
 352                         $this->installPrint( $error );
 353                         $this->reportConnectionError( $error );
 354                 }
 355
 356                 if ( strlen( $user ) < 1 ) {
 357                         return null;
 358                 }
 359
 360                 // Close existing connection
 361                 $this->close();
 362                 // Cache conn info
 363                 $this->mServer = $server;
 364                 $this->mPort = $port = $wgDBport;
 365                 $this->mUser = $user;
 366                 $this->mPassword = $password;
 367                 $this->mDBname = $dbName;
 368
 369                 $this->openUncataloged( $dbName, $user, $password, $server, $port );
 370
 371                 // Apply connection config
 372                 db2_set_option( $this->mConn, $this->mConnOptions, 1 );
 373                 // Some MediaWiki code is still transaction-less (?).
 374                 // The strategy is to keep AutoCommit on for that code
 375                 //  but switch it off whenever a transaction is begun.
 376                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 377
 378                 if ( !$this->mConn ) {
 379                         $this->installPrint( "DB connection error\n" );
 380                         $this->installPrint(
 381                                 "Server: $server, Database: $dbName, User: $user, Password: "
 382                                 . substr( $password, 0, 3 ) . "...\n" );
 383                         $this->installPrint( $this->lastError() . "\n" );
 384                         return null;
 385                 }
 386
 387                 $this->mOpened = true;
 388                 $this->applySchema();
 389
 390                 wfProfileOut( __METHOD__ );
 391                 return $this->mConn;
 392         }
 393
 394         /**
 395          * Opens a cataloged database connection, sets mConn
 396          */
 397         protected function openCataloged( $dbName, $user, $password ) {
 398                 @$this->mConn = db2_pconnect( $dbName, $user, $password );
 399         }
 400
 401         /**
 402          * Opens an uncataloged database connection, sets mConn
 403          */
 404         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 405         {
 406                 $str = "DRIVER={IBM DB2 ODBC DRIVER};";
 407                 $str .= "DATABASE=$dbName;";
 408                 $str .= "HOSTNAME=$server;";
 409                 // port was formerly validated to not be 0
 410                 $str .= "PORT=$port;";
 411                 $str .= "PROTOCOL=TCPIP;";
 412                 $str .= "UID=$user;";
 413                 $str .= "PWD=$password;";
 414
 415                 @$this->mConn = db2_pconnect( $str, $user, $password );
 416         }
 417
 418         /**
 419          * Closes a database connection, if it is open
 420          * Returns success, true if already closed
 421          */
 422         public function close() {
 423                 $this->mOpened = false;
 424                 if ( $this->mConn ) {
 425                         if ( $this->trxLevel() > 0 ) {
 426                                 $this->commit();
 427                         }
 428                         return db2_close( $this->mConn );
 429                 } else {
 430                         return true;
 431                 }
 432         }
 433
 434         /**
 435          * Returns a fresh instance of this class
 436          *
 437          * @param $server String: hostname of database server
 438          * @param $user String: username
 439          * @param $password String
 440          * @param $dbName String: database name on the server
 441          * @param $failFunction Callback (optional)
 442          * @param $flags Integer: database behaviour flags (optional, unused)
 443          * @return DatabaseIbm_db2 object
 444          */
 445         static function newFromParams( $server, $user, $password, $dbName,
 446                 $failFunction = false, $flags = 0 )
 447         {
 448                 return new DatabaseIbm_db2( $server, $user, $password, $dbName,
 449                         $failFunction, $flags );
 450         }
 451
 452         /**
 453          * Retrieves the most current database error
 454          * Forces a database rollback
 455          */
 456         public function lastError() {
 457                 $connerr = db2_conn_errormsg();
 458                 if ( $connerr ) {
 459                         //$this->rollback();
 460                         return $connerr;
 461                 }
 462                 $stmterr = db2_stmt_errormsg();
 463                 if ( $stmterr ) {
 464                         //$this->rollback();
 465                         return $stmterr;
 466                 }
 467
 468                 return false;
 469         }
 470
 471         /**
 472          * Get the last error number
 473          * Return 0 if no error
 474          * @return integer
 475          */
 476         public function lastErrno() {
 477                 $connerr = db2_conn_error();
 478                 if ( $connerr ) {
 479                         return $connerr;
 480                 }
 481                 $stmterr = db2_stmt_error();
 482                 if ( $stmterr ) {
 483                         return $stmterr;
 484                 }
 485                 return 0;
 486         }
 487
 488         /**
 489          * Is a database connection open?
 490          * @return
 491          */
 492         public function isOpen() { return $this->mOpened; }
 493
 494         /**
 495          * The DBMS-dependent part of query()
 496          * @param  $sql String: SQL query.
 497          * @return object Result object for fetch functions or false on failure
 498          * @access private
 499          */
 500         /*private*/
 501         public function doQuery( $sql ) {
 502                 $this->applySchema();
 503
 504                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 505                 if( $ret == false ) {
 506                         $error = db2_stmt_errormsg();
 507                         $this->installPrint( "<pre>$sql</pre>" );
 508                         $this->installPrint( $error );
 509                         throw new DBUnexpectedError( $this, 'SQL error: '
 510                                 . htmlspecialchars( $error ) );
 511                 }
 512                 $this->mLastResult = $ret;
 513                 $this->mAffectedRows = null; // Not calculated until asked for
 514                 return $ret;
 515         }
 516
 517         /**
 518          * @return string Version information from the database
 519          */
 520         public function getServerVersion() {
 521                 $info = db2_server_info( $this->mConn );
 522                 return $info->DBMS_VER;
 523         }
 524
 525         /**
 526          * Queries whether a given table exists
 527          * @return boolean
 528          */
 529         public function tableExists( $table ) {
 530                 $schema = $this->mSchema;
 531                 $sql = <<< EOF
 532 SELECT COUNT( * ) FROM SYSIBM.SYSTABLES ST
 533 WHERE ST.NAME = '$table' AND ST.CREATOR = '$schema'
 534 EOF;
 535                 $res = $this->query( $sql );
 536                 if ( !$res ) {
 537                         return false;
 538                 }
 539
 540                 // If the table exists, there should be one of it
 541                 @$row = $this->fetchRow( $res );
 542                 $count = $row[0];
 543                 if ( $count == '1' || $count == 1 ) {
 544                         return true;
 545                 }
 546
 547                 return false;
 548         }
 549
 550         /**
 551          * Fetch the next row from the given result object, in object form.
 552          * Fields can be retrieved with $row->fieldname, with fields acting like
 553          * member variables.
 554          *
 555          * @param $res SQL result object as returned from Database::query(), etc.
 556          * @return DB2 row object
 557          * @throws DBUnexpectedError Thrown if the database returns an error
 558          */
 559         public function fetchObject( $res ) {
 560                 if ( $res instanceof ResultWrapper ) {
 561                         $res = $res->result;
 562                 }
 563                 @$row = db2_fetch_object( $res );
 564                 if( $this->lastErrno() ) {
 565                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): '
 566                                 . htmlspecialchars( $this->lastError() ) );
 567                 }
 568                 return $row;
 569         }
 570
 571         /**
 572          * Fetch the next row from the given result object, in associative array
 573          * form. Fields are retrieved with $row['fieldname'].
 574          *
 575          * @param $res SQL result object as returned from Database::query(), etc.
 576          * @return DB2 row object
 577          * @throws DBUnexpectedError Thrown if the database returns an error
 578          */
 579         public function fetchRow( $res ) {
 580                 if ( $res instanceof ResultWrapper ) {
 581                         $res = $res->result;
 582                 }
 583                 @$row = db2_fetch_array( $res );
 584                 if ( $this->lastErrno() ) {
 585                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): '
 586                                 . htmlspecialchars( $this->lastError() ) );
 587                 }
 588                 return $row;
 589         }
 590
 591         /**
 592          * Override if introduced to base Database class
 593          */
 594         public function initial_setup() {
 595                 // do nothing
 596         }
 597
 598         /**
 599          * Create tables, stored procedures, and so on
 600          */
 601         public function setup_database() {
 602                 try {
 603                         // TODO: switch to root login if available
 604
 605                         // Switch into the correct namespace
 606                         $this->applySchema();
 607                         $this->begin();
 608
 609                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 610                         if ( $res !== true ) {
 611                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 612                         } else {
 613                                 print ' done</li>';
 614                         }
 615                         $res = $this->sourceFile( "../maintenance/ibm_db2/foreignkeys.sql" );
 616                         if ( $res !== true ) {
 617                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 618                         } else {
 619                                 print '<li>Foreign keys done</li>';
 620                         }
 621                         $res = null;
 622
 623                         // TODO: populate interwiki links
 624
 625                         if ( $this->lastError() ) {
 626                                 $this->installPrint(
 627                                         'Errors encountered during table creation -- rolled back' );
 628                                 $this->installPrint( 'Please install again' );
 629                                 $this->rollback();
 630                         } else {
 631                                 $this->commit();
 632                         }
 633                 } catch ( MWException $mwe ) {
 634                         print "<br><pre>$mwe</pre><br>";
 635                 }
 636         }
 637
 638         /**
 639          * Escapes strings
 640          * Doesn't escape numbers
 641          *
 642          * @param $s String: string to escape
 643          * @return escaped string
 644          */
 645         public function addQuotes( $s ) {
 646                 //$this->installPrint( "DB2::addQuotes( $s )\n" );
 647                 if ( is_null( $s ) ) {
 648                         return 'NULL';
 649                 } elseif ( $s instanceof Blob ) {
 650                         return "'" . $s->fetch( $s ) . "'";
 651                 } elseif ( $s instanceof IBM_DB2Blob ) {
 652                         return "'" . $this->decodeBlob( $s ) . "'";
 653                 }
 654                 $s = $this->strencode( $s );
 655                 if ( is_numeric( $s ) ) {
 656                         return $s;
 657                 } else {
 658                         return "'$s'";
 659                 }
 660         }
 661
 662         /**
 663          * Verifies that a DB2 column/field type is numeric
 664          *
 665          * @param $type String: DB2 column type
 666          * @return Boolean: true if numeric
 667          */
 668         public function is_numeric_type( $type ) {
 669                 switch ( strtoupper( $type ) ) {
 670                         case 'SMALLINT':
 671                         case 'INTEGER':
 672                         case 'INT':
 673                         case 'BIGINT':
 674                         case 'DECIMAL':
 675                         case 'REAL':
 676                         case 'DOUBLE':
 677                         case 'DECFLOAT':
 678                                 return true;
 679                 }
 680                 return false;
 681         }
 682
 683         /**
 684          * Alias for addQuotes()
 685          * @param $s String: string to escape
 686          * @return escaped string
 687          */
 688         public function strencode( $s ) {
 689                 // Bloody useless function
 690                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 691                 //  But also necessary
 692                 $s = db2_escape_string( $s );
 693                 // Wide characters are evil -- some of them look like '
 694                 $s = utf8_encode( $s );
 695                 // Fix its stupidity
 696                 $from = array(  "\\\\", "\\'",  '\\n',  '\\t',  '\\"',  '\\r' );
 697                 $to = array(            "\\",           "''",           "\n",           "\t",           '"',            "\r" );
 698                 $s = str_replace( $from, $to, $s ); // DB2 expects '', not \' escaping
 699                 return $s;
 700         }
 701
 702         /**
 703          * Switch into the database schema
 704          */
 705         protected function applySchema() {
 706                 if ( !( $this->mSchemaSet ) ) {
 707                         $this->mSchemaSet = true;
 708                         $this->begin();
 709                         $this->doQuery( "SET SCHEMA = $this->mSchema" );
 710                         $this->commit();
 711                 }
 712         }
 713
 714         /**
 715          * Start a transaction (mandatory)
 716          */
 717         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 718                 // BEGIN is implicit for DB2
 719                 // However, it requires that AutoCommit be off.
 720
 721                 // Some MediaWiki code is still transaction-less (?).
 722                 // The strategy is to keep AutoCommit on for that code
 723                 //  but switch it off whenever a transaction is begun.
 724                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_OFF );
 725
 726                 $this->mTrxLevel = 1;
 727         }
 728
 729         /**
 730          * End a transaction
 731          * Must have a preceding begin()
 732          */
 733         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 734                 db2_commit( $this->mConn );
 735
 736                 // Some MediaWiki code is still transaction-less (?).
 737                 // The strategy is to keep AutoCommit on for that code
 738                 //  but switch it off whenever a transaction is begun.
 739                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 740
 741                 $this->mTrxLevel = 0;
 742         }
 743
 744         /**
 745          * Cancel a transaction
 746          */
 747         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 748                 db2_rollback( $this->mConn );
 749                 // turn auto-commit back on
 750                 // not sure if this is appropriate
 751                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 752                 $this->mTrxLevel = 0;
 753         }
 754
 755         /**
 756          * Makes an encoded list of strings from an array
 757          * $mode:
 758          *   LIST_COMMA         - comma separated, no field names
 759          *   LIST_AND           - ANDed WHERE clause (without the WHERE)
 760          *   LIST_OR            - ORed WHERE clause (without the WHERE)
 761          *   LIST_SET           - comma separated with field names, like a SET clause
 762          *   LIST_NAMES         - comma separated field names
 763          *   LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 764          */
 765         function makeList( $a, $mode = LIST_COMMA ) {
 766                 if ( !is_array( $a ) ) {
 767                         throw new DBUnexpectedError( $this,
 768                                 'DatabaseBase::makeList called with incorrect parameters' );
 769                 }
 770
 771                 // if this is for a prepared UPDATE statement
 772                 // (this should be promoted to the parent class
 773                 //  once other databases use prepared statements)
 774                 if ( $mode == LIST_SET_PREPARED ) {
 775                         $first = true;
 776                         $list = '';
 777                         foreach ( $a as $field => $value ) {
 778                                 if ( !$first ) {
 779                                         $list .= ", $field = ?";
 780                                 } else {
 781                                         $list .= "$field = ?";
 782                                         $first = false;
 783                                 }
 784                         }
 785                         $list .= '';
 786
 787                         return $list;
 788                 }
 789
 790                 // otherwise, call the usual function
 791                 return parent::makeList( $a, $mode );
 792         }
 793
 794         /**
 795          * Construct a LIMIT query with optional offset
 796          * This is used for query pages
 797          *
 798          * @param $sql string SQL query we will append the limit too
 799          * @param $limit integer the SQL limit
 800          * @param $offset integer the SQL offset (default false)
 801          */
 802         public function limitResult( $sql, $limit, $offset=false ) {
 803                 if( !is_numeric( $limit ) ) {
 804                         throw new DBUnexpectedError( $this,
 805                                 "Invalid non-numeric limit passed to limitResult()\n" );
 806                 }
 807                 if( $offset ) {
 808                         if ( stripos( $sql, 'where' ) === false ) {
 809                                 return "$sql AND ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 810                         } else {
 811                                 return "$sql WHERE ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 812                         }
 813                 }
 814                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 815         }
 816
 817         /**
 818          * Handle reserved keyword replacement in table names
 819          *
 820          * @param $name Object
 821          * @return String
 822          */
 823         public function tableName( $name ) {
 824                 // we want maximum compatibility with MySQL schema
 825                 return $name;
 826         }
 827
 828         /**
 829          * Generates a timestamp in an insertable format
 830          *
 831          * @param $ts timestamp
 832          * @return String: timestamp value
 833          */
 834         public function timestamp( $ts = 0 ) {
 835                 // TS_MW cannot be easily distinguished from an integer
 836                 return wfTimestamp( TS_DB2, $ts );
 837         }
 838
 839         /**
 840          * Return the next in a sequence, save the value for retrieval via insertId()
 841          * @param $seqName String: name of a defined sequence in the database
 842          * @return next value in that sequence
 843          */
 844         public function nextSequenceValue( $seqName ) {
 845                 // Not using sequences in the primary schema to allow for easier migration
 846                 //  from MySQL
 847                 // Emulating MySQL behaviour of using NULL to signal that sequences
 848                 // aren't used
 849                 /*
 850                 $safeseq = preg_replace( "/'/", "''", $seqName );
 851                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 852                 $row = $this->fetchRow( $res );
 853                 $this->mInsertId = $row[0];
 854                 return $this->mInsertId;
 855                 */
 856                 return null;
 857         }
 858
 859         /**
 860          * This must be called after nextSequenceVal
 861          * @return Last sequence value used as a primary key
 862          */
 863         public function insertId() {
 864                 return $this->mInsertId;
 865         }
 866
 867         /**
 868          * Updates the mInsertId property with the value of the last insert
 869          *  into a generated column
 870          *
 871          * @param $table      String: sanitized table name
 872          * @param $primaryKey Mixed: string name of the primary key
 873          * @param $stmt       Resource: prepared statement resource
 874          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
 875          */
 876         private function calcInsertId( $table, $primaryKey, $stmt ) {
 877                 if ( $primaryKey ) {
 878                         $this->mInsertId = db2_last_insert_id( $this->mConn );
 879                 }
 880         }
 881
 882         /**
 883          * INSERT wrapper, inserts an array into a table
 884          *
 885          * $args may be a single associative array, or an array of arrays
 886          *  with numeric keys, for multi-row insert
 887          *
 888          * @param $table   String: Name of the table to insert to.
 889          * @param $args    Array: Items to insert into the table.
 890          * @param $fname   String: Name of the function, for profiling
 891          * @param $options String or Array. Valid options: IGNORE
 892          *
 893          * @return bool Success of insert operation. IGNORE always returns true.
 894          */
 895         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert',
 896                 $options = array() )
 897         {
 898                 if ( !count( $args ) ) {
 899                         return true;
 900                 }
 901                 // get database-specific table name (not used)
 902                 $table = $this->tableName( $table );
 903                 // format options as an array
 904                 $options = IBM_DB2Helper::makeArray( $options );
 905                 // format args as an array of arrays
 906                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
 907                         $args = array( $args );
 908                 }
 909
 910                 // prevent insertion of NULL into primary key columns
 911                 list( $args, $primaryKeys ) = $this->removeNullPrimaryKeys( $table, $args );
 912                 // if there's only one primary key
 913                 // we'll be able to read its value after insertion
 914                 $primaryKey = false;
 915                 if ( count( $primaryKeys ) == 1 ) {
 916                         $primaryKey = $primaryKeys[0];
 917                 }
 918
 919                 // get column names
 920                 $keys = array_keys( $args[0] );
 921                 $key_count = count( $keys );
 922
 923                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 924                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
 925
 926                 // assume success
 927                 $res = true;
 928                 // If we are not in a transaction, we need to be for savepoint trickery
 929                 if ( !$this->mTrxLevel ) {
 930                         $this->begin();
 931                 }
 932
 933                 $sql = "INSERT INTO $table ( " . implode( ',', $keys ) . ' ) VALUES ';
 934                 if ( $key_count == 1 ) {
 935                         $sql .= '( ? )';
 936                 } else {
 937                         $sql .= '( ?' . str_repeat( ',?', $key_count-1 ) . ' )';
 938                 }
 939                 //$this->installPrint( "Preparing the following SQL:" );
 940                 //$this->installPrint( "$sql" );
 941                 //$this->installPrint( print_r( $args, true ));
 942                 $stmt = $this->prepare( $sql );
 943
 944                 // start a transaction/enter transaction mode
 945                 $this->begin();
 946
 947                 if ( !$ignore ) {
 948                         //$first = true;
 949                         foreach ( $args as $row ) {
 950                                 //$this->installPrint( "Inserting " . print_r( $row, true ));
 951                                 // insert each row into the database
 952                                 $res = $res & $this->execute( $stmt, $row );
 953                                 if ( !$res ) {
 954                                         $this->installPrint( 'Last error:' );
 955                                         $this->installPrint( $this->lastError() );
 956                                 }
 957                                 // get the last inserted value into a generated column
 958                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 959                         }
 960                 } else {
 961                         $olde = error_reporting( 0 );
 962                         // For future use, we may want to track the number of actual inserts
 963                         // Right now, insert (all writes) simply return true/false
 964                         $numrowsinserted = 0;
 965
 966                         // always return true
 967                         $res = true;
 968
 969                         foreach ( $args as $row ) {
 970                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
 971                                 db2_exec( $this->mConn, $overhead, $this->mStmtOptions );
 972
 973                                 $this->execute( $stmt, $row );
 974
 975                                 if ( !$res2 ) {
 976                                         $this->installPrint( 'Last error:' );
 977                                         $this->installPrint( $this->lastError() );
 978                                 }
 979                                 // get the last inserted value into a generated column
 980                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 981
 982                                 $errNum = $this->lastErrno();
 983                                 if ( $errNum ) {
 984                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore",
 985                                                 $this->mStmtOptions );
 986                                 } else {
 987                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore",
 988                                                 $this->mStmtOptions );
 989                                         $numrowsinserted++;
 990                                 }
 991                         }
 992
 993                         $olde = error_reporting( $olde );
 994                         // Set the affected row count for the whole operation
 995                         $this->mAffectedRows = $numrowsinserted;
 996                 }
 997                 // commit either way
 998                 $this->commit();
 999                 $this->freePrepared( $stmt );
1000
1001                 return $res;
1002         }
1003
1004         /**
1005          * Given a table name and a hash of columns with values
1006          * Removes primary key columns from the hash where the value is NULL
1007          *
1008          * @param $table String: name of the table
1009          * @param $args Array of hashes of column names with values
1010          * @return Array: tuple( filtered array of columns, array of primary keys )
1011          */
1012         private function removeNullPrimaryKeys( $table, $args ) {
1013                 $schema = $this->mSchema;
1014                 // find out the primary keys
1015                 $keyres = db2_primary_keys( $this->mConn, null, strtoupper( $schema ),
1016                         strtoupper( $table )
1017                 );
1018                 $keys = array();
1019                 for (
1020                         $row = $this->fetchObject( $keyres );
1021                         $row != null;
1022                         $row = $this->fetchObject( $keyres )
1023                 )
1024                 {
1025                         $keys[] = strtolower( $row->column_name );
1026                 }
1027                 // remove primary keys
1028                 foreach ( $args as $ai => $row ) {
1029                         foreach ( $keys as $ki => $key ) {
1030                                 if ( $row[$key] == null ) {
1031                                         unset( $row[$key] );
1032                                 }
1033                         }
1034                         $args[$ai] = $row;
1035                 }
1036                 // return modified hash
1037                 return array( $args, $keys );
1038         }
1039
1040         /**
1041          * UPDATE wrapper, takes a condition array and a SET array
1042          *
1043          * @param $table  String: The table to UPDATE
1044          * @param $values An array of values to SET
1045          * @param $conds  An array of conditions ( WHERE ). Use '*' to update all rows.
1046          * @param $fname  String: The Class::Function calling this function
1047          *                ( for the log )
1048          * @param $options An array of UPDATE options, can be one or
1049          *                 more of IGNORE, LOW_PRIORITY
1050          * @return Boolean
1051          */
1052         public function update( $table, $values, $conds, $fname = 'Database::update',
1053                 $options = array() )
1054         {
1055                 $table = $this->tableName( $table );
1056                 $opts = $this->makeUpdateOptions( $options );
1057                 $sql = "UPDATE $opts $table SET "
1058                         . $this->makeList( $values, LIST_SET_PREPARED );
1059                 if ( $conds != '*' ) {
1060                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1061                 }
1062                 $stmt = $this->prepare( $sql );
1063                 $this->installPrint( 'UPDATE: ' . print_r( $values, true ) );
1064                 // assuming for now that an array with string keys will work
1065                 // if not, convert to simple array first
1066                 $result = $this->execute( $stmt, $values );
1067                 $this->freePrepared( $stmt );
1068
1069                 return $result;
1070         }
1071
1072         /**
1073          * DELETE query wrapper
1074          *
1075          * Use $conds == "*" to delete all rows
1076          */
1077         public function delete( $table, $conds, $fname = 'Database::delete' ) {
1078                 if ( !$conds ) {
1079                         throw new DBUnexpectedError( $this,
1080                         'Database::delete() called with no conditions' );
1081                 }
1082                 $table = $this->tableName( $table );
1083                 $sql = "DELETE FROM $table";
1084                 if ( $conds != '*' ) {
1085                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1086                 }
1087                 $result = $this->query( $sql, $fname );
1088
1089                 return $result;
1090         }
1091
1092         /**
1093          * Returns the number of rows affected by the last query or 0
1094          * @return Integer: the number of rows affected by the last query
1095          */
1096         public function affectedRows() {
1097                 if ( !is_null( $this->mAffectedRows ) ) {
1098                         // Forced result for simulated queries
1099                         return $this->mAffectedRows;
1100                 }
1101                 if( empty( $this->mLastResult ) ) {
1102                         return 0;
1103                 }
1104                 return db2_num_rows( $this->mLastResult );
1105         }
1106
1107         /**
1108          * Simulates REPLACE with a DELETE followed by INSERT
1109          * @param $table Object
1110          * @param $uniqueIndexes Array consisting of indexes and arrays of indexes
1111          * @param $rows Array: rows to insert
1112          * @param $fname String: name of the function for profiling
1113          * @return nothing
1114          */
1115         function replace( $table, $uniqueIndexes, $rows,
1116                 $fname = 'DatabaseIbm_db2::replace' )
1117         {
1118                 $table = $this->tableName( $table );
1119
1120                 if ( count( $rows )==0 ) {
1121                         return;
1122                 }
1123
1124                 # Single row case
1125                 if ( !is_array( reset( $rows ) ) ) {
1126                         $rows = array( $rows );
1127                 }
1128
1129                 foreach( $rows as $row ) {
1130                         # Delete rows which collide
1131                         if ( $uniqueIndexes ) {
1132                                 $sql = "DELETE FROM $table WHERE ";
1133                                 $first = true;
1134                                 foreach ( $uniqueIndexes as $index ) {
1135                                         if ( $first ) {
1136                                                 $first = false;
1137                                                 $sql .= '( ';
1138                                         } else {
1139                                                 $sql .= ' ) OR ( ';
1140                                         }
1141                                         if ( is_array( $index ) ) {
1142                                                 $first2 = true;
1143                                                 foreach ( $index as $col ) {
1144                                                         if ( $first2 ) {
1145                                                                 $first2 = false;
1146                                                         } else {
1147                                                                 $sql .= ' AND ';
1148                                                         }
1149                                                         $sql .= $col . '=' . $this->addQuotes( $row[$col] );
1150                                                 }
1151                                         } else {
1152                                                 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
1153                                         }
1154                                 }
1155                                 $sql .= ' )';
1156                                 $this->query( $sql, $fname );
1157                         }
1158
1159                         # Now insert the row
1160                         $sql = "INSERT INTO $table ( "
1161                                 . $this->makeList( array_keys( $row ), LIST_NAMES )
1162                                 .' ) VALUES ( ' . $this->makeList( $row, LIST_COMMA ) . ' )';
1163                         $this->query( $sql, $fname );
1164                 }
1165         }
1166
1167         /**
1168          * Returns the number of rows in the result set
1169          * Has to be called right after the corresponding select query
1170          * @param $res Object result set
1171          * @return Integer: number of rows
1172          */
1173         public function numRows( $res ) {
1174                 if ( $res instanceof ResultWrapper ) {
1175                         $res = $res->result;
1176                 }
1177                 if ( $this->mNumRows ) {
1178                         return $this->mNumRows;
1179                 } else {
1180                         return 0;
1181                 }
1182         }
1183
1184         /**
1185          * Moves the row pointer of the result set
1186          * @param $res Object: result set
1187          * @param $row Integer: row number
1188          * @return success or failure
1189          */
1190         public function dataSeek( $res, $row ) {
1191                 if ( $res instanceof ResultWrapper ) {
1192                         $res = $res->result;
1193                 }
1194                 return db2_fetch_row( $res, $row );
1195         }
1196
1197         ###
1198         # Fix notices in Block.php
1199         ###
1200
1201         /**
1202          * Frees memory associated with a statement resource
1203          * @param $res Object: statement resource to free
1204          * @return Boolean success or failure
1205          */
1206         public function freeResult( $res ) {
1207                 if ( $res instanceof ResultWrapper ) {
1208                         $res = $res->result;
1209                 }
1210                 if ( !@db2_free_result( $res ) ) {
1211                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
1212                 }
1213         }
1214
1215         /**
1216          * Returns the number of columns in a resource
1217          * @param $res Object: statement resource
1218          * @return Number of fields/columns in resource
1219          */
1220         public function numFields( $res ) {
1221                 if ( $res instanceof ResultWrapper ) {
1222                         $res = $res->result;
1223                 }
1224                 return db2_num_fields( $res );
1225         }
1226
1227         /**
1228          * Returns the nth column name
1229          * @param $res Object: statement resource
1230          * @param $n Integer: Index of field or column
1231          * @return String name of nth column
1232          */
1233         public function fieldName( $res, $n ) {
1234                 if ( $res instanceof ResultWrapper ) {
1235                         $res = $res->result;
1236                 }
1237                 return db2_field_name( $res, $n );
1238         }
1239
1240         /**
1241          * SELECT wrapper
1242          *
1243          * @param $table   Array or string, table name(s) (prefix auto-added)
1244          * @param $vars    Array or string, field name(s) to be retrieved
1245          * @param $conds   Array or string, condition(s) for WHERE
1246          * @param $fname   String: calling function name (use __METHOD__)
1247          *                 for logs/profiling
1248          * @param $options Associative array of options
1249          *                 (e.g. array('GROUP BY' => 'page_title')),
1250          *                 see Database::makeSelectOptions code for list of
1251          *                 supported stuff
1252          * @param $join_conds Associative array of table join conditions (optional)
1253          *                    (e.g. array( 'page' => array('LEFT JOIN',
1254          *                    'page_latest=rev_id') )
1255          * @return Mixed: database result resource for fetch functions or false
1256          *                 on failure
1257          */
1258         public function select( $table, $vars, $conds = '', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1259         {
1260                 $res = parent::select( $table, $vars, $conds, $fname, $options,
1261                         $join_conds );
1262
1263                 // We must adjust for offset
1264                 if ( isset( $options['LIMIT'] ) ) {
1265                         if ( isset ( $options['OFFSET'] ) ) {
1266                                 $limit = $options['LIMIT'];
1267                                 $offset = $options['OFFSET'];
1268                         }
1269                 }
1270
1271
1272                 // DB2 does not have a proper num_rows() function yet, so we must emulate
1273                 // DB2 9.5.4 and the corresponding ibm_db2 driver will introduce
1274                 //  a working one
1275                 // TODO: Yay!
1276
1277                 // we want the count
1278                 $vars2 = array( 'count( * ) as num_rows' );
1279                 // respecting just the limit option
1280                 $options2 = array();
1281                 if ( isset( $options['LIMIT'] ) ) {
1282                         $options2['LIMIT'] = $options['LIMIT'];
1283                 }
1284                 // but don't try to emulate for GROUP BY
1285                 if ( isset( $options['GROUP BY'] ) ) {
1286                         return $res;
1287                 }
1288
1289                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2,
1290                         $join_conds );
1291                 $obj = $this->fetchObject( $res2 );
1292                 $this->mNumRows = $obj->num_rows;
1293
1294                 return $res;
1295         }
1296
1297         /**
1298          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1299          * Has limited support for per-column options (colnum => 'DISTINCT')
1300          *
1301          * @private
1302          *
1303          * @param $options Associative array of options to be turned into
1304          *              an SQL query, valid keys are listed in the function.
1305          * @return Array
1306          */
1307         function makeSelectOptions( $options ) {
1308                 $preLimitTail = $postLimitTail = '';
1309                 $startOpts = '';
1310
1311                 $noKeyOptions = array();
1312                 foreach ( $options as $key => $option ) {
1313                         if ( is_numeric( $key ) ) {
1314                                 $noKeyOptions[$option] = true;
1315                         }
1316                 }
1317
1318                 if ( isset( $options['GROUP BY'] ) ) {
1319                         $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1320                 }
1321                 if ( isset( $options['HAVING'] ) ) {
1322                         $preLimitTail .= " HAVING {$options['HAVING']}";
1323                 }
1324                 if ( isset( $options['ORDER BY'] ) ) {
1325                         $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1326                 }
1327
1328                 if ( isset( $noKeyOptions['DISTINCT'] )
1329                         || isset( $noKeyOptions['DISTINCTROW'] ) )
1330                 {
1331                         $startOpts .= 'DISTINCT';
1332                 }
1333
1334                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1335         }
1336
1337         /**
1338          * Returns link to IBM DB2 free download
1339          * @return String: wikitext of a link to the server software's web site
1340          */
1341         public static function getSoftwareLink() {
1342                 return '[http://www.ibm.com/db2/express/ IBM DB2]';
1343         }
1344
1345         /**
1346          * Get search engine class. All subclasses of this
1347          * need to implement this if they wish to use searching.
1348          *
1349          * @return String
1350          */
1351         public function getSearchEngine() {
1352                 return 'SearchIBM_DB2';
1353         }
1354
1355         /**
1356          * Did the last database access fail because of deadlock?
1357          * @return Boolean
1358          */
1359         public function wasDeadlock() {
1360                 // get SQLSTATE
1361                 $err = $this->lastErrno();
1362                 switch( $err ) {
1363                         // This is literal port of the MySQL logic and may be wrong for DB2
1364                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1365                         case '57011':   // sql0904n, Resource unavailable, no rollback
1366                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1367                         $this->installPrint( "In a deadlock because of SQLSTATE $err" );
1368                         return true;
1369                 }
1370                 return false;
1371         }
1372
1373         /**
1374          * Ping the server and try to reconnect if it there is no connection
1375          * The connection may be closed and reopened while this happens
1376          * @return Boolean: whether the connection exists
1377          */
1378         public function ping() {
1379                 // db2_ping() doesn't exist
1380                 // Emulate
1381                 $this->close();
1382                 $this->mConn = $this->openUncataloged( $this->mDBName, $this->mUser,
1383                         $this->mPassword, $this->mServer, $this->mPort );
1384
1385                 return false;
1386         }
1387         ######################################
1388         # Unimplemented and not applicable
1389         ######################################
1390         /**
1391          * Not implemented
1392          * @return string ''
1393          */
1394         public function getStatus( $which = '%' ) {
1395                 $this->installPrint( 'Not implemented for DB2: getStatus()' );
1396                 return '';
1397         }
1398         /**
1399          * Not implemented
1400          * @return string $sql
1401          */
1402         public function limitResultForUpdate( $sql, $num ) {
1403                 $this->installPrint( 'Not implemented for DB2: limitResultForUpdate()' );
1404                 return $sql;
1405         }
1406
1407         /**
1408          * Only useful with fake prepare like in base Database class
1409          * @return      string
1410          */
1411         public function fillPreparedArg( $matches ) {
1412                 $this->installPrint( 'Not useful for DB2: fillPreparedArg()' );
1413                 return '';
1414         }
1415
1416         ######################################
1417         # Reflection
1418         ######################################
1419
1420         /**
1421          * Returns information about an index
1422          * If errors are explicitly ignored, returns NULL on failure
1423          * @param $table String: table name
1424          * @param $index String: index name
1425          * @param $fname String: function name for logging and profiling
1426          * @return Object query row in object form
1427          */
1428         public function indexInfo( $table, $index,
1429                 $fname = 'DatabaseIbm_db2::indexExists' )
1430         {
1431                 $table = $this->tableName( $table );
1432                 $sql = <<<SQL
1433 SELECT name as indexname
1434 FROM sysibm.sysindexes si
1435 WHERE si.name='$index' AND si.tbname='$table'
1436 AND sc.tbcreator='$this->mSchema'
1437 SQL;
1438                 $res = $this->query( $sql, $fname );
1439                 if ( !$res ) {
1440                         return null;
1441                 }
1442                 $row = $this->fetchObject( $res );
1443                 if ( $row != null ) {
1444                         return $row;
1445                 } else {
1446                         return false;
1447                 }
1448         }
1449
1450         /**
1451          * Returns an information object on a table column
1452          * @param $table String: table name
1453          * @param $field String: column name
1454          * @return IBM_DB2Field
1455          */
1456         public function fieldInfo( $table, $field ) {
1457                 return IBM_DB2Field::fromText( $this, $table, $field );
1458         }
1459
1460         /**
1461          * db2_field_type() wrapper
1462          * @param $res Object: result of executed statement
1463          * @param $index Mixed: number or name of the column
1464          * @return String column type
1465          */
1466         public function fieldType( $res, $index ) {
1467                 if ( $res instanceof ResultWrapper ) {
1468                         $res = $res->result;
1469                 }
1470                 return db2_field_type( $res, $index );
1471         }
1472
1473         /**
1474          * Verifies that an index was created as unique
1475          * @param $table String: table name
1476          * @param $index String: index name
1477          * @param $fname function name for profiling
1478          * @return Bool
1479          */
1480         public function indexUnique ( $table, $index,
1481                 $fname = 'Database::indexUnique' )
1482         {
1483                 $table = $this->tableName( $table );
1484                 $sql = <<<SQL
1485 SELECT si.name as indexname
1486 FROM sysibm.sysindexes si
1487 WHERE si.name='$index' AND si.tbname='$table'
1488 AND sc.tbcreator='$this->mSchema'
1489 AND si.uniquerule IN ( 'U', 'P' )
1490 SQL;
1491                 $res = $this->query( $sql, $fname );
1492                 if ( !$res ) {
1493                         return null;
1494                 }
1495                 if ( $this->fetchObject( $res ) ) {
1496                         return true;
1497                 }
1498                 return false;
1499
1500         }
1501
1502         /**
1503          * Returns the size of a text field, or -1 for "unlimited"
1504          * @param $table String: table name
1505          * @param $field String: column name
1506          * @return Integer: length or -1 for unlimited
1507          */
1508         public function textFieldSize( $table, $field ) {
1509                 $table = $this->tableName( $table );
1510                 $sql = <<<SQL
1511 SELECT length as size
1512 FROM sysibm.syscolumns sc
1513 WHERE sc.name='$field' AND sc.tbname='$table'
1514 AND sc.tbcreator='$this->mSchema'
1515 SQL;
1516                 $res = $this->query( $sql );
1517                 $row = $this->fetchObject( $res );
1518                 $size = $row->size;
1519                 return $size;
1520         }
1521
1522         /**
1523          * DELETE where the condition is a join
1524          * @param $delTable String: deleting from this table
1525          * @param $joinTable String: using data from this table
1526          * @param $delVar String: variable in deleteable table
1527          * @param $joinVar String: variable in data table
1528          * @param $conds Array: conditionals for join table
1529          * @param $fname String: function name for profiling
1530          */
1531         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar,
1532                 $conds, $fname = "DatabaseIbm_db2::deleteJoin" )
1533         {
1534                 if ( !$conds ) {
1535                         throw new DBUnexpectedError( $this,
1536                         'Database::deleteJoin() called with empty $conds' );
1537                 }
1538
1539                 $delTable = $this->tableName( $delTable );
1540                 $joinTable = $this->tableName( $joinTable );
1541                 $sql = <<<SQL
1542 DELETE FROM $delTable
1543 WHERE $delVar IN (
1544   SELECT $joinVar FROM $joinTable
1545
1546 SQL;
1547                 if ( $conds != '*' ) {
1548                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1549                 }
1550                 $sql .= ' )';
1551
1552                 $this->query( $sql, $fname );
1553         }
1554
1555         /**
1556          * Description is left as an exercise for the reader
1557          * @param $b Mixed: data to be encoded
1558          * @return IBM_DB2Blob
1559          */
1560         public function encodeBlob( $b ) {
1561                 return new IBM_DB2Blob( $b );
1562         }
1563
1564         /**
1565          * Description is left as an exercise for the reader
1566          * @param $b IBM_DB2Blob: data to be decoded
1567          * @return mixed
1568          */
1569         public function decodeBlob( $b ) {
1570                 return "$b";
1571         }
1572
1573         /**
1574          * Convert into a list of string being concatenated
1575          * @param $stringList Array: strings that need to be joined together
1576          *                    by the SQL engine
1577          * @return String: joined by the concatenation operator
1578          */
1579         public function buildConcat( $stringList ) {
1580                 // || is equivalent to CONCAT
1581                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1582                 return implode( ' || ', $stringList );
1583         }
1584
1585         /**
1586          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1587          * @param $column String: name of timestamp column
1588          * @return String: SQL code
1589          */
1590         public function extractUnixEpoch( $column ) {
1591                 // TODO
1592                 // see SpecialAncientpages
1593         }
1594
1595         ######################################
1596         # Prepared statements
1597         ######################################
1598
1599         /**
1600          * Intended to be compatible with the PEAR::DB wrapper functions.
1601          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1602          *
1603          * ? = scalar value, quoted as necessary
1604          * ! = raw SQL bit (a function for instance)
1605          * & = filename; reads the file and inserts as a blob
1606          *     (we don't use this though...)
1607          * @param $sql String: SQL statement with appropriate markers
1608          * @param $func String: Name of the function, for profiling
1609          * @return resource a prepared DB2 SQL statement
1610          */
1611         public function prepare( $sql, $func = 'DB2::prepare' ) {
1612                 $stmt = db2_prepare( $this->mConn, $sql, $this->mStmtOptions );
1613                 return $stmt;
1614         }
1615
1616         /**
1617          * Frees resources associated with a prepared statement
1618          * @return Boolean success or failure
1619          */
1620         public function freePrepared( $prepared ) {
1621                 return db2_free_stmt( $prepared );
1622         }
1623
1624         /**
1625          * Execute a prepared query with the various arguments
1626          * @param $prepared String: the prepared sql
1627          * @param $args Mixed: either an array here, or put scalars as varargs
1628          * @return Resource: results object
1629          */
1630         public function execute( $prepared, $args = null ) {
1631                 if( !is_array( $args ) ) {
1632                         # Pull the var args
1633                         $args = func_get_args();
1634                         array_shift( $args );
1635                 }
1636                 $res = db2_execute( $prepared, $args );
1637                 if ( !$res ) {
1638                         $this->installPrint( db2_stmt_errormsg() );
1639                 }
1640                 return $res;
1641         }
1642
1643         /**
1644          * Prepare & execute an SQL statement, quoting and inserting arguments
1645          * in the appropriate places.
1646          * @param $query String
1647          * @param $args ...
1648          */
1649         public function safeQuery( $query, $args = null ) {
1650                 // copied verbatim from Database.php
1651                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1652                 if( !is_array( $args ) ) {
1653                         # Pull the var args
1654                         $args = func_get_args();
1655                         array_shift( $args );
1656                 }
1657                 $retval = $this->execute( $prepared, $args );
1658                 $this->freePrepared( $prepared );
1659                 return $retval;
1660         }
1661
1662         /**
1663          * For faking prepared SQL statements on DBs that don't support
1664          * it directly.
1665          * @param $preparedQuery String: a 'preparable' SQL statement
1666          * @param $args Array of arguments to fill it with
1667          * @return String: executable statement
1668          */
1669         public function fillPrepared( $preparedQuery, $args ) {
1670                 reset( $args );
1671                 $this->preparedArgs =& $args;
1672
1673                 foreach ( $args as $i => $arg ) {
1674                         db2_bind_param( $preparedQuery, $i+1, $args[$i] );
1675                 }
1676
1677                 return $preparedQuery;
1678         }
1679
1680         /**
1681          * Switches module between regular and install modes
1682          */
1683         public function setMode( $mode ) {
1684                 $old = $this->mMode;
1685                 $this->mMode = $mode;
1686                 return $old;
1687         }
1688
1689         /**
1690          * Bitwise negation of a column or value in SQL
1691          * Same as (~field) in C
1692          * @param $field String
1693          * @return String
1694          */
1695         function bitNot( $field ) {
1696                 // expecting bit-fields smaller than 4bytes
1697                 return "BITNOT( $field )";
1698         }
1699
1700         /**
1701          * Bitwise AND of two columns or values in SQL
1702          * Same as (fieldLeft & fieldRight) in C
1703          * @param $fieldLeft String
1704          * @param $fieldRight String
1705          * @return String
1706          */
1707         function bitAnd( $fieldLeft, $fieldRight ) {
1708                 return "BITAND( $fieldLeft, $fieldRight )";
1709         }
1710
1711         /**
1712          * Bitwise OR of two columns or values in SQL
1713          * Same as (fieldLeft | fieldRight) in C
1714          * @param $fieldLeft String
1715          * @param $fieldRight String
1716          * @return String
1717          */
1718         function bitOr( $fieldLeft, $fieldRight ) {
1719                 return "BITOR( $fieldLeft, $fieldRight )";
1720         }
1721 }
1722
1723 class IBM_DB2Helper {
1724         public static function makeArray( $maybeArray ) {
1725                 if ( !is_array( $maybeArray ) ) {
1726                         return array( $maybeArray );
1727                 }
1728
1729                 return $maybeArray;
1730         }
1731 }