includes/db/DatabaseIbm_db2.php

   1 <?php
   2 /**
   3  * This is the IBM DB2 database abstraction layer.
   4  * See maintenance/ibm_db2/README for development notes
   5  * and other specific information
   6  *
   7  * @file
   8  * @ingroup Database
   9  * @author leo.petr+mediawiki@gmail.com
  10  */
  11
  12 /**
  13  * This represents a column in a DB2 database
  14  * @ingroup Database
  15  */
  16 class IBM_DB2Field implements Field {
  17         private $name = '';
  18         private $tablename = '';
  19         private $type = '';
  20         private $nullable = false;
  21         private $max_length = 0;
  22
  23         /**
  24          * Builder method for the class
  25          * @param $db DatabaseIbm_db2: Database interface
  26          * @param $table String: table name
  27          * @param $field String: column name
  28          * @return IBM_DB2Field
  29          */
  30         static function fromText( $db, $table, $field ) {
  31                 global $wgDBmwschema;
  32
  33                 $q = <<<SQL
  34 SELECT
  35 lcase( coltype ) AS typname,
  36 nulls AS attnotnull, length AS attlen
  37 FROM sysibm.syscolumns
  38 WHERE tbcreator=%s AND tbname=%s AND name=%s;
  39 SQL;
  40                 $res = $db->query(
  41                         sprintf( $q,
  42                                 $db->addQuotes( $wgDBmwschema ),
  43                                 $db->addQuotes( $table ),
  44                                 $db->addQuotes( $field )
  45                         )
  46                 );
  47                 $row = $db->fetchObject( $res );
  48                 if ( !$row ) {
  49                         return null;
  50                 }
  51                 $n = new IBM_DB2Field;
  52                 $n->type = $row->typname;
  53                 $n->nullable = ( $row->attnotnull == 'N' );
  54                 $n->name = $field;
  55                 $n->tablename = $table;
  56                 $n->max_length = $row->attlen;
  57                 return $n;
  58         }
  59         /**
  60          * Get column name
  61          * @return string column name
  62          */
  63         function name() { return $this->name; }
  64         /**
  65          * Get table name
  66          * @return string table name
  67          */
  68         function tableName() { return $this->tablename; }
  69         /**
  70          * Get column type
  71          * @return string column type
  72          */
  73         function type() { return $this->type; }
  74         /**
  75          * Can column be null?
  76          * @return bool true or false
  77          */
  78         function isNullable() { return $this->nullable; }
  79         /**
  80          * How much can you fit in the column per row?
  81          * @return int length
  82          */
  83         function maxLength() { return $this->max_length; }
  84 }
  85
  86 /**
  87  * Wrapper around binary large objects
  88  * @ingroup Database
  89  */
  90 class IBM_DB2Blob {
  91         private $mData;
  92
  93         public function __construct( $data ) {
  94                 $this->mData = $data;
  95         }
  96
  97         public function getData() {
  98                 return $this->mData;
  99         }
 100
 101         public function __toString() {
 102                 return $this->mData;
 103         }
 104 }
 105
 106 /**
 107  * Primary database interface
 108  * @ingroup Database
 109  */
 110 class DatabaseIbm_db2 extends DatabaseBase {
 111         /*
 112          * Inherited members
 113         protected $mLastQuery = '';
 114         protected $mPHPError = false;
 115
 116         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 117         protected $mOpened = false;
 118
 119         protected $mTablePrefix;
 120         protected $mFlags;
 121         protected $mTrxLevel = 0;
 122         protected $mErrorCount = 0;
 123         protected $mLBInfo = array();
 124         protected $mFakeSlaveLag = null, $mFakeMaster = false;
 125          *
 126          */
 127
 128         /** Database server port */
 129         protected $mPort = null;
 130         /** Schema for tables, stored procedures, triggers */
 131         protected $mSchema = null;
 132         /** Whether the schema has been applied in this session */
 133         protected $mSchemaSet = false;
 134         /** Result of last query */
 135         protected $mLastResult = null;
 136         /** Number of rows affected by last INSERT/UPDATE/DELETE */
 137         protected $mAffectedRows = null;
 138         /** Number of rows returned by last SELECT */
 139         protected $mNumRows = null;
 140
 141         /** Connection config options - see constructor */
 142         public $mConnOptions = array();
 143         /** Statement config options -- see constructor */
 144         public $mStmtOptions = array();
 145
 146         /** Default schema */
 147         const USE_GLOBAL = 'mediawiki';
 148
 149         /** Option that applies to nothing */
 150         const NONE_OPTION = 0x00;
 151         /** Option that applies to connection objects */
 152         const CONN_OPTION = 0x01;
 153         /** Option that applies to statement objects */
 154         const STMT_OPTION = 0x02;
 155
 156         /** Regular operation mode -- minimal debug messages */
 157         const REGULAR_MODE = 'regular';
 158         /** Installation mode -- lots of debug messages */
 159         const INSTALL_MODE = 'install';
 160
 161         /** Controls the level of debug message output */
 162         protected $mMode = self::REGULAR_MODE;
 163
 164         /** Last sequence value used for a primary key */
 165         protected $mInsertId = null;
 166
 167         ######################################
 168         # Getters and Setters
 169         ######################################
 170
 171         /**
 172          * Returns true if this database supports (and uses) cascading deletes
 173          */
 174         function cascadingDeletes() {
 175                 return true;
 176         }
 177
 178         /**
 179          * Returns true if this database supports (and uses) triggers (e.g. on the
 180          *  page table)
 181          */
 182         function cleanupTriggers() {
 183                 return true;
 184         }
 185
 186         /**
 187          * Returns true if this database is strict about what can be put into an
 188          *  IP field.
 189          * Specifically, it uses a NULL value instead of an empty string.
 190          */
 191         function strictIPs() {
 192                 return true;
 193         }
 194
 195         /**
 196          * Returns true if this database uses timestamps rather than integers
 197         */
 198         function realTimestamps() {
 199                 return true;
 200         }
 201
 202         /**
 203          * Returns true if this database does an implicit sort when doing GROUP BY
 204          */
 205         function implicitGroupby() {
 206                 return false;
 207         }
 208
 209         /**
 210          * Returns true if this database does an implicit order by when the column
 211          *  has an index
 212          * For example: SELECT page_title FROM page LIMIT 1
 213          */
 214         function implicitOrderby() {
 215                 return false;
 216         }
 217
 218         /**
 219          * Returns true if this database can do a native search on IP columns
 220          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 221          */
 222         function searchableIPs() {
 223                 return true;
 224         }
 225
 226         /**
 227          * Returns true if this database can use functional indexes
 228          */
 229         function functionalIndexes() {
 230                 return true;
 231         }
 232
 233         /**
 234          * Returns a unique string representing the wiki on the server
 235          */
 236         function getWikiID() {
 237                 if( $this->mSchema ) {
 238                         return "{$this->mDBname}-{$this->mSchema}";
 239                 } else {
 240                         return $this->mDBname;
 241                 }
 242         }
 243
 244         function getType() {
 245                 return 'ibm_db2';
 246         }
 247
 248         /**
 249          *
 250          * @param $server String: hostname of database server
 251          * @param $user String: username
 252          * @param $password String: password
 253          * @param $dbName String: database name on the server
 254          * @param $flags Integer: database behaviour flags (optional, unused)
 255          * @param $schema String
 256          */
 257         public function __construct( $server = false, $user = false,
 258                                                         $password = false,
 259                                                         $dbName = false, $flags = 0,
 260                                                         $schema = self::USE_GLOBAL )
 261         {
 262                 global $wgDBmwschema;
 263
 264                 if ( $schema == self::USE_GLOBAL ) {
 265                         $this->mSchema = $wgDBmwschema;
 266                 } else {
 267                         $this->mSchema = $schema;
 268                 }
 269
 270                 // configure the connection and statement objects
 271                 $this->setDB2Option( 'db2_attr_case', 'DB2_CASE_LOWER',
 272                         self::CONN_OPTION | self::STMT_OPTION );
 273                 $this->setDB2Option( 'deferred_prepare', 'DB2_DEFERRED_PREPARE_ON',
 274                         self::STMT_OPTION );
 275                 $this->setDB2Option( 'rowcount', 'DB2_ROWCOUNT_PREFETCH_ON',
 276                         self::STMT_OPTION );
 277
 278                 parent::__construct( $server, $user, $password, $dbName, DBO_TRX | $flags );
 279         }
 280
 281         /**
 282          * Enables options only if the ibm_db2 extension version supports them
 283          * @param $name String: name of the option in the options array
 284          * @param $const String: name of the constant holding the right option value
 285          * @param $type Integer: whether this is a Connection or Statement otion
 286          */
 287         private function setDB2Option( $name, $const, $type ) {
 288                 if ( defined( $const ) ) {
 289                         if ( $type & self::CONN_OPTION ) {
 290                                 $this->mConnOptions[$name] = constant( $const );
 291                         }
 292                         if ( $type & self::STMT_OPTION ) {
 293                                 $this->mStmtOptions[$name] = constant( $const );
 294                         }
 295                 } else {
 296                         $this->installPrint(
 297                                 "$const is not defined. ibm_db2 version is likely too low." );
 298                 }
 299         }
 300
 301         /**
 302          * Outputs debug information in the appropriate place
 303          * @param $string String: the relevant debug message
 304          */
 305         private function installPrint( $string ) {
 306                 wfDebug( "$string\n" );
 307                 if ( $this->mMode == self::INSTALL_MODE ) {
 308                         print "<li><pre>$string</pre></li>";
 309                         flush();
 310                 }
 311         }
 312
 313         /**
 314          * Opens a database connection and returns it
 315          * Closes any existing connection
 316          *
 317          * @param $server String: hostname
 318          * @param $user String
 319          * @param $password String
 320          * @param $dbName String: database name
 321          * @return a fresh connection
 322          */
 323         public function open( $server, $user, $password, $dbName ) {
 324                 // Load the port number
 325                 global $wgDBport;
 326                 wfProfileIn( __METHOD__ );
 327
 328                 // Load IBM DB2 driver if missing
 329                 wfDl( 'ibm_db2' );
 330
 331                 // Test for IBM DB2 support, to avoid suppressed fatal error
 332                 if ( !function_exists( 'db2_connect' ) ) {
 333                         $error = <<<ERROR
 334 DB2 functions missing, have you enabled the ibm_db2 extension for PHP?
 335
 336 ERROR;
 337                         $this->installPrint( $error );
 338                         $this->reportConnectionError( $error );
 339                 }
 340
 341                 if ( strlen( $user ) < 1 ) {
 342                         wfProfileOut( __METHOD__ );
 343                         return null;
 344                 }
 345
 346                 // Close existing connection
 347                 $this->close();
 348                 // Cache conn info
 349                 $this->mServer = $server;
 350                 $this->mPort = $port = $wgDBport;
 351                 $this->mUser = $user;
 352                 $this->mPassword = $password;
 353                 $this->mDBname = $dbName;
 354
 355                 $this->openUncataloged( $dbName, $user, $password, $server, $port );
 356
 357                 // Apply connection config
 358                 db2_set_option( $this->mConn, $this->mConnOptions, 1 );
 359                 // Some MediaWiki code is still transaction-less (?).
 360                 // The strategy is to keep AutoCommit on for that code
 361                 //  but switch it off whenever a transaction is begun.
 362                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 363
 364                 if ( !$this->mConn ) {
 365                         $this->installPrint( "DB connection error\n" );
 366                         $this->installPrint(
 367                                 "Server: $server, Database: $dbName, User: $user, Password: "
 368                                 . substr( $password, 0, 3 ) . "...\n" );
 369                         $this->installPrint( $this->lastError() . "\n" );
 370
 371                         wfProfileOut( __METHOD__ );
 372                         return null;
 373                 }
 374
 375                 $this->mOpened = true;
 376                 $this->applySchema();
 377
 378                 wfProfileOut( __METHOD__ );
 379                 return $this->mConn;
 380         }
 381
 382         /**
 383          * Opens a cataloged database connection, sets mConn
 384          */
 385         protected function openCataloged( $dbName, $user, $password ) {
 386                 @$this->mConn = db2_pconnect( $dbName, $user, $password );
 387         }
 388
 389         /**
 390          * Opens an uncataloged database connection, sets mConn
 391          */
 392         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 393         {
 394                 $str = "DRIVER={IBM DB2 ODBC DRIVER};";
 395                 $str .= "DATABASE=$dbName;";
 396                 $str .= "HOSTNAME=$server;";
 397                 // port was formerly validated to not be 0
 398                 $str .= "PORT=$port;";
 399                 $str .= "PROTOCOL=TCPIP;";
 400                 $str .= "UID=$user;";
 401                 $str .= "PWD=$password;";
 402
 403                 @$this->mConn = db2_pconnect( $str, $user, $password );
 404         }
 405
 406         /**
 407          * Closes a database connection, if it is open
 408          * Returns success, true if already closed
 409          */
 410         public function close() {
 411                 $this->mOpened = false;
 412                 if ( $this->mConn ) {
 413                         if ( $this->trxLevel() > 0 ) {
 414                                 $this->commit();
 415                         }
 416                         return db2_close( $this->mConn );
 417                 } else {
 418                         return true;
 419                 }
 420         }
 421
 422         /**
 423          * Retrieves the most current database error
 424          * Forces a database rollback
 425          */
 426         public function lastError() {
 427                 $connerr = db2_conn_errormsg();
 428                 if ( $connerr ) {
 429                         //$this->rollback();
 430                         return $connerr;
 431                 }
 432                 $stmterr = db2_stmt_errormsg();
 433                 if ( $stmterr ) {
 434                         //$this->rollback();
 435                         return $stmterr;
 436                 }
 437
 438                 return false;
 439         }
 440
 441         /**
 442          * Get the last error number
 443          * Return 0 if no error
 444          * @return integer
 445          */
 446         public function lastErrno() {
 447                 $connerr = db2_conn_error();
 448                 if ( $connerr ) {
 449                         return $connerr;
 450                 }
 451                 $stmterr = db2_stmt_error();
 452                 if ( $stmterr ) {
 453                         return $stmterr;
 454                 }
 455                 return 0;
 456         }
 457
 458         /**
 459          * Is a database connection open?
 460          * @return
 461          */
 462         public function isOpen() { return $this->mOpened; }
 463
 464         /**
 465          * The DBMS-dependent part of query()
 466          * @param  $sql String: SQL query.
 467          * @return object Result object for fetch functions or false on failure
 468          * @access private
 469          */
 470         /*private*/
 471         public function doQuery( $sql ) {
 472                 $this->applySchema();
 473
 474                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 475                 if( $ret == false ) {
 476                         $error = db2_stmt_errormsg();
 477                         $this->installPrint( "<pre>$sql</pre>" );
 478                         $this->installPrint( $error );
 479                         throw new DBUnexpectedError( $this, 'SQL error: '
 480                                 . htmlspecialchars( $error ) );
 481                 }
 482                 $this->mLastResult = $ret;
 483                 $this->mAffectedRows = null; // Not calculated until asked for
 484                 return $ret;
 485         }
 486
 487         /**
 488          * @return string Version information from the database
 489          */
 490         public function getServerVersion() {
 491                 $info = db2_server_info( $this->mConn );
 492                 return $info->DBMS_VER;
 493         }
 494
 495         /**
 496          * Queries whether a given table exists
 497          * @return boolean
 498          */
 499         public function tableExists( $table ) {
 500                 $schema = $this->mSchema;
 501                 $sql = <<< EOF
 502 SELECT COUNT( * ) FROM SYSIBM.SYSTABLES ST
 503 WHERE ST.NAME = '$table' AND ST.CREATOR = '$schema'
 504 EOF;
 505                 $res = $this->query( $sql );
 506                 if ( !$res ) {
 507                         return false;
 508                 }
 509
 510                 // If the table exists, there should be one of it
 511                 @$row = $this->fetchRow( $res );
 512                 $count = $row[0];
 513                 if ( $count == '1' || $count == 1 ) {
 514                         return true;
 515                 }
 516
 517                 return false;
 518         }
 519
 520         /**
 521          * Fetch the next row from the given result object, in object form.
 522          * Fields can be retrieved with $row->fieldname, with fields acting like
 523          * member variables.
 524          *
 525          * @param $res SQL result object as returned from Database::query(), etc.
 526          * @return DB2 row object
 527          * @throws DBUnexpectedError Thrown if the database returns an error
 528          */
 529         public function fetchObject( $res ) {
 530                 if ( $res instanceof ResultWrapper ) {
 531                         $res = $res->result;
 532                 }
 533                 @$row = db2_fetch_object( $res );
 534                 if( $this->lastErrno() ) {
 535                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): '
 536                                 . htmlspecialchars( $this->lastError() ) );
 537                 }
 538                 return $row;
 539         }
 540
 541         /**
 542          * Fetch the next row from the given result object, in associative array
 543          * form. Fields are retrieved with $row['fieldname'].
 544          *
 545          * @param $res SQL result object as returned from Database::query(), etc.
 546          * @return DB2 row object
 547          * @throws DBUnexpectedError Thrown if the database returns an error
 548          */
 549         public function fetchRow( $res ) {
 550                 if ( $res instanceof ResultWrapper ) {
 551                         $res = $res->result;
 552                 }
 553                 @$row = db2_fetch_array( $res );
 554                 if ( $this->lastErrno() ) {
 555                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): '
 556                                 . htmlspecialchars( $this->lastError() ) );
 557                 }
 558                 return $row;
 559         }
 560
 561         /**
 562          * Create tables, stored procedures, and so on
 563          */
 564         public function setup_database() {
 565                 try {
 566                         // TODO: switch to root login if available
 567
 568                         // Switch into the correct namespace
 569                         $this->applySchema();
 570                         $this->begin();
 571
 572                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 573                         if ( $res !== true ) {
 574                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 575                         } else {
 576                                 print ' done</li>';
 577                         }
 578                         $res = $this->sourceFile( "../maintenance/ibm_db2/foreignkeys.sql" );
 579                         if ( $res !== true ) {
 580                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 581                         } else {
 582                                 print '<li>Foreign keys done</li>';
 583                         }
 584
 585                         // TODO: populate interwiki links
 586
 587                         if ( $this->lastError() ) {
 588                                 $this->installPrint(
 589                                         'Errors encountered during table creation -- rolled back' );
 590                                 $this->installPrint( 'Please install again' );
 591                                 $this->rollback();
 592                         } else {
 593                                 $this->commit();
 594                         }
 595                 } catch ( MWException $mwe ) {
 596                         print "<br><pre>$mwe</pre><br>";
 597                 }
 598         }
 599
 600         /**
 601          * Escapes strings
 602          * Doesn't escape numbers
 603          *
 604          * @param $s String: string to escape
 605          * @return escaped string
 606          */
 607         public function addQuotes( $s ) {
 608                 //$this->installPrint( "DB2::addQuotes( $s )\n" );
 609                 if ( is_null( $s ) ) {
 610                         return 'NULL';
 611                 } elseif ( $s instanceof Blob ) {
 612                         return "'" . $s->fetch( $s ) . "'";
 613                 } elseif ( $s instanceof IBM_DB2Blob ) {
 614                         return "'" . $this->decodeBlob( $s ) . "'";
 615                 }
 616                 $s = $this->strencode( $s );
 617                 if ( is_numeric( $s ) ) {
 618                         return $s;
 619                 } else {
 620                         return "'$s'";
 621                 }
 622         }
 623
 624         /**
 625          * Verifies that a DB2 column/field type is numeric
 626          *
 627          * @param $type String: DB2 column type
 628          * @return Boolean: true if numeric
 629          */
 630         public function is_numeric_type( $type ) {
 631                 switch ( strtoupper( $type ) ) {
 632                         case 'SMALLINT':
 633                         case 'INTEGER':
 634                         case 'INT':
 635                         case 'BIGINT':
 636                         case 'DECIMAL':
 637                         case 'REAL':
 638                         case 'DOUBLE':
 639                         case 'DECFLOAT':
 640                                 return true;
 641                 }
 642                 return false;
 643         }
 644
 645         /**
 646          * Alias for addQuotes()
 647          * @param $s String: string to escape
 648          * @return escaped string
 649          */
 650         public function strencode( $s ) {
 651                 // Bloody useless function
 652                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 653                 //  But also necessary
 654                 $s = db2_escape_string( $s );
 655                 // Wide characters are evil -- some of them look like '
 656                 $s = utf8_encode( $s );
 657                 // Fix its stupidity
 658                 $from = array(  "\\\\", "\\'",  '\\n',  '\\t',  '\\"',  '\\r' );
 659                 $to = array(            "\\",           "''",           "\n",           "\t",           '"',            "\r" );
 660                 $s = str_replace( $from, $to, $s ); // DB2 expects '', not \' escaping
 661                 return $s;
 662         }
 663
 664         /**
 665          * Switch into the database schema
 666          */
 667         protected function applySchema() {
 668                 if ( !( $this->mSchemaSet ) ) {
 669                         $this->mSchemaSet = true;
 670                         $this->begin();
 671                         $this->doQuery( "SET SCHEMA = $this->mSchema" );
 672                         $this->commit();
 673                 }
 674         }
 675
 676         /**
 677          * Start a transaction (mandatory)
 678          */
 679         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 680                 // BEGIN is implicit for DB2
 681                 // However, it requires that AutoCommit be off.
 682
 683                 // Some MediaWiki code is still transaction-less (?).
 684                 // The strategy is to keep AutoCommit on for that code
 685                 //  but switch it off whenever a transaction is begun.
 686                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_OFF );
 687
 688                 $this->mTrxLevel = 1;
 689         }
 690
 691         /**
 692          * End a transaction
 693          * Must have a preceding begin()
 694          */
 695         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 696                 db2_commit( $this->mConn );
 697
 698                 // Some MediaWiki code is still transaction-less (?).
 699                 // The strategy is to keep AutoCommit on for that code
 700                 //  but switch it off whenever a transaction is begun.
 701                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 702
 703                 $this->mTrxLevel = 0;
 704         }
 705
 706         /**
 707          * Cancel a transaction
 708          */
 709         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 710                 db2_rollback( $this->mConn );
 711                 // turn auto-commit back on
 712                 // not sure if this is appropriate
 713                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 714                 $this->mTrxLevel = 0;
 715         }
 716
 717         /**
 718          * Makes an encoded list of strings from an array
 719          * $mode:
 720          *   LIST_COMMA         - comma separated, no field names
 721          *   LIST_AND           - ANDed WHERE clause (without the WHERE)
 722          *   LIST_OR            - ORed WHERE clause (without the WHERE)
 723          *   LIST_SET           - comma separated with field names, like a SET clause
 724          *   LIST_NAMES         - comma separated field names
 725          *   LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 726          */
 727         function makeList( $a, $mode = LIST_COMMA ) {
 728                 if ( !is_array( $a ) ) {
 729                         throw new DBUnexpectedError( $this,
 730                                 'DatabaseIbm_db2::makeList called with incorrect parameters' );
 731                 }
 732
 733                 // if this is for a prepared UPDATE statement
 734                 // (this should be promoted to the parent class
 735                 //  once other databases use prepared statements)
 736                 if ( $mode == LIST_SET_PREPARED ) {
 737                         $first = true;
 738                         $list = '';
 739                         foreach ( $a as $field => $value ) {
 740                                 if ( !$first ) {
 741                                         $list .= ", $field = ?";
 742                                 } else {
 743                                         $list .= "$field = ?";
 744                                         $first = false;
 745                                 }
 746                         }
 747                         $list .= '';
 748
 749                         return $list;
 750                 }
 751
 752                 // otherwise, call the usual function
 753                 return parent::makeList( $a, $mode );
 754         }
 755
 756         /**
 757          * Construct a LIMIT query with optional offset
 758          * This is used for query pages
 759          *
 760          * @param $sql string SQL query we will append the limit too
 761          * @param $limit integer the SQL limit
 762          * @param $offset integer the SQL offset (default false)
 763          */
 764         public function limitResult( $sql, $limit, $offset=false ) {
 765                 if( !is_numeric( $limit ) ) {
 766                         throw new DBUnexpectedError( $this,
 767                                 "Invalid non-numeric limit passed to limitResult()\n" );
 768                 }
 769                 if( $offset ) {
 770                         if ( stripos( $sql, 'where' ) === false ) {
 771                                 return "$sql AND ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 772                         } else {
 773                                 return "$sql WHERE ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 774                         }
 775                 }
 776                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 777         }
 778
 779         /**
 780          * Handle reserved keyword replacement in table names
 781          *
 782          * @param $name Object
 783          * @return String
 784          */
 785         public function tableName( $name ) {
 786                 // we want maximum compatibility with MySQL schema
 787                 return $name;
 788         }
 789
 790         /**
 791          * Generates a timestamp in an insertable format
 792          *
 793          * @param $ts timestamp
 794          * @return String: timestamp value
 795          */
 796         public function timestamp( $ts = 0 ) {
 797                 // TS_MW cannot be easily distinguished from an integer
 798                 return wfTimestamp( TS_DB2, $ts );
 799         }
 800
 801         /**
 802          * Return the next in a sequence, save the value for retrieval via insertId()
 803          * @param $seqName String: name of a defined sequence in the database
 804          * @return next value in that sequence
 805          */
 806         public function nextSequenceValue( $seqName ) {
 807                 // Not using sequences in the primary schema to allow for easier migration
 808                 //  from MySQL
 809                 // Emulating MySQL behaviour of using NULL to signal that sequences
 810                 // aren't used
 811                 /*
 812                 $safeseq = preg_replace( "/'/", "''", $seqName );
 813                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 814                 $row = $this->fetchRow( $res );
 815                 $this->mInsertId = $row[0];
 816                 return $this->mInsertId;
 817                 */
 818                 return null;
 819         }
 820
 821         /**
 822          * This must be called after nextSequenceVal
 823          * @return Last sequence value used as a primary key
 824          */
 825         public function insertId() {
 826                 return $this->mInsertId;
 827         }
 828
 829         /**
 830          * Updates the mInsertId property with the value of the last insert
 831          *  into a generated column
 832          *
 833          * @param $table      String: sanitized table name
 834          * @param $primaryKey Mixed: string name of the primary key
 835          * @param $stmt       Resource: prepared statement resource
 836          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
 837          */
 838         private function calcInsertId( $table, $primaryKey, $stmt ) {
 839                 if ( $primaryKey ) {
 840                         $this->mInsertId = db2_last_insert_id( $this->mConn );
 841                 }
 842         }
 843
 844         /**
 845          * INSERT wrapper, inserts an array into a table
 846          *
 847          * $args may be a single associative array, or an array of arrays
 848          *  with numeric keys, for multi-row insert
 849          *
 850          * @param $table   String: Name of the table to insert to.
 851          * @param $args    Array: Items to insert into the table.
 852          * @param $fname   String: Name of the function, for profiling
 853          * @param $options String or Array. Valid options: IGNORE
 854          *
 855          * @return bool Success of insert operation. IGNORE always returns true.
 856          */
 857         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert',
 858                 $options = array() )
 859         {
 860                 if ( !count( $args ) ) {
 861                         return true;
 862                 }
 863                 // get database-specific table name (not used)
 864                 $table = $this->tableName( $table );
 865                 // format options as an array
 866                 $options = IBM_DB2Helper::makeArray( $options );
 867                 // format args as an array of arrays
 868                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
 869                         $args = array( $args );
 870                 }
 871
 872                 // prevent insertion of NULL into primary key columns
 873                 list( $args, $primaryKeys ) = $this->removeNullPrimaryKeys( $table, $args );
 874                 // if there's only one primary key
 875                 // we'll be able to read its value after insertion
 876                 $primaryKey = false;
 877                 if ( count( $primaryKeys ) == 1 ) {
 878                         $primaryKey = $primaryKeys[0];
 879                 }
 880
 881                 // get column names
 882                 $keys = array_keys( $args[0] );
 883                 $key_count = count( $keys );
 884
 885                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 886                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
 887
 888                 // assume success
 889                 $res = true;
 890                 // If we are not in a transaction, we need to be for savepoint trickery
 891                 if ( !$this->mTrxLevel ) {
 892                         $this->begin();
 893                 }
 894
 895                 $sql = "INSERT INTO $table ( " . implode( ',', $keys ) . ' ) VALUES ';
 896                 if ( $key_count == 1 ) {
 897                         $sql .= '( ? )';
 898                 } else {
 899                         $sql .= '( ?' . str_repeat( ',?', $key_count-1 ) . ' )';
 900                 }
 901                 //$this->installPrint( "Preparing the following SQL:" );
 902                 //$this->installPrint( "$sql" );
 903                 //$this->installPrint( print_r( $args, true ));
 904                 $stmt = $this->prepare( $sql );
 905
 906                 // start a transaction/enter transaction mode
 907                 $this->begin();
 908
 909                 if ( !$ignore ) {
 910                         //$first = true;
 911                         foreach ( $args as $row ) {
 912                                 //$this->installPrint( "Inserting " . print_r( $row, true ));
 913                                 // insert each row into the database
 914                                 $res = $res & $this->execute( $stmt, $row );
 915                                 if ( !$res ) {
 916                                         $this->installPrint( 'Last error:' );
 917                                         $this->installPrint( $this->lastError() );
 918                                 }
 919                                 // get the last inserted value into a generated column
 920                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 921                         }
 922                 } else {
 923                         $olde = error_reporting( 0 );
 924                         // For future use, we may want to track the number of actual inserts
 925                         // Right now, insert (all writes) simply return true/false
 926                         $numrowsinserted = 0;
 927
 928                         // always return true
 929                         $res = true;
 930
 931                         foreach ( $args as $row ) {
 932                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
 933                                 db2_exec( $this->mConn, $overhead, $this->mStmtOptions );
 934
 935                                 $this->execute( $stmt, $row );
 936
 937                                 if ( !$res2 ) {
 938                                         $this->installPrint( 'Last error:' );
 939                                         $this->installPrint( $this->lastError() );
 940                                 }
 941                                 // get the last inserted value into a generated column
 942                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 943
 944                                 $errNum = $this->lastErrno();
 945                                 if ( $errNum ) {
 946                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore",
 947                                                 $this->mStmtOptions );
 948                                 } else {
 949                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore",
 950                                                 $this->mStmtOptions );
 951                                         $numrowsinserted++;
 952                                 }
 953                         }
 954
 955                         $olde = error_reporting( $olde );
 956                         // Set the affected row count for the whole operation
 957                         $this->mAffectedRows = $numrowsinserted;
 958                 }
 959                 // commit either way
 960                 $this->commit();
 961                 $this->freePrepared( $stmt );
 962
 963                 return $res;
 964         }
 965
 966         /**
 967          * Given a table name and a hash of columns with values
 968          * Removes primary key columns from the hash where the value is NULL
 969          *
 970          * @param $table String: name of the table
 971          * @param $args Array of hashes of column names with values
 972          * @return Array: tuple( filtered array of columns, array of primary keys )
 973          */
 974         private function removeNullPrimaryKeys( $table, $args ) {
 975                 $schema = $this->mSchema;
 976                 // find out the primary keys
 977                 $keyres = db2_primary_keys( $this->mConn, null, strtoupper( $schema ),
 978                         strtoupper( $table )
 979                 );
 980                 $keys = array();
 981                 for (
 982                         $row = $this->fetchObject( $keyres );
 983                         $row != null;
 984                         $row = $this->fetchObject( $keyres )
 985                 )
 986                 {
 987                         $keys[] = strtolower( $row->column_name );
 988                 }
 989                 // remove primary keys
 990                 foreach ( $args as $ai => $row ) {
 991                         foreach ( $keys as $key ) {
 992                                 if ( $row[$key] == null ) {
 993                                         unset( $row[$key] );
 994                                 }
 995                         }
 996                         $args[$ai] = $row;
 997                 }
 998                 // return modified hash
 999                 return array( $args, $keys );
1000         }
1001
1002         /**
1003          * UPDATE wrapper, takes a condition array and a SET array
1004          *
1005          * @param $table  String: The table to UPDATE
1006          * @param $values An array of values to SET
1007          * @param $conds  An array of conditions ( WHERE ). Use '*' to update all rows.
1008          * @param $fname  String: The Class::Function calling this function
1009          *                ( for the log )
1010          * @param $options An array of UPDATE options, can be one or
1011          *                 more of IGNORE, LOW_PRIORITY
1012          * @return Boolean
1013          */
1014         public function update( $table, $values, $conds, $fname = 'DatabaseIbm_db2::update',
1015                 $options = array() )
1016         {
1017                 $table = $this->tableName( $table );
1018                 $opts = $this->makeUpdateOptions( $options );
1019                 $sql = "UPDATE $opts $table SET "
1020                         . $this->makeList( $values, LIST_SET_PREPARED );
1021                 if ( $conds != '*' ) {
1022                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1023                 }
1024                 $stmt = $this->prepare( $sql );
1025                 $this->installPrint( 'UPDATE: ' . print_r( $values, true ) );
1026                 // assuming for now that an array with string keys will work
1027                 // if not, convert to simple array first
1028                 $result = $this->execute( $stmt, $values );
1029                 $this->freePrepared( $stmt );
1030
1031                 return $result;
1032         }
1033
1034         /**
1035          * DELETE query wrapper
1036          *
1037          * Use $conds == "*" to delete all rows
1038          */
1039         public function delete( $table, $conds, $fname = 'DatabaseIbm_db2::delete' ) {
1040                 if ( !$conds ) {
1041                         throw new DBUnexpectedError( $this,
1042                                 'DatabaseIbm_db2::delete() called with no conditions' );
1043                 }
1044                 $table = $this->tableName( $table );
1045                 $sql = "DELETE FROM $table";
1046                 if ( $conds != '*' ) {
1047                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1048                 }
1049                 $result = $this->query( $sql, $fname );
1050
1051                 return $result;
1052         }
1053
1054         /**
1055          * Returns the number of rows affected by the last query or 0
1056          * @return Integer: the number of rows affected by the last query
1057          */
1058         public function affectedRows() {
1059                 if ( !is_null( $this->mAffectedRows ) ) {
1060                         // Forced result for simulated queries
1061                         return $this->mAffectedRows;
1062                 }
1063                 if( empty( $this->mLastResult ) ) {
1064                         return 0;
1065                 }
1066                 return db2_num_rows( $this->mLastResult );
1067         }
1068
1069         /**
1070          * Simulates REPLACE with a DELETE followed by INSERT
1071          * @param $table Object
1072          * @param $uniqueIndexes Array consisting of indexes and arrays of indexes
1073          * @param $rows Array: rows to insert
1074          * @param $fname String: name of the function for profiling
1075          * @return nothing
1076          */
1077         function replace( $table, $uniqueIndexes, $rows,
1078                 $fname = 'DatabaseIbm_db2::replace' )
1079         {
1080                 $table = $this->tableName( $table );
1081
1082                 if ( count( $rows )==0 ) {
1083                         return;
1084                 }
1085
1086                 # Single row case
1087                 if ( !is_array( reset( $rows ) ) ) {
1088                         $rows = array( $rows );
1089                 }
1090
1091                 foreach( $rows as $row ) {
1092                         # Delete rows which collide
1093                         if ( $uniqueIndexes ) {
1094                                 $sql = "DELETE FROM $table WHERE ";
1095                                 $first = true;
1096                                 foreach ( $uniqueIndexes as $index ) {
1097                                         if ( $first ) {
1098                                                 $first = false;
1099                                                 $sql .= '( ';
1100                                         } else {
1101                                                 $sql .= ' ) OR ( ';
1102                                         }
1103                                         if ( is_array( $index ) ) {
1104                                                 $first2 = true;
1105                                                 foreach ( $index as $col ) {
1106                                                         if ( $first2 ) {
1107                                                                 $first2 = false;
1108                                                         } else {
1109                                                                 $sql .= ' AND ';
1110                                                         }
1111                                                         $sql .= $col . '=' . $this->addQuotes( $row[$col] );
1112                                                 }
1113                                         } else {
1114                                                 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
1115                                         }
1116                                 }
1117                                 $sql .= ' )';
1118                                 $this->query( $sql, $fname );
1119                         }
1120
1121                         # Now insert the row
1122                         $sql = "INSERT INTO $table ( "
1123                                 . $this->makeList( array_keys( $row ), LIST_NAMES )
1124                                 .' ) VALUES ( ' . $this->makeList( $row, LIST_COMMA ) . ' )';
1125                         $this->query( $sql, $fname );
1126                 }
1127         }
1128
1129         /**
1130          * Returns the number of rows in the result set
1131          * Has to be called right after the corresponding select query
1132          * @param $res Object result set
1133          * @return Integer: number of rows
1134          */
1135         public function numRows( $res ) {
1136                 if ( $res instanceof ResultWrapper ) {
1137                         $res = $res->result;
1138                 }
1139                 if ( $this->mNumRows ) {
1140                         return $this->mNumRows;
1141                 } else {
1142                         return 0;
1143                 }
1144         }
1145
1146         /**
1147          * Moves the row pointer of the result set
1148          * @param $res Object: result set
1149          * @param $row Integer: row number
1150          * @return success or failure
1151          */
1152         public function dataSeek( $res, $row ) {
1153                 if ( $res instanceof ResultWrapper ) {
1154                         $res = $res->result;
1155                 }
1156                 return db2_fetch_row( $res, $row );
1157         }
1158
1159         ###
1160         # Fix notices in Block.php
1161         ###
1162
1163         /**
1164          * Frees memory associated with a statement resource
1165          * @param $res Object: statement resource to free
1166          * @return Boolean success or failure
1167          */
1168         public function freeResult( $res ) {
1169                 if ( $res instanceof ResultWrapper ) {
1170                         $res = $res->result;
1171                 }
1172                 if ( !@db2_free_result( $res ) ) {
1173                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
1174                 }
1175         }
1176
1177         /**
1178          * Returns the number of columns in a resource
1179          * @param $res Object: statement resource
1180          * @return Number of fields/columns in resource
1181          */
1182         public function numFields( $res ) {
1183                 if ( $res instanceof ResultWrapper ) {
1184                         $res = $res->result;
1185                 }
1186                 return db2_num_fields( $res );
1187         }
1188
1189         /**
1190          * Returns the nth column name
1191          * @param $res Object: statement resource
1192          * @param $n Integer: Index of field or column
1193          * @return String name of nth column
1194          */
1195         public function fieldName( $res, $n ) {
1196                 if ( $res instanceof ResultWrapper ) {
1197                         $res = $res->result;
1198                 }
1199                 return db2_field_name( $res, $n );
1200         }
1201
1202         /**
1203          * SELECT wrapper
1204          *
1205          * @param $table   Array or string, table name(s) (prefix auto-added)
1206          * @param $vars    Array or string, field name(s) to be retrieved
1207          * @param $conds   Array or string, condition(s) for WHERE
1208          * @param $fname   String: calling function name (use __METHOD__)
1209          *                 for logs/profiling
1210          * @param $options Associative array of options
1211          *                 (e.g. array('GROUP BY' => 'page_title')),
1212          *                 see Database::makeSelectOptions code for list of
1213          *                 supported stuff
1214          * @param $join_conds Associative array of table join conditions (optional)
1215          *                    (e.g. array( 'page' => array('LEFT JOIN',
1216          *                    'page_latest=rev_id') )
1217          * @return Mixed: database result resource for fetch functions or false
1218          *                 on failure
1219          */
1220         public function select( $table, $vars, $conds = '', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1221         {
1222                 $res = parent::select( $table, $vars, $conds, $fname, $options,
1223                         $join_conds );
1224
1225                 // We must adjust for offset
1226                 if ( isset( $options['LIMIT'] ) && isset ( $options['OFFSET'] ) ) {
1227                         $limit = $options['LIMIT'];
1228                         $offset = $options['OFFSET'];
1229                 }
1230
1231                 // DB2 does not have a proper num_rows() function yet, so we must emulate
1232                 // DB2 9.5.4 and the corresponding ibm_db2 driver will introduce
1233                 //  a working one
1234                 // TODO: Yay!
1235
1236                 // we want the count
1237                 $vars2 = array( 'count( * ) as num_rows' );
1238                 // respecting just the limit option
1239                 $options2 = array();
1240                 if ( isset( $options['LIMIT'] ) ) {
1241                         $options2['LIMIT'] = $options['LIMIT'];
1242                 }
1243                 // but don't try to emulate for GROUP BY
1244                 if ( isset( $options['GROUP BY'] ) ) {
1245                         return $res;
1246                 }
1247
1248                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2,
1249                         $join_conds );
1250                 $obj = $this->fetchObject( $res2 );
1251                 $this->mNumRows = $obj->num_rows;
1252
1253                 return $res;
1254         }
1255
1256         /**
1257          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1258          * Has limited support for per-column options (colnum => 'DISTINCT')
1259          *
1260          * @private
1261          *
1262          * @param $options Associative array of options to be turned into
1263          *              an SQL query, valid keys are listed in the function.
1264          * @return Array
1265          */
1266         function makeSelectOptions( $options ) {
1267                 $preLimitTail = $postLimitTail = '';
1268                 $startOpts = '';
1269
1270                 $noKeyOptions = array();
1271                 foreach ( $options as $key => $option ) {
1272                         if ( is_numeric( $key ) ) {
1273                                 $noKeyOptions[$option] = true;
1274                         }
1275                 }
1276
1277                 if ( isset( $options['GROUP BY'] ) ) {
1278                         $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1279                 }
1280                 if ( isset( $options['HAVING'] ) ) {
1281                         $preLimitTail .= " HAVING {$options['HAVING']}";
1282                 }
1283                 if ( isset( $options['ORDER BY'] ) ) {
1284                         $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1285                 }
1286
1287                 if ( isset( $noKeyOptions['DISTINCT'] )
1288                         || isset( $noKeyOptions['DISTINCTROW'] ) )
1289                 {
1290                         $startOpts .= 'DISTINCT';
1291                 }
1292
1293                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1294         }
1295
1296         /**
1297          * Returns link to IBM DB2 free download
1298          * @return String: wikitext of a link to the server software's web site
1299          */
1300         public static function getSoftwareLink() {
1301                 return '[http://www.ibm.com/db2/express/ IBM DB2]';
1302         }
1303
1304         /**
1305          * Get search engine class. All subclasses of this
1306          * need to implement this if they wish to use searching.
1307          *
1308          * @return String
1309          */
1310         public function getSearchEngine() {
1311                 return 'SearchIBM_DB2';
1312         }
1313
1314         /**
1315          * Did the last database access fail because of deadlock?
1316          * @return Boolean
1317          */
1318         public function wasDeadlock() {
1319                 // get SQLSTATE
1320                 $err = $this->lastErrno();
1321                 switch( $err ) {
1322                         // This is literal port of the MySQL logic and may be wrong for DB2
1323                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1324                         case '57011':   // sql0904n, Resource unavailable, no rollback
1325                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1326                         $this->installPrint( "In a deadlock because of SQLSTATE $err" );
1327                         return true;
1328                 }
1329                 return false;
1330         }
1331
1332         /**
1333          * Ping the server and try to reconnect if it there is no connection
1334          * The connection may be closed and reopened while this happens
1335          * @return Boolean: whether the connection exists
1336          */
1337         public function ping() {
1338                 // db2_ping() doesn't exist
1339                 // Emulate
1340                 $this->close();
1341                 $this->mConn = $this->openUncataloged( $this->mDBName, $this->mUser,
1342                         $this->mPassword, $this->mServer, $this->mPort );
1343
1344                 return false;
1345         }
1346         ######################################
1347         # Unimplemented and not applicable
1348         ######################################
1349         /**
1350          * Not implemented
1351          * @return string ''
1352          */
1353         public function getStatus( $which = '%' ) {
1354                 $this->installPrint( 'Not implemented for DB2: getStatus()' );
1355                 return '';
1356         }
1357         /**
1358          * Not implemented
1359          * @return string $sql
1360          */
1361         public function limitResultForUpdate( $sql, $num ) {
1362                 $this->installPrint( 'Not implemented for DB2: limitResultForUpdate()' );
1363                 return $sql;
1364         }
1365
1366         /**
1367          * Only useful with fake prepare like in base Database class
1368          * @return      string
1369          */
1370         public function fillPreparedArg( $matches ) {
1371                 $this->installPrint( 'Not useful for DB2: fillPreparedArg()' );
1372                 return '';
1373         }
1374
1375         ######################################
1376         # Reflection
1377         ######################################
1378
1379         /**
1380          * Returns information about an index
1381          * If errors are explicitly ignored, returns NULL on failure
1382          * @param $table String: table name
1383          * @param $index String: index name
1384          * @param $fname String: function name for logging and profiling
1385          * @return Object query row in object form
1386          */
1387         public function indexInfo( $table, $index,
1388                 $fname = 'DatabaseIbm_db2::indexExists' )
1389         {
1390                 $table = $this->tableName( $table );
1391                 $sql = <<<SQL
1392 SELECT name as indexname
1393 FROM sysibm.sysindexes si
1394 WHERE si.name='$index' AND si.tbname='$table'
1395 AND sc.tbcreator='$this->mSchema'
1396 SQL;
1397                 $res = $this->query( $sql, $fname );
1398                 if ( !$res ) {
1399                         return null;
1400                 }
1401                 $row = $this->fetchObject( $res );
1402                 if ( $row != null ) {
1403                         return $row;
1404                 } else {
1405                         return false;
1406                 }
1407         }
1408
1409         /**
1410          * Returns an information object on a table column
1411          * @param $table String: table name
1412          * @param $field String: column name
1413          * @return IBM_DB2Field
1414          */
1415         public function fieldInfo( $table, $field ) {
1416                 return IBM_DB2Field::fromText( $this, $table, $field );
1417         }
1418
1419         /**
1420          * db2_field_type() wrapper
1421          * @param $res Object: result of executed statement
1422          * @param $index Mixed: number or name of the column
1423          * @return String column type
1424          */
1425         public function fieldType( $res, $index ) {
1426                 if ( $res instanceof ResultWrapper ) {
1427                         $res = $res->result;
1428                 }
1429                 return db2_field_type( $res, $index );
1430         }
1431
1432         /**
1433          * Verifies that an index was created as unique
1434          * @param $table String: table name
1435          * @param $index String: index name
1436          * @param $fname function name for profiling
1437          * @return Bool
1438          */
1439         public function indexUnique ( $table, $index,
1440                 $fname = 'DatabaseIbm_db2::indexUnique' )
1441         {
1442                 $table = $this->tableName( $table );
1443                 $sql = <<<SQL
1444 SELECT si.name as indexname
1445 FROM sysibm.sysindexes si
1446 WHERE si.name='$index' AND si.tbname='$table'
1447 AND sc.tbcreator='$this->mSchema'
1448 AND si.uniquerule IN ( 'U', 'P' )
1449 SQL;
1450                 $res = $this->query( $sql, $fname );
1451                 if ( !$res ) {
1452                         return null;
1453                 }
1454                 if ( $this->fetchObject( $res ) ) {
1455                         return true;
1456                 }
1457                 return false;
1458
1459         }
1460
1461         /**
1462          * Returns the size of a text field, or -1 for "unlimited"
1463          * @param $table String: table name
1464          * @param $field String: column name
1465          * @return Integer: length or -1 for unlimited
1466          */
1467         public function textFieldSize( $table, $field ) {
1468                 $table = $this->tableName( $table );
1469                 $sql = <<<SQL
1470 SELECT length as size
1471 FROM sysibm.syscolumns sc
1472 WHERE sc.name='$field' AND sc.tbname='$table'
1473 AND sc.tbcreator='$this->mSchema'
1474 SQL;
1475                 $res = $this->query( $sql );
1476                 $row = $this->fetchObject( $res );
1477                 $size = $row->size;
1478                 return $size;
1479         }
1480
1481         /**
1482          * DELETE where the condition is a join
1483          * @param $delTable String: deleting from this table
1484          * @param $joinTable String: using data from this table
1485          * @param $delVar String: variable in deleteable table
1486          * @param $joinVar String: variable in data table
1487          * @param $conds Array: conditionals for join table
1488          * @param $fname String: function name for profiling
1489          */
1490         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar,
1491                 $conds, $fname = "DatabaseIbm_db2::deleteJoin" )
1492         {
1493                 if ( !$conds ) {
1494                         throw new DBUnexpectedError( $this,
1495                                 'DatabaseIbm_db2::deleteJoin() called with empty $conds' );
1496                 }
1497
1498                 $delTable = $this->tableName( $delTable );
1499                 $joinTable = $this->tableName( $joinTable );
1500                 $sql = <<<SQL
1501 DELETE FROM $delTable
1502 WHERE $delVar IN (
1503   SELECT $joinVar FROM $joinTable
1504
1505 SQL;
1506                 if ( $conds != '*' ) {
1507                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1508                 }
1509                 $sql .= ' )';
1510
1511                 $this->query( $sql, $fname );
1512         }
1513
1514         /**
1515          * Description is left as an exercise for the reader
1516          * @param $b Mixed: data to be encoded
1517          * @return IBM_DB2Blob
1518          */
1519         public function encodeBlob( $b ) {
1520                 return new IBM_DB2Blob( $b );
1521         }
1522
1523         /**
1524          * Description is left as an exercise for the reader
1525          * @param $b IBM_DB2Blob: data to be decoded
1526          * @return mixed
1527          */
1528         public function decodeBlob( $b ) {
1529                 return "$b";
1530         }
1531
1532         /**
1533          * Convert into a list of string being concatenated
1534          * @param $stringList Array: strings that need to be joined together
1535          *                    by the SQL engine
1536          * @return String: joined by the concatenation operator
1537          */
1538         public function buildConcat( $stringList ) {
1539                 // || is equivalent to CONCAT
1540                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1541                 return implode( ' || ', $stringList );
1542         }
1543
1544         /**
1545          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1546          * @param $column String: name of timestamp column
1547          * @return String: SQL code
1548          */
1549         public function extractUnixEpoch( $column ) {
1550                 // TODO
1551                 // see SpecialAncientpages
1552         }
1553
1554         ######################################
1555         # Prepared statements
1556         ######################################
1557
1558         /**
1559          * Intended to be compatible with the PEAR::DB wrapper functions.
1560          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1561          *
1562          * ? = scalar value, quoted as necessary
1563          * ! = raw SQL bit (a function for instance)
1564          * & = filename; reads the file and inserts as a blob
1565          *     (we don't use this though...)
1566          * @param $sql String: SQL statement with appropriate markers
1567          * @param $func String: Name of the function, for profiling
1568          * @return resource a prepared DB2 SQL statement
1569          */
1570         public function prepare( $sql, $func = 'DB2::prepare' ) {
1571                 $stmt = db2_prepare( $this->mConn, $sql, $this->mStmtOptions );
1572                 return $stmt;
1573         }
1574
1575         /**
1576          * Frees resources associated with a prepared statement
1577          * @return Boolean success or failure
1578          */
1579         public function freePrepared( $prepared ) {
1580                 return db2_free_stmt( $prepared );
1581         }
1582
1583         /**
1584          * Execute a prepared query with the various arguments
1585          * @param $prepared String: the prepared sql
1586          * @param $args Mixed: either an array here, or put scalars as varargs
1587          * @return Resource: results object
1588          */
1589         public function execute( $prepared, $args = null ) {
1590                 if( !is_array( $args ) ) {
1591                         # Pull the var args
1592                         $args = func_get_args();
1593                         array_shift( $args );
1594                 }
1595                 $res = db2_execute( $prepared, $args );
1596                 if ( !$res ) {
1597                         $this->installPrint( db2_stmt_errormsg() );
1598                 }
1599                 return $res;
1600         }
1601
1602         /**
1603          * Prepare & execute an SQL statement, quoting and inserting arguments
1604          * in the appropriate places.
1605          * @param $query String
1606          * @param $args ...
1607          */
1608         public function safeQuery( $query, $args = null ) {
1609                 // copied verbatim from Database.php
1610                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1611                 if( !is_array( $args ) ) {
1612                         # Pull the var args
1613                         $args = func_get_args();
1614                         array_shift( $args );
1615                 }
1616                 $retval = $this->execute( $prepared, $args );
1617                 $this->freePrepared( $prepared );
1618                 return $retval;
1619         }
1620
1621         /**
1622          * For faking prepared SQL statements on DBs that don't support
1623          * it directly.
1624          * @param $preparedQuery String: a 'preparable' SQL statement
1625          * @param $args Array of arguments to fill it with
1626          * @return String: executable statement
1627          */
1628         public function fillPrepared( $preparedQuery, $args ) {
1629                 reset( $args );
1630                 $this->preparedArgs =& $args;
1631
1632                 foreach ( $args as $i => $arg ) {
1633                         db2_bind_param( $preparedQuery, $i+1, $args[$i] );
1634                 }
1635
1636                 return $preparedQuery;
1637         }
1638
1639         /**
1640          * Switches module between regular and install modes
1641          */
1642         public function setMode( $mode ) {
1643                 $old = $this->mMode;
1644                 $this->mMode = $mode;
1645                 return $old;
1646         }
1647
1648         /**
1649          * Bitwise negation of a column or value in SQL
1650          * Same as (~field) in C
1651          * @param $field String
1652          * @return String
1653          */
1654         function bitNot( $field ) {
1655                 // expecting bit-fields smaller than 4bytes
1656                 return "BITNOT( $field )";
1657         }
1658
1659         /**
1660          * Bitwise AND of two columns or values in SQL
1661          * Same as (fieldLeft & fieldRight) in C
1662          * @param $fieldLeft String
1663          * @param $fieldRight String
1664          * @return String
1665          */
1666         function bitAnd( $fieldLeft, $fieldRight ) {
1667                 return "BITAND( $fieldLeft, $fieldRight )";
1668         }
1669
1670         /**
1671          * Bitwise OR of two columns or values in SQL
1672          * Same as (fieldLeft | fieldRight) in C
1673          * @param $fieldLeft String
1674          * @param $fieldRight String
1675          * @return String
1676          */
1677         function bitOr( $fieldLeft, $fieldRight ) {
1678                 return "BITOR( $fieldLeft, $fieldRight )";
1679         }
1680 }
1681
1682 class IBM_DB2Helper {
1683         public static function makeArray( $maybeArray ) {
1684                 if ( !is_array( $maybeArray ) ) {
1685                         return array( $maybeArray );
1686                 }
1687
1688                 return $maybeArray;
1689         }
1690 }