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          * Create tables, stored procedures, and so on
 593          */
 594         public function setup_database() {
 595                 try {
 596                         // TODO: switch to root login if available
 597
 598                         // Switch into the correct namespace
 599                         $this->applySchema();
 600                         $this->begin();
 601
 602                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 603                         if ( $res !== true ) {
 604                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 605                         } else {
 606                                 print ' done</li>';
 607                         }
 608                         $res = $this->sourceFile( "../maintenance/ibm_db2/foreignkeys.sql" );
 609                         if ( $res !== true ) {
 610                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 611                         } else {
 612                                 print '<li>Foreign keys done</li>';
 613                         }
 614                         $res = null;
 615
 616                         // TODO: populate interwiki links
 617
 618                         if ( $this->lastError() ) {
 619                                 $this->installPrint(
 620                                         'Errors encountered during table creation -- rolled back' );
 621                                 $this->installPrint( 'Please install again' );
 622                                 $this->rollback();
 623                         } else {
 624                                 $this->commit();
 625                         }
 626                 } catch ( MWException $mwe ) {
 627                         print "<br><pre>$mwe</pre><br>";
 628                 }
 629         }
 630
 631         /**
 632          * Escapes strings
 633          * Doesn't escape numbers
 634          *
 635          * @param $s String: string to escape
 636          * @return escaped string
 637          */
 638         public function addQuotes( $s ) {
 639                 //$this->installPrint( "DB2::addQuotes( $s )\n" );
 640                 if ( is_null( $s ) ) {
 641                         return 'NULL';
 642                 } elseif ( $s instanceof Blob ) {
 643                         return "'" . $s->fetch( $s ) . "'";
 644                 } elseif ( $s instanceof IBM_DB2Blob ) {
 645                         return "'" . $this->decodeBlob( $s ) . "'";
 646                 }
 647                 $s = $this->strencode( $s );
 648                 if ( is_numeric( $s ) ) {
 649                         return $s;
 650                 } else {
 651                         return "'$s'";
 652                 }
 653         }
 654
 655         /**
 656          * Verifies that a DB2 column/field type is numeric
 657          *
 658          * @param $type String: DB2 column type
 659          * @return Boolean: true if numeric
 660          */
 661         public function is_numeric_type( $type ) {
 662                 switch ( strtoupper( $type ) ) {
 663                         case 'SMALLINT':
 664                         case 'INTEGER':
 665                         case 'INT':
 666                         case 'BIGINT':
 667                         case 'DECIMAL':
 668                         case 'REAL':
 669                         case 'DOUBLE':
 670                         case 'DECFLOAT':
 671                                 return true;
 672                 }
 673                 return false;
 674         }
 675
 676         /**
 677          * Alias for addQuotes()
 678          * @param $s String: string to escape
 679          * @return escaped string
 680          */
 681         public function strencode( $s ) {
 682                 // Bloody useless function
 683                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 684                 //  But also necessary
 685                 $s = db2_escape_string( $s );
 686                 // Wide characters are evil -- some of them look like '
 687                 $s = utf8_encode( $s );
 688                 // Fix its stupidity
 689                 $from = array(  "\\\\", "\\'",  '\\n',  '\\t',  '\\"',  '\\r' );
 690                 $to = array(            "\\",           "''",           "\n",           "\t",           '"',            "\r" );
 691                 $s = str_replace( $from, $to, $s ); // DB2 expects '', not \' escaping
 692                 return $s;
 693         }
 694
 695         /**
 696          * Switch into the database schema
 697          */
 698         protected function applySchema() {
 699                 if ( !( $this->mSchemaSet ) ) {
 700                         $this->mSchemaSet = true;
 701                         $this->begin();
 702                         $this->doQuery( "SET SCHEMA = $this->mSchema" );
 703                         $this->commit();
 704                 }
 705         }
 706
 707         /**
 708          * Start a transaction (mandatory)
 709          */
 710         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 711                 // BEGIN is implicit for DB2
 712                 // However, it requires that AutoCommit be off.
 713
 714                 // Some MediaWiki code is still transaction-less (?).
 715                 // The strategy is to keep AutoCommit on for that code
 716                 //  but switch it off whenever a transaction is begun.
 717                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_OFF );
 718
 719                 $this->mTrxLevel = 1;
 720         }
 721
 722         /**
 723          * End a transaction
 724          * Must have a preceding begin()
 725          */
 726         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 727                 db2_commit( $this->mConn );
 728
 729                 // Some MediaWiki code is still transaction-less (?).
 730                 // The strategy is to keep AutoCommit on for that code
 731                 //  but switch it off whenever a transaction is begun.
 732                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 733
 734                 $this->mTrxLevel = 0;
 735         }
 736
 737         /**
 738          * Cancel a transaction
 739          */
 740         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 741                 db2_rollback( $this->mConn );
 742                 // turn auto-commit back on
 743                 // not sure if this is appropriate
 744                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 745                 $this->mTrxLevel = 0;
 746         }
 747
 748         /**
 749          * Makes an encoded list of strings from an array
 750          * $mode:
 751          *   LIST_COMMA         - comma separated, no field names
 752          *   LIST_AND           - ANDed WHERE clause (without the WHERE)
 753          *   LIST_OR            - ORed WHERE clause (without the WHERE)
 754          *   LIST_SET           - comma separated with field names, like a SET clause
 755          *   LIST_NAMES         - comma separated field names
 756          *   LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 757          */
 758         function makeList( $a, $mode = LIST_COMMA ) {
 759                 if ( !is_array( $a ) ) {
 760                         throw new DBUnexpectedError( $this,
 761                                 'DatabaseBase::makeList called with incorrect parameters' );
 762                 }
 763
 764                 // if this is for a prepared UPDATE statement
 765                 // (this should be promoted to the parent class
 766                 //  once other databases use prepared statements)
 767                 if ( $mode == LIST_SET_PREPARED ) {
 768                         $first = true;
 769                         $list = '';
 770                         foreach ( $a as $field => $value ) {
 771                                 if ( !$first ) {
 772                                         $list .= ", $field = ?";
 773                                 } else {
 774                                         $list .= "$field = ?";
 775                                         $first = false;
 776                                 }
 777                         }
 778                         $list .= '';
 779
 780                         return $list;
 781                 }
 782
 783                 // otherwise, call the usual function
 784                 return parent::makeList( $a, $mode );
 785         }
 786
 787         /**
 788          * Construct a LIMIT query with optional offset
 789          * This is used for query pages
 790          *
 791          * @param $sql string SQL query we will append the limit too
 792          * @param $limit integer the SQL limit
 793          * @param $offset integer the SQL offset (default false)
 794          */
 795         public function limitResult( $sql, $limit, $offset=false ) {
 796                 if( !is_numeric( $limit ) ) {
 797                         throw new DBUnexpectedError( $this,
 798                                 "Invalid non-numeric limit passed to limitResult()\n" );
 799                 }
 800                 if( $offset ) {
 801                         if ( stripos( $sql, 'where' ) === false ) {
 802                                 return "$sql AND ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 803                         } else {
 804                                 return "$sql WHERE ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 805                         }
 806                 }
 807                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 808         }
 809
 810         /**
 811          * Handle reserved keyword replacement in table names
 812          *
 813          * @param $name Object
 814          * @return String
 815          */
 816         public function tableName( $name ) {
 817                 // we want maximum compatibility with MySQL schema
 818                 return $name;
 819         }
 820
 821         /**
 822          * Generates a timestamp in an insertable format
 823          *
 824          * @param $ts timestamp
 825          * @return String: timestamp value
 826          */
 827         public function timestamp( $ts = 0 ) {
 828                 // TS_MW cannot be easily distinguished from an integer
 829                 return wfTimestamp( TS_DB2, $ts );
 830         }
 831
 832         /**
 833          * Return the next in a sequence, save the value for retrieval via insertId()
 834          * @param $seqName String: name of a defined sequence in the database
 835          * @return next value in that sequence
 836          */
 837         public function nextSequenceValue( $seqName ) {
 838                 // Not using sequences in the primary schema to allow for easier migration
 839                 //  from MySQL
 840                 // Emulating MySQL behaviour of using NULL to signal that sequences
 841                 // aren't used
 842                 /*
 843                 $safeseq = preg_replace( "/'/", "''", $seqName );
 844                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 845                 $row = $this->fetchRow( $res );
 846                 $this->mInsertId = $row[0];
 847                 return $this->mInsertId;
 848                 */
 849                 return null;
 850         }
 851
 852         /**
 853          * This must be called after nextSequenceVal
 854          * @return Last sequence value used as a primary key
 855          */
 856         public function insertId() {
 857                 return $this->mInsertId;
 858         }
 859
 860         /**
 861          * Updates the mInsertId property with the value of the last insert
 862          *  into a generated column
 863          *
 864          * @param $table      String: sanitized table name
 865          * @param $primaryKey Mixed: string name of the primary key
 866          * @param $stmt       Resource: prepared statement resource
 867          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
 868          */
 869         private function calcInsertId( $table, $primaryKey, $stmt ) {
 870                 if ( $primaryKey ) {
 871                         $this->mInsertId = db2_last_insert_id( $this->mConn );
 872                 }
 873         }
 874
 875         /**
 876          * INSERT wrapper, inserts an array into a table
 877          *
 878          * $args may be a single associative array, or an array of arrays
 879          *  with numeric keys, for multi-row insert
 880          *
 881          * @param $table   String: Name of the table to insert to.
 882          * @param $args    Array: Items to insert into the table.
 883          * @param $fname   String: Name of the function, for profiling
 884          * @param $options String or Array. Valid options: IGNORE
 885          *
 886          * @return bool Success of insert operation. IGNORE always returns true.
 887          */
 888         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert',
 889                 $options = array() )
 890         {
 891                 if ( !count( $args ) ) {
 892                         return true;
 893                 }
 894                 // get database-specific table name (not used)
 895                 $table = $this->tableName( $table );
 896                 // format options as an array
 897                 $options = IBM_DB2Helper::makeArray( $options );
 898                 // format args as an array of arrays
 899                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
 900                         $args = array( $args );
 901                 }
 902
 903                 // prevent insertion of NULL into primary key columns
 904                 list( $args, $primaryKeys ) = $this->removeNullPrimaryKeys( $table, $args );
 905                 // if there's only one primary key
 906                 // we'll be able to read its value after insertion
 907                 $primaryKey = false;
 908                 if ( count( $primaryKeys ) == 1 ) {
 909                         $primaryKey = $primaryKeys[0];
 910                 }
 911
 912                 // get column names
 913                 $keys = array_keys( $args[0] );
 914                 $key_count = count( $keys );
 915
 916                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 917                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
 918
 919                 // assume success
 920                 $res = true;
 921                 // If we are not in a transaction, we need to be for savepoint trickery
 922                 if ( !$this->mTrxLevel ) {
 923                         $this->begin();
 924                 }
 925
 926                 $sql = "INSERT INTO $table ( " . implode( ',', $keys ) . ' ) VALUES ';
 927                 if ( $key_count == 1 ) {
 928                         $sql .= '( ? )';
 929                 } else {
 930                         $sql .= '( ?' . str_repeat( ',?', $key_count-1 ) . ' )';
 931                 }
 932                 //$this->installPrint( "Preparing the following SQL:" );
 933                 //$this->installPrint( "$sql" );
 934                 //$this->installPrint( print_r( $args, true ));
 935                 $stmt = $this->prepare( $sql );
 936
 937                 // start a transaction/enter transaction mode
 938                 $this->begin();
 939
 940                 if ( !$ignore ) {
 941                         //$first = true;
 942                         foreach ( $args as $row ) {
 943                                 //$this->installPrint( "Inserting " . print_r( $row, true ));
 944                                 // insert each row into the database
 945                                 $res = $res & $this->execute( $stmt, $row );
 946                                 if ( !$res ) {
 947                                         $this->installPrint( 'Last error:' );
 948                                         $this->installPrint( $this->lastError() );
 949                                 }
 950                                 // get the last inserted value into a generated column
 951                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 952                         }
 953                 } else {
 954                         $olde = error_reporting( 0 );
 955                         // For future use, we may want to track the number of actual inserts
 956                         // Right now, insert (all writes) simply return true/false
 957                         $numrowsinserted = 0;
 958
 959                         // always return true
 960                         $res = true;
 961
 962                         foreach ( $args as $row ) {
 963                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
 964                                 db2_exec( $this->mConn, $overhead, $this->mStmtOptions );
 965
 966                                 $this->execute( $stmt, $row );
 967
 968                                 if ( !$res2 ) {
 969                                         $this->installPrint( 'Last error:' );
 970                                         $this->installPrint( $this->lastError() );
 971                                 }
 972                                 // get the last inserted value into a generated column
 973                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 974
 975                                 $errNum = $this->lastErrno();
 976                                 if ( $errNum ) {
 977                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore",
 978                                                 $this->mStmtOptions );
 979                                 } else {
 980                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore",
 981                                                 $this->mStmtOptions );
 982                                         $numrowsinserted++;
 983                                 }
 984                         }
 985
 986                         $olde = error_reporting( $olde );
 987                         // Set the affected row count for the whole operation
 988                         $this->mAffectedRows = $numrowsinserted;
 989                 }
 990                 // commit either way
 991                 $this->commit();
 992                 $this->freePrepared( $stmt );
 993
 994                 return $res;
 995         }
 996
 997         /**
 998          * Given a table name and a hash of columns with values
 999          * Removes primary key columns from the hash where the value is NULL
1000          *
1001          * @param $table String: name of the table
1002          * @param $args Array of hashes of column names with values
1003          * @return Array: tuple( filtered array of columns, array of primary keys )
1004          */
1005         private function removeNullPrimaryKeys( $table, $args ) {
1006                 $schema = $this->mSchema;
1007                 // find out the primary keys
1008                 $keyres = db2_primary_keys( $this->mConn, null, strtoupper( $schema ),
1009                         strtoupper( $table )
1010                 );
1011                 $keys = array();
1012                 for (
1013                         $row = $this->fetchObject( $keyres );
1014                         $row != null;
1015                         $row = $this->fetchObject( $keyres )
1016                 )
1017                 {
1018                         $keys[] = strtolower( $row->column_name );
1019                 }
1020                 // remove primary keys
1021                 foreach ( $args as $ai => $row ) {
1022                         foreach ( $keys as $ki => $key ) {
1023                                 if ( $row[$key] == null ) {
1024                                         unset( $row[$key] );
1025                                 }
1026                         }
1027                         $args[$ai] = $row;
1028                 }
1029                 // return modified hash
1030                 return array( $args, $keys );
1031         }
1032
1033         /**
1034          * UPDATE wrapper, takes a condition array and a SET array
1035          *
1036          * @param $table  String: The table to UPDATE
1037          * @param $values An array of values to SET
1038          * @param $conds  An array of conditions ( WHERE ). Use '*' to update all rows.
1039          * @param $fname  String: The Class::Function calling this function
1040          *                ( for the log )
1041          * @param $options An array of UPDATE options, can be one or
1042          *                 more of IGNORE, LOW_PRIORITY
1043          * @return Boolean
1044          */
1045         public function update( $table, $values, $conds, $fname = 'Database::update',
1046                 $options = array() )
1047         {
1048                 $table = $this->tableName( $table );
1049                 $opts = $this->makeUpdateOptions( $options );
1050                 $sql = "UPDATE $opts $table SET "
1051                         . $this->makeList( $values, LIST_SET_PREPARED );
1052                 if ( $conds != '*' ) {
1053                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1054                 }
1055                 $stmt = $this->prepare( $sql );
1056                 $this->installPrint( 'UPDATE: ' . print_r( $values, true ) );
1057                 // assuming for now that an array with string keys will work
1058                 // if not, convert to simple array first
1059                 $result = $this->execute( $stmt, $values );
1060                 $this->freePrepared( $stmt );
1061
1062                 return $result;
1063         }
1064
1065         /**
1066          * DELETE query wrapper
1067          *
1068          * Use $conds == "*" to delete all rows
1069          */
1070         public function delete( $table, $conds, $fname = 'Database::delete' ) {
1071                 if ( !$conds ) {
1072                         throw new DBUnexpectedError( $this,
1073                         'Database::delete() called with no conditions' );
1074                 }
1075                 $table = $this->tableName( $table );
1076                 $sql = "DELETE FROM $table";
1077                 if ( $conds != '*' ) {
1078                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1079                 }
1080                 $result = $this->query( $sql, $fname );
1081
1082                 return $result;
1083         }
1084
1085         /**
1086          * Returns the number of rows affected by the last query or 0
1087          * @return Integer: the number of rows affected by the last query
1088          */
1089         public function affectedRows() {
1090                 if ( !is_null( $this->mAffectedRows ) ) {
1091                         // Forced result for simulated queries
1092                         return $this->mAffectedRows;
1093                 }
1094                 if( empty( $this->mLastResult ) ) {
1095                         return 0;
1096                 }
1097                 return db2_num_rows( $this->mLastResult );
1098         }
1099
1100         /**
1101          * Simulates REPLACE with a DELETE followed by INSERT
1102          * @param $table Object
1103          * @param $uniqueIndexes Array consisting of indexes and arrays of indexes
1104          * @param $rows Array: rows to insert
1105          * @param $fname String: name of the function for profiling
1106          * @return nothing
1107          */
1108         function replace( $table, $uniqueIndexes, $rows,
1109                 $fname = 'DatabaseIbm_db2::replace' )
1110         {
1111                 $table = $this->tableName( $table );
1112
1113                 if ( count( $rows )==0 ) {
1114                         return;
1115                 }
1116
1117                 # Single row case
1118                 if ( !is_array( reset( $rows ) ) ) {
1119                         $rows = array( $rows );
1120                 }
1121
1122                 foreach( $rows as $row ) {
1123                         # Delete rows which collide
1124                         if ( $uniqueIndexes ) {
1125                                 $sql = "DELETE FROM $table WHERE ";
1126                                 $first = true;
1127                                 foreach ( $uniqueIndexes as $index ) {
1128                                         if ( $first ) {
1129                                                 $first = false;
1130                                                 $sql .= '( ';
1131                                         } else {
1132                                                 $sql .= ' ) OR ( ';
1133                                         }
1134                                         if ( is_array( $index ) ) {
1135                                                 $first2 = true;
1136                                                 foreach ( $index as $col ) {
1137                                                         if ( $first2 ) {
1138                                                                 $first2 = false;
1139                                                         } else {
1140                                                                 $sql .= ' AND ';
1141                                                         }
1142                                                         $sql .= $col . '=' . $this->addQuotes( $row[$col] );
1143                                                 }
1144                                         } else {
1145                                                 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
1146                                         }
1147                                 }
1148                                 $sql .= ' )';
1149                                 $this->query( $sql, $fname );
1150                         }
1151
1152                         # Now insert the row
1153                         $sql = "INSERT INTO $table ( "
1154                                 . $this->makeList( array_keys( $row ), LIST_NAMES )
1155                                 .' ) VALUES ( ' . $this->makeList( $row, LIST_COMMA ) . ' )';
1156                         $this->query( $sql, $fname );
1157                 }
1158         }
1159
1160         /**
1161          * Returns the number of rows in the result set
1162          * Has to be called right after the corresponding select query
1163          * @param $res Object result set
1164          * @return Integer: number of rows
1165          */
1166         public function numRows( $res ) {
1167                 if ( $res instanceof ResultWrapper ) {
1168                         $res = $res->result;
1169                 }
1170                 if ( $this->mNumRows ) {
1171                         return $this->mNumRows;
1172                 } else {
1173                         return 0;
1174                 }
1175         }
1176
1177         /**
1178          * Moves the row pointer of the result set
1179          * @param $res Object: result set
1180          * @param $row Integer: row number
1181          * @return success or failure
1182          */
1183         public function dataSeek( $res, $row ) {
1184                 if ( $res instanceof ResultWrapper ) {
1185                         $res = $res->result;
1186                 }
1187                 return db2_fetch_row( $res, $row );
1188         }
1189
1190         ###
1191         # Fix notices in Block.php
1192         ###
1193
1194         /**
1195          * Frees memory associated with a statement resource
1196          * @param $res Object: statement resource to free
1197          * @return Boolean success or failure
1198          */
1199         public function freeResult( $res ) {
1200                 if ( $res instanceof ResultWrapper ) {
1201                         $res = $res->result;
1202                 }
1203                 if ( !@db2_free_result( $res ) ) {
1204                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
1205                 }
1206         }
1207
1208         /**
1209          * Returns the number of columns in a resource
1210          * @param $res Object: statement resource
1211          * @return Number of fields/columns in resource
1212          */
1213         public function numFields( $res ) {
1214                 if ( $res instanceof ResultWrapper ) {
1215                         $res = $res->result;
1216                 }
1217                 return db2_num_fields( $res );
1218         }
1219
1220         /**
1221          * Returns the nth column name
1222          * @param $res Object: statement resource
1223          * @param $n Integer: Index of field or column
1224          * @return String name of nth column
1225          */
1226         public function fieldName( $res, $n ) {
1227                 if ( $res instanceof ResultWrapper ) {
1228                         $res = $res->result;
1229                 }
1230                 return db2_field_name( $res, $n );
1231         }
1232
1233         /**
1234          * SELECT wrapper
1235          *
1236          * @param $table   Array or string, table name(s) (prefix auto-added)
1237          * @param $vars    Array or string, field name(s) to be retrieved
1238          * @param $conds   Array or string, condition(s) for WHERE
1239          * @param $fname   String: calling function name (use __METHOD__)
1240          *                 for logs/profiling
1241          * @param $options Associative array of options
1242          *                 (e.g. array('GROUP BY' => 'page_title')),
1243          *                 see Database::makeSelectOptions code for list of
1244          *                 supported stuff
1245          * @param $join_conds Associative array of table join conditions (optional)
1246          *                    (e.g. array( 'page' => array('LEFT JOIN',
1247          *                    'page_latest=rev_id') )
1248          * @return Mixed: database result resource for fetch functions or false
1249          *                 on failure
1250          */
1251         public function select( $table, $vars, $conds = '', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1252         {
1253                 $res = parent::select( $table, $vars, $conds, $fname, $options,
1254                         $join_conds );
1255
1256                 // We must adjust for offset
1257                 if ( isset( $options['LIMIT'] ) ) {
1258                         if ( isset ( $options['OFFSET'] ) ) {
1259                                 $limit = $options['LIMIT'];
1260                                 $offset = $options['OFFSET'];
1261                         }
1262                 }
1263
1264
1265                 // DB2 does not have a proper num_rows() function yet, so we must emulate
1266                 // DB2 9.5.4 and the corresponding ibm_db2 driver will introduce
1267                 //  a working one
1268                 // TODO: Yay!
1269
1270                 // we want the count
1271                 $vars2 = array( 'count( * ) as num_rows' );
1272                 // respecting just the limit option
1273                 $options2 = array();
1274                 if ( isset( $options['LIMIT'] ) ) {
1275                         $options2['LIMIT'] = $options['LIMIT'];
1276                 }
1277                 // but don't try to emulate for GROUP BY
1278                 if ( isset( $options['GROUP BY'] ) ) {
1279                         return $res;
1280                 }
1281
1282                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2,
1283                         $join_conds );
1284                 $obj = $this->fetchObject( $res2 );
1285                 $this->mNumRows = $obj->num_rows;
1286
1287                 return $res;
1288         }
1289
1290         /**
1291          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1292          * Has limited support for per-column options (colnum => 'DISTINCT')
1293          *
1294          * @private
1295          *
1296          * @param $options Associative array of options to be turned into
1297          *              an SQL query, valid keys are listed in the function.
1298          * @return Array
1299          */
1300         function makeSelectOptions( $options ) {
1301                 $preLimitTail = $postLimitTail = '';
1302                 $startOpts = '';
1303
1304                 $noKeyOptions = array();
1305                 foreach ( $options as $key => $option ) {
1306                         if ( is_numeric( $key ) ) {
1307                                 $noKeyOptions[$option] = true;
1308                         }
1309                 }
1310
1311                 if ( isset( $options['GROUP BY'] ) ) {
1312                         $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1313                 }
1314                 if ( isset( $options['HAVING'] ) ) {
1315                         $preLimitTail .= " HAVING {$options['HAVING']}";
1316                 }
1317                 if ( isset( $options['ORDER BY'] ) ) {
1318                         $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1319                 }
1320
1321                 if ( isset( $noKeyOptions['DISTINCT'] )
1322                         || isset( $noKeyOptions['DISTINCTROW'] ) )
1323                 {
1324                         $startOpts .= 'DISTINCT';
1325                 }
1326
1327                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1328         }
1329
1330         /**
1331          * Returns link to IBM DB2 free download
1332          * @return String: wikitext of a link to the server software's web site
1333          */
1334         public static function getSoftwareLink() {
1335                 return '[http://www.ibm.com/db2/express/ IBM DB2]';
1336         }
1337
1338         /**
1339          * Get search engine class. All subclasses of this
1340          * need to implement this if they wish to use searching.
1341          *
1342          * @return String
1343          */
1344         public function getSearchEngine() {
1345                 return 'SearchIBM_DB2';
1346         }
1347
1348         /**
1349          * Did the last database access fail because of deadlock?
1350          * @return Boolean
1351          */
1352         public function wasDeadlock() {
1353                 // get SQLSTATE
1354                 $err = $this->lastErrno();
1355                 switch( $err ) {
1356                         // This is literal port of the MySQL logic and may be wrong for DB2
1357                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1358                         case '57011':   // sql0904n, Resource unavailable, no rollback
1359                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1360                         $this->installPrint( "In a deadlock because of SQLSTATE $err" );
1361                         return true;
1362                 }
1363                 return false;
1364         }
1365
1366         /**
1367          * Ping the server and try to reconnect if it there is no connection
1368          * The connection may be closed and reopened while this happens
1369          * @return Boolean: whether the connection exists
1370          */
1371         public function ping() {
1372                 // db2_ping() doesn't exist
1373                 // Emulate
1374                 $this->close();
1375                 $this->mConn = $this->openUncataloged( $this->mDBName, $this->mUser,
1376                         $this->mPassword, $this->mServer, $this->mPort );
1377
1378                 return false;
1379         }
1380         ######################################
1381         # Unimplemented and not applicable
1382         ######################################
1383         /**
1384          * Not implemented
1385          * @return string ''
1386          */
1387         public function getStatus( $which = '%' ) {
1388                 $this->installPrint( 'Not implemented for DB2: getStatus()' );
1389                 return '';
1390         }
1391         /**
1392          * Not implemented
1393          * @return string $sql
1394          */
1395         public function limitResultForUpdate( $sql, $num ) {
1396                 $this->installPrint( 'Not implemented for DB2: limitResultForUpdate()' );
1397                 return $sql;
1398         }
1399
1400         /**
1401          * Only useful with fake prepare like in base Database class
1402          * @return      string
1403          */
1404         public function fillPreparedArg( $matches ) {
1405                 $this->installPrint( 'Not useful for DB2: fillPreparedArg()' );
1406                 return '';
1407         }
1408
1409         ######################################
1410         # Reflection
1411         ######################################
1412
1413         /**
1414          * Returns information about an index
1415          * If errors are explicitly ignored, returns NULL on failure
1416          * @param $table String: table name
1417          * @param $index String: index name
1418          * @param $fname String: function name for logging and profiling
1419          * @return Object query row in object form
1420          */
1421         public function indexInfo( $table, $index,
1422                 $fname = 'DatabaseIbm_db2::indexExists' )
1423         {
1424                 $table = $this->tableName( $table );
1425                 $sql = <<<SQL
1426 SELECT name as indexname
1427 FROM sysibm.sysindexes si
1428 WHERE si.name='$index' AND si.tbname='$table'
1429 AND sc.tbcreator='$this->mSchema'
1430 SQL;
1431                 $res = $this->query( $sql, $fname );
1432                 if ( !$res ) {
1433                         return null;
1434                 }
1435                 $row = $this->fetchObject( $res );
1436                 if ( $row != null ) {
1437                         return $row;
1438                 } else {
1439                         return false;
1440                 }
1441         }
1442
1443         /**
1444          * Returns an information object on a table column
1445          * @param $table String: table name
1446          * @param $field String: column name
1447          * @return IBM_DB2Field
1448          */
1449         public function fieldInfo( $table, $field ) {
1450                 return IBM_DB2Field::fromText( $this, $table, $field );
1451         }
1452
1453         /**
1454          * db2_field_type() wrapper
1455          * @param $res Object: result of executed statement
1456          * @param $index Mixed: number or name of the column
1457          * @return String column type
1458          */
1459         public function fieldType( $res, $index ) {
1460                 if ( $res instanceof ResultWrapper ) {
1461                         $res = $res->result;
1462                 }
1463                 return db2_field_type( $res, $index );
1464         }
1465
1466         /**
1467          * Verifies that an index was created as unique
1468          * @param $table String: table name
1469          * @param $index String: index name
1470          * @param $fname function name for profiling
1471          * @return Bool
1472          */
1473         public function indexUnique ( $table, $index,
1474                 $fname = 'Database::indexUnique' )
1475         {
1476                 $table = $this->tableName( $table );
1477                 $sql = <<<SQL
1478 SELECT si.name as indexname
1479 FROM sysibm.sysindexes si
1480 WHERE si.name='$index' AND si.tbname='$table'
1481 AND sc.tbcreator='$this->mSchema'
1482 AND si.uniquerule IN ( 'U', 'P' )
1483 SQL;
1484                 $res = $this->query( $sql, $fname );
1485                 if ( !$res ) {
1486                         return null;
1487                 }
1488                 if ( $this->fetchObject( $res ) ) {
1489                         return true;
1490                 }
1491                 return false;
1492
1493         }
1494
1495         /**
1496          * Returns the size of a text field, or -1 for "unlimited"
1497          * @param $table String: table name
1498          * @param $field String: column name
1499          * @return Integer: length or -1 for unlimited
1500          */
1501         public function textFieldSize( $table, $field ) {
1502                 $table = $this->tableName( $table );
1503                 $sql = <<<SQL
1504 SELECT length as size
1505 FROM sysibm.syscolumns sc
1506 WHERE sc.name='$field' AND sc.tbname='$table'
1507 AND sc.tbcreator='$this->mSchema'
1508 SQL;
1509                 $res = $this->query( $sql );
1510                 $row = $this->fetchObject( $res );
1511                 $size = $row->size;
1512                 return $size;
1513         }
1514
1515         /**
1516          * DELETE where the condition is a join
1517          * @param $delTable String: deleting from this table
1518          * @param $joinTable String: using data from this table
1519          * @param $delVar String: variable in deleteable table
1520          * @param $joinVar String: variable in data table
1521          * @param $conds Array: conditionals for join table
1522          * @param $fname String: function name for profiling
1523          */
1524         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar,
1525                 $conds, $fname = "DatabaseIbm_db2::deleteJoin" )
1526         {
1527                 if ( !$conds ) {
1528                         throw new DBUnexpectedError( $this,
1529                         'Database::deleteJoin() called with empty $conds' );
1530                 }
1531
1532                 $delTable = $this->tableName( $delTable );
1533                 $joinTable = $this->tableName( $joinTable );
1534                 $sql = <<<SQL
1535 DELETE FROM $delTable
1536 WHERE $delVar IN (
1537   SELECT $joinVar FROM $joinTable
1538
1539 SQL;
1540                 if ( $conds != '*' ) {
1541                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1542                 }
1543                 $sql .= ' )';
1544
1545                 $this->query( $sql, $fname );
1546         }
1547
1548         /**
1549          * Description is left as an exercise for the reader
1550          * @param $b Mixed: data to be encoded
1551          * @return IBM_DB2Blob
1552          */
1553         public function encodeBlob( $b ) {
1554                 return new IBM_DB2Blob( $b );
1555         }
1556
1557         /**
1558          * Description is left as an exercise for the reader
1559          * @param $b IBM_DB2Blob: data to be decoded
1560          * @return mixed
1561          */
1562         public function decodeBlob( $b ) {
1563                 return "$b";
1564         }
1565
1566         /**
1567          * Convert into a list of string being concatenated
1568          * @param $stringList Array: strings that need to be joined together
1569          *                    by the SQL engine
1570          * @return String: joined by the concatenation operator
1571          */
1572         public function buildConcat( $stringList ) {
1573                 // || is equivalent to CONCAT
1574                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1575                 return implode( ' || ', $stringList );
1576         }
1577
1578         /**
1579          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1580          * @param $column String: name of timestamp column
1581          * @return String: SQL code
1582          */
1583         public function extractUnixEpoch( $column ) {
1584                 // TODO
1585                 // see SpecialAncientpages
1586         }
1587
1588         ######################################
1589         # Prepared statements
1590         ######################################
1591
1592         /**
1593          * Intended to be compatible with the PEAR::DB wrapper functions.
1594          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1595          *
1596          * ? = scalar value, quoted as necessary
1597          * ! = raw SQL bit (a function for instance)
1598          * & = filename; reads the file and inserts as a blob
1599          *     (we don't use this though...)
1600          * @param $sql String: SQL statement with appropriate markers
1601          * @param $func String: Name of the function, for profiling
1602          * @return resource a prepared DB2 SQL statement
1603          */
1604         public function prepare( $sql, $func = 'DB2::prepare' ) {
1605                 $stmt = db2_prepare( $this->mConn, $sql, $this->mStmtOptions );
1606                 return $stmt;
1607         }
1608
1609         /**
1610          * Frees resources associated with a prepared statement
1611          * @return Boolean success or failure
1612          */
1613         public function freePrepared( $prepared ) {
1614                 return db2_free_stmt( $prepared );
1615         }
1616
1617         /**
1618          * Execute a prepared query with the various arguments
1619          * @param $prepared String: the prepared sql
1620          * @param $args Mixed: either an array here, or put scalars as varargs
1621          * @return Resource: results object
1622          */
1623         public function execute( $prepared, $args = null ) {
1624                 if( !is_array( $args ) ) {
1625                         # Pull the var args
1626                         $args = func_get_args();
1627                         array_shift( $args );
1628                 }
1629                 $res = db2_execute( $prepared, $args );
1630                 if ( !$res ) {
1631                         $this->installPrint( db2_stmt_errormsg() );
1632                 }
1633                 return $res;
1634         }
1635
1636         /**
1637          * Prepare & execute an SQL statement, quoting and inserting arguments
1638          * in the appropriate places.
1639          * @param $query String
1640          * @param $args ...
1641          */
1642         public function safeQuery( $query, $args = null ) {
1643                 // copied verbatim from Database.php
1644                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1645                 if( !is_array( $args ) ) {
1646                         # Pull the var args
1647                         $args = func_get_args();
1648                         array_shift( $args );
1649                 }
1650                 $retval = $this->execute( $prepared, $args );
1651                 $this->freePrepared( $prepared );
1652                 return $retval;
1653         }
1654
1655         /**
1656          * For faking prepared SQL statements on DBs that don't support
1657          * it directly.
1658          * @param $preparedQuery String: a 'preparable' SQL statement
1659          * @param $args Array of arguments to fill it with
1660          * @return String: executable statement
1661          */
1662         public function fillPrepared( $preparedQuery, $args ) {
1663                 reset( $args );
1664                 $this->preparedArgs =& $args;
1665
1666                 foreach ( $args as $i => $arg ) {
1667                         db2_bind_param( $preparedQuery, $i+1, $args[$i] );
1668                 }
1669
1670                 return $preparedQuery;
1671         }
1672
1673         /**
1674          * Switches module between regular and install modes
1675          */
1676         public function setMode( $mode ) {
1677                 $old = $this->mMode;
1678                 $this->mMode = $mode;
1679                 return $old;
1680         }
1681
1682         /**
1683          * Bitwise negation of a column or value in SQL
1684          * Same as (~field) in C
1685          * @param $field String
1686          * @return String
1687          */
1688         function bitNot( $field ) {
1689                 // expecting bit-fields smaller than 4bytes
1690                 return "BITNOT( $field )";
1691         }
1692
1693         /**
1694          * Bitwise AND of two columns or values in SQL
1695          * Same as (fieldLeft & fieldRight) in C
1696          * @param $fieldLeft String
1697          * @param $fieldRight String
1698          * @return String
1699          */
1700         function bitAnd( $fieldLeft, $fieldRight ) {
1701                 return "BITAND( $fieldLeft, $fieldRight )";
1702         }
1703
1704         /**
1705          * Bitwise OR of two columns or values in SQL
1706          * Same as (fieldLeft | fieldRight) in C
1707          * @param $fieldLeft String
1708          * @param $fieldRight String
1709          * @return String
1710          */
1711         function bitOr( $fieldLeft, $fieldRight ) {
1712                 return "BITOR( $fieldLeft, $fieldRight )";
1713         }
1714 }
1715
1716 class IBM_DB2Helper {
1717         public static function makeArray( $maybeArray ) {
1718                 if ( !is_array( $maybeArray ) ) {
1719                         return array( $maybeArray );
1720                 }
1721
1722                 return $maybeArray;
1723         }
1724 }