includes/db/DatabaseIbm_db2.php

   1 <?php
   2 /**
   3  * This is the IBM DB2 database abstraction layer.
   4  * See maintenance/ibm_db2/README for development notes
   5  * and other specific information
   6  *
   7  * @file
   8  * @ingroup Database
   9  * @author leo.petr+mediawiki@gmail.com
  10  */
  11
  12 /**
  13  * This represents a column in a DB2 database
  14  * @ingroup Database
  15  */
  16 class IBM_DB2Field implements Field {
  17         private $name = '';
  18         private $tablename = '';
  19         private $type = '';
  20         private $nullable = false;
  21         private $max_length = 0;
  22
  23         /**
  24          * Builder method for the class
  25          * @param $db DatabaseIbm_db2: Database interface
  26          * @param $table String: table name
  27          * @param $field String: column name
  28          * @return IBM_DB2Field
  29          */
  30         static function fromText( $db, $table, $field ) {
  31                 global $wgDBmwschema;
  32
  33                 $q = <<<SQL
  34 SELECT
  35 lcase( coltype ) AS typname,
  36 nulls AS attnotnull, length AS attlen
  37 FROM sysibm.syscolumns
  38 WHERE tbcreator=%s AND tbname=%s AND name=%s;
  39 SQL;
  40                 $res = $db->query(
  41                         sprintf( $q,
  42                                 $db->addQuotes( $wgDBmwschema ),
  43                                 $db->addQuotes( $table ),
  44                                 $db->addQuotes( $field )
  45                         )
  46                 );
  47                 $row = $db->fetchObject( $res );
  48                 if ( !$row ) {
  49                         return null;
  50                 }
  51                 $n = new IBM_DB2Field;
  52                 $n->type = $row->typname;
  53                 $n->nullable = ( $row->attnotnull == 'N' );
  54                 $n->name = $field;
  55                 $n->tablename = $table;
  56                 $n->max_length = $row->attlen;
  57                 return $n;
  58         }
  59         /**
  60          * Get column name
  61          * @return string column name
  62          */
  63         function name() { return $this->name; }
  64         /**
  65          * Get table name
  66          * @return string table name
  67          */
  68         function tableName() { return $this->tablename; }
  69         /**
  70          * Get column type
  71          * @return string column type
  72          */
  73         function type() { return $this->type; }
  74         /**
  75          * Can column be null?
  76          * @return bool true or false
  77          */
  78         function isNullable() { return $this->nullable; }
  79         /**
  80          * How much can you fit in the column per row?
  81          * @return int length
  82          */
  83         function maxLength() { return $this->max_length; }
  84 }
  85
  86 /**
  87  * Wrapper around binary large objects
  88  * @ingroup Database
  89  */
  90 class IBM_DB2Blob {
  91         private $mData;
  92
  93         public function __construct( $data ) {
  94                 $this->mData = $data;
  95         }
  96
  97         public function getData() {
  98                 return $this->mData;
  99         }
 100
 101         public function __toString() {
 102                 return $this->mData;
 103         }
 104 }
 105
 106 /**
 107  * Primary database interface
 108  * @ingroup Database
 109  */
 110 class DatabaseIbm_db2 extends DatabaseBase {
 111         /*
 112          * Inherited members
 113         protected $mLastQuery = '';
 114         protected $mPHPError = false;
 115
 116         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 117         protected $mOpened = false;
 118
 119         protected $mTablePrefix;
 120         protected $mFlags;
 121         protected $mTrxLevel = 0;
 122         protected $mErrorCount = 0;
 123         protected $mLBInfo = array();
 124         protected $mFakeSlaveLag = null, $mFakeMaster = false;
 125          *
 126          */
 127
 128         /** Database server port */
 129         protected $mPort = null;
 130         /** Schema for tables, stored procedures, triggers */
 131         protected $mSchema = null;
 132         /** Whether the schema has been applied in this session */
 133         protected $mSchemaSet = false;
 134         /** Result of last query */
 135         protected $mLastResult = null;
 136         /** Number of rows affected by last INSERT/UPDATE/DELETE */
 137         protected $mAffectedRows = null;
 138         /** Number of rows returned by last SELECT */
 139         protected $mNumRows = null;
 140
 141         /** Connection config options - see constructor */
 142         public $mConnOptions = array();
 143         /** Statement config options -- see constructor */
 144         public $mStmtOptions = array();
 145
 146         /** Default schema */
 147         const USE_GLOBAL = 'get from global';
 148
 149         /** Option that applies to nothing */
 150         const NONE_OPTION = 0x00;
 151         /** Option that applies to connection objects */
 152         const CONN_OPTION = 0x01;
 153         /** Option that applies to statement objects */
 154         const STMT_OPTION = 0x02;
 155
 156         /** Regular operation mode -- minimal debug messages */
 157         const REGULAR_MODE = 'regular';
 158         /** Installation mode -- lots of debug messages */
 159         const INSTALL_MODE = 'install';
 160
 161         /** Controls the level of debug message output */
 162         protected $mMode = self::REGULAR_MODE;
 163
 164         /** Last sequence value used for a primary key */
 165         protected $mInsertId = null;
 166
 167         ######################################
 168         # Getters and Setters
 169         ######################################
 170
 171         /**
 172          * Returns true if this database supports (and uses) cascading deletes
 173          */
 174         function cascadingDeletes() {
 175                 return true;
 176         }
 177
 178         /**
 179          * Returns true if this database supports (and uses) triggers (e.g. on the
 180          *  page table)
 181          */
 182         function cleanupTriggers() {
 183                 return true;
 184         }
 185
 186         /**
 187          * Returns true if this database is strict about what can be put into an
 188          *  IP field.
 189          * Specifically, it uses a NULL value instead of an empty string.
 190          */
 191         function strictIPs() {
 192                 return true;
 193         }
 194
 195         /**
 196          * Returns true if this database uses timestamps rather than integers
 197         */
 198         function realTimestamps() {
 199                 return true;
 200         }
 201
 202         /**
 203          * Returns true if this database does an implicit sort when doing GROUP BY
 204          */
 205         function implicitGroupby() {
 206                 return false;
 207         }
 208
 209         /**
 210          * Returns true if this database does an implicit order by when the column
 211          *  has an index
 212          * For example: SELECT page_title FROM page LIMIT 1
 213          */
 214         function implicitOrderby() {
 215                 return false;
 216         }
 217
 218         /**
 219          * Returns true if this database can do a native search on IP columns
 220          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 221          */
 222         function searchableIPs() {
 223                 return true;
 224         }
 225
 226         /**
 227          * Returns true if this database can use functional indexes
 228          */
 229         function functionalIndexes() {
 230                 return true;
 231         }
 232
 233         /**
 234          * Returns a unique string representing the wiki on the server
 235          */
 236         function getWikiID() {
 237                 if( $this->mSchema ) {
 238                         return "{$this->mDBname}-{$this->mSchema}";
 239                 } else {
 240                         return $this->mDBname;
 241                 }
 242         }
 243
 244         function getType() {
 245                 return 'ibm_db2';
 246         }
 247
 248         /**
 249          *
 250          * @param $server String: hostname of database server
 251          * @param $user String: username
 252          * @param $password String: password
 253          * @param $dbName String: database name on the server
 254          * @param $flags Integer: database behaviour flags (optional, unused)
 255          * @param $schema String
 256          */
 257         public function __construct( $server = false, $user = false,
 258                                                         $password = false,
 259                                                         $dbName = false, $flags = 0,
 260                                                         $schema = self::USE_GLOBAL )
 261         {
 262                 global $wgDBmwschema;
 263
 264                 if ( $schema == self::USE_GLOBAL ) {
 265                         $this->mSchema = $wgDBmwschema;
 266                 } else {
 267                         $this->mSchema = $schema;
 268                 }
 269
 270                 // configure the connection and statement objects
 271                 /*
 272                 $this->setDB2Option( 'cursor', 'DB2_SCROLLABLE',
 273                         self::CONN_OPTION | self::STMT_OPTION );
 274                 */
 275                 $this->setDB2Option( 'db2_attr_case', 'DB2_CASE_LOWER',
 276                         self::CONN_OPTION | self::STMT_OPTION );
 277                 $this->setDB2Option( 'deferred_prepare', 'DB2_DEFERRED_PREPARE_ON',
 278                         self::STMT_OPTION );
 279                 $this->setDB2Option( 'rowcount', 'DB2_ROWCOUNT_PREFETCH_ON',
 280                         self::STMT_OPTION );
 281
 282                 parent::__construct( $server, $user, $password, $dbName, DBO_TRX | $flags );
 283         }
 284
 285         /**
 286          * Enables options only if the ibm_db2 extension version supports them
 287          * @param $name String: name of the option in the options array
 288          * @param $const String: name of the constant holding the right option value
 289          * @param $type Integer: whether this is a Connection or Statement otion
 290          */
 291         private function setDB2Option( $name, $const, $type ) {
 292                 if ( defined( $const ) ) {
 293                         if ( $type & self::CONN_OPTION ) {
 294                                 $this->mConnOptions[$name] = constant( $const );
 295                         }
 296                         if ( $type & self::STMT_OPTION ) {
 297                                 $this->mStmtOptions[$name] = constant( $const );
 298                         }
 299                 } else {
 300                         $this->installPrint(
 301                                 "$const is not defined. ibm_db2 version is likely too low." );
 302                 }
 303         }
 304
 305         /**
 306          * Outputs debug information in the appropriate place
 307          * @param $string String: the relevant debug message
 308          */
 309         private function installPrint( $string ) {
 310                 wfDebug( "$string\n" );
 311                 if ( $this->mMode == self::INSTALL_MODE ) {
 312                         print "<li><pre>$string</pre></li>";
 313                         flush();
 314                 }
 315         }
 316
 317         /**
 318          * Opens a database connection and returns it
 319          * Closes any existing connection
 320          *
 321          * @param $server String: hostname
 322          * @param $user String
 323          * @param $password String
 324          * @param $dbName String: database name
 325          * @return a fresh connection
 326          */
 327         public function open( $server, $user, $password, $dbName ) {
 328                 wfProfileIn( __METHOD__ );
 329
 330                 # Load IBM DB2 driver if missing
 331                 wfDl( 'ibm_db2' );
 332
 333                 # Test for IBM DB2 support, to avoid suppressed fatal error
 334                 if ( !function_exists( 'db2_connect' ) ) {
 335                         throw new DBConnectionError( $this, "DB2 functions missing, have you enabled the ibm_db2 extension for PHP?" );
 336                 }
 337
 338                 global $wgDBport;
 339
 340                 // Close existing connection
 341                 $this->close();
 342                 // Cache conn info
 343                 $this->mServer = $server;
 344                 $this->mPort = $port = $wgDBport;
 345                 $this->mUser = $user;
 346                 $this->mPassword = $password;
 347                 $this->mDBname = $dbName;
 348
 349                 $this->openUncataloged( $dbName, $user, $password, $server, $port );
 350
 351                 if ( !$this->mConn ) {
 352                         $this->installPrint( "DB connection error\n" );
 353                         $this->installPrint(
 354                                 "Server: $server, Database: $dbName, User: $user, Password: "
 355                                 . substr( $password, 0, 3 ) . "...\n" );
 356                         $this->installPrint( $this->lastError() . "\n" );
 357                         wfProfileOut( __METHOD__ );
 358                         wfDebug( "DB connection error\n" );
 359                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 360                         wfDebug( $this->lastError() . "\n" );
 361                         throw new DBConnectionError( $this, $this->lastError() );
 362                 }
 363
 364                 // Apply connection config
 365                 db2_set_option( $this->mConn, $this->mConnOptions, 1 );
 366                 // Some MediaWiki code is still transaction-less (?).
 367                 // The strategy is to keep AutoCommit on for that code
 368                 //  but switch it off whenever a transaction is begun.
 369                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 370
 371                 $this->mOpened = true;
 372                 $this->applySchema();
 373
 374                 wfProfileOut( __METHOD__ );
 375                 return $this->mConn;
 376         }
 377
 378         /**
 379          * Opens a cataloged database connection, sets mConn
 380          */
 381         protected function openCataloged( $dbName, $user, $password ) {
 382                 @$this->mConn = db2_pconnect( $dbName, $user, $password );
 383         }
 384
 385         /**
 386          * Opens an uncataloged database connection, sets mConn
 387          */
 388         protected function openUncataloged( $dbName, $user, $password, $server, $port )
 389         {
 390                 $dsn = "DRIVER={IBM DB2 ODBC DRIVER};DATABASE=$dbName;CHARSET=UTF-8;HOSTNAME=$server;PORT=$port;PROTOCOL=TCPIP;UID=$user;PWD=$password;";
 391                 @$this->mConn = db2_pconnect($dsn, "", "", array());
 392         }
 393
 394         /**
 395          * Closes a database connection, if it is open
 396          * Returns success, true if already closed
 397          */
 398         public function close() {
 399                 $this->mOpened = false;
 400                 if ( $this->mConn ) {
 401                         if ( $this->trxLevel() > 0 ) {
 402                                 $this->commit();
 403                         }
 404                         return db2_close( $this->mConn );
 405                 } else {
 406                         return true;
 407                 }
 408         }
 409
 410         /**
 411          * Retrieves the most current database error
 412          * Forces a database rollback
 413          */
 414         public function lastError() {
 415                 $connerr = db2_conn_errormsg();
 416                 if ( $connerr ) {
 417                         //$this->rollback();
 418                         return $connerr;
 419                 }
 420                 $stmterr = db2_stmt_errormsg();
 421                 if ( $stmterr ) {
 422                         //$this->rollback();
 423                         return $stmterr;
 424                 }
 425
 426                 return false;
 427         }
 428
 429         /**
 430          * Get the last error number
 431          * Return 0 if no error
 432          * @return integer
 433          */
 434         public function lastErrno() {
 435                 $connerr = db2_conn_error();
 436                 if ( $connerr ) {
 437                         return $connerr;
 438                 }
 439                 $stmterr = db2_stmt_error();
 440                 if ( $stmterr ) {
 441                         return $stmterr;
 442                 }
 443                 return 0;
 444         }
 445
 446         /**
 447          * Is a database connection open?
 448          * @return
 449          */
 450         public function isOpen() { return $this->mOpened; }
 451
 452         /**
 453          * The DBMS-dependent part of query()
 454          * @param  $sql String: SQL query.
 455          * @return object Result object for fetch functions or false on failure
 456          */
 457         protected function doQuery( $sql ) {
 458                 $this->applySchema();
 459
 460                 // Needed to handle any UTF-8 encoding issues in the raw sql
 461                 // Note that we fully support prepared statements for DB2
 462                 // prepare() and execute() should be used instead of doQuery() whenever possible
 463                 $sql = utf8_decode($sql);
 464
 465                 $ret = db2_exec( $this->mConn, $sql, $this->mStmtOptions );
 466                 if( $ret == false ) {
 467                         $error = db2_stmt_errormsg();
 468
 469                         $this->installPrint( "<pre>$sql</pre>" );
 470                         $this->installPrint( $error );
 471                         throw new DBUnexpectedError( $this, 'SQL error: '
 472                                 . htmlspecialchars( $error ) );
 473                 }
 474                 $this->mLastResult = $ret;
 475                 $this->mAffectedRows = null; // Not calculated until asked for
 476                 return $ret;
 477         }
 478
 479         /**
 480          * @return string Version information from the database
 481          */
 482         public function getServerVersion() {
 483                 $info = db2_server_info( $this->mConn );
 484                 return $info->DBMS_VER;
 485         }
 486
 487         /**
 488          * Queries whether a given table exists
 489          * @return boolean
 490          */
 491         public function tableExists( $table ) {
 492                 $schema = $this->mSchema;
 493
 494                 $sql = "SELECT COUNT( * ) FROM SYSIBM.SYSTABLES ST WHERE ST.NAME = '" .
 495                         strtoupper( $table ) .
 496                         "' AND ST.CREATOR = '" .
 497                         strtoupper( $schema ) . "'";
 498                 $res = $this->query( $sql );
 499                 if ( !$res ) {
 500                         return false;
 501                 }
 502
 503                 // If the table exists, there should be one of it
 504                 @$row = $this->fetchRow( $res );
 505                 $count = $row[0];
 506                 if ( $count == '1' || $count == 1 ) {
 507                         return true;
 508                 }
 509
 510                 return false;
 511         }
 512
 513         /**
 514          * Fetch the next row from the given result object, in object form.
 515          * Fields can be retrieved with $row->fieldname, with fields acting like
 516          * member variables.
 517          *
 518          * @param $res SQL result object as returned from Database::query(), etc.
 519          * @return DB2 row object
 520          * @throws DBUnexpectedError Thrown if the database returns an error
 521          */
 522         public function fetchObject( $res ) {
 523                 if ( $res instanceof ResultWrapper ) {
 524                         $res = $res->result;
 525                 }
 526                 @$row = db2_fetch_object( $res );
 527                 if( $this->lastErrno() ) {
 528                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): '
 529                                 . htmlspecialchars( $this->lastError() ) );
 530                 }
 531                 return $row;
 532         }
 533
 534         /**
 535          * Fetch the next row from the given result object, in associative array
 536          * form. Fields are retrieved with $row['fieldname'].
 537          *
 538          * @param $res SQL result object as returned from Database::query(), etc.
 539          * @return DB2 row object
 540          * @throws DBUnexpectedError Thrown if the database returns an error
 541          */
 542         public function fetchRow( $res ) {
 543                 if ( $res instanceof ResultWrapper ) {
 544                         $res = $res->result;
 545                 }
 546                 if ( db2_num_rows( $res ) > 0) {
 547                         @$row = db2_fetch_array( $res );
 548                         if ( $this->lastErrno() ) {
 549                                 throw new DBUnexpectedError( $this, 'Error in fetchRow(): '
 550                                         . htmlspecialchars( $this->lastError() ) );
 551                         }
 552                         return $row;
 553                 }
 554                 return false;
 555         }
 556
 557         /**
 558          * Create tables, stored procedures, and so on
 559          */
 560         public function setup_database() {
 561                 try {
 562                         // TODO: switch to root login if available
 563
 564                         // Switch into the correct namespace
 565                         $this->applySchema();
 566                         $this->begin();
 567
 568                         $res = $this->sourceFile( "../maintenance/ibm_db2/tables.sql" );
 569                         if ( $res !== true ) {
 570                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 571                         } else {
 572                                 print ' done</li>';
 573                         }
 574                         $res = $this->sourceFile( "../maintenance/ibm_db2/foreignkeys.sql" );
 575                         if ( $res !== true ) {
 576                                 print ' <b>FAILED</b>: ' . htmlspecialchars( $res ) . '</li>';
 577                         } else {
 578                                 print '<li>Foreign keys done</li>';
 579                         }
 580
 581                         // TODO: populate interwiki links
 582
 583                         if ( $this->lastError() ) {
 584                                 $this->installPrint(
 585                                         'Errors encountered during table creation -- rolled back' );
 586                                 $this->installPrint( 'Please install again' );
 587                                 $this->rollback();
 588                         } else {
 589                                 $this->commit();
 590                         }
 591                 } catch ( MWException $mwe ) {
 592                         print "<br><pre>$mwe</pre><br>";
 593                 }
 594         }
 595
 596         /**
 597          * Escapes strings
 598          * Doesn't escape numbers
 599          *
 600          * @param $s String: string to escape
 601          * @return escaped string
 602          */
 603         public function addQuotes( $s ) {
 604                 //$this->installPrint( "DB2::addQuotes( $s )\n" );
 605                 if ( is_null( $s ) ) {
 606                         return 'NULL';
 607                 } elseif ( $s instanceof Blob ) {
 608                         return "'" . $s->fetch( $s ) . "'";
 609                 } elseif ( $s instanceof IBM_DB2Blob ) {
 610                         return "'" . $this->decodeBlob( $s ) . "'";
 611                 }
 612                 $s = $this->strencode( $s );
 613                 if ( is_numeric( $s ) ) {
 614                         return $s;
 615                 } else {
 616                         return "'$s'";
 617                 }
 618         }
 619
 620         /**
 621          * Verifies that a DB2 column/field type is numeric
 622          *
 623          * @param $type String: DB2 column type
 624          * @return Boolean: true if numeric
 625          */
 626         public function is_numeric_type( $type ) {
 627                 switch ( strtoupper( $type ) ) {
 628                         case 'SMALLINT':
 629                         case 'INTEGER':
 630                         case 'INT':
 631                         case 'BIGINT':
 632                         case 'DECIMAL':
 633                         case 'REAL':
 634                         case 'DOUBLE':
 635                         case 'DECFLOAT':
 636                                 return true;
 637                 }
 638                 return false;
 639         }
 640
 641         /**
 642          * Alias for addQuotes()
 643          * @param $s String: string to escape
 644          * @return escaped string
 645          */
 646         public function strencode( $s ) {
 647                 // Bloody useless function
 648                 //  Prepends backslashes to \x00, \n, \r, \, ', " and \x1a.
 649                 //  But also necessary
 650                 $s = db2_escape_string( $s );
 651                 // Wide characters are evil -- some of them look like '
 652                 $s = utf8_encode( $s );
 653                 // Fix its stupidity
 654                 $from = array(  "\\\\", "\\'",  '\\n',  '\\t',  '\\"',  '\\r' );
 655                 $to = array(            "\\",           "''",           "\n",           "\t",           '"',            "\r" );
 656                 $s = str_replace( $from, $to, $s ); // DB2 expects '', not \' escaping
 657                 return $s;
 658         }
 659
 660         /**
 661          * Switch into the database schema
 662          */
 663         protected function applySchema() {
 664                 if ( !( $this->mSchemaSet ) ) {
 665                         $this->mSchemaSet = true;
 666                         $this->begin();
 667                         $this->doQuery( "SET SCHEMA = $this->mSchema" );
 668                         $this->commit();
 669                 }
 670         }
 671
 672         /**
 673          * Start a transaction (mandatory)
 674          */
 675         public function begin( $fname = 'DatabaseIbm_db2::begin' ) {
 676                 // BEGIN is implicit for DB2
 677                 // However, it requires that AutoCommit be off.
 678
 679                 // Some MediaWiki code is still transaction-less (?).
 680                 // The strategy is to keep AutoCommit on for that code
 681                 //  but switch it off whenever a transaction is begun.
 682                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_OFF );
 683
 684                 $this->mTrxLevel = 1;
 685         }
 686
 687         /**
 688          * End a transaction
 689          * Must have a preceding begin()
 690          */
 691         public function commit( $fname = 'DatabaseIbm_db2::commit' ) {
 692                 db2_commit( $this->mConn );
 693
 694                 // Some MediaWiki code is still transaction-less (?).
 695                 // The strategy is to keep AutoCommit on for that code
 696                 //  but switch it off whenever a transaction is begun.
 697                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 698
 699                 $this->mTrxLevel = 0;
 700         }
 701
 702         /**
 703          * Cancel a transaction
 704          */
 705         public function rollback( $fname = 'DatabaseIbm_db2::rollback' ) {
 706                 db2_rollback( $this->mConn );
 707                 // turn auto-commit back on
 708                 // not sure if this is appropriate
 709                 db2_autocommit( $this->mConn, DB2_AUTOCOMMIT_ON );
 710                 $this->mTrxLevel = 0;
 711         }
 712
 713         /**
 714          * Makes an encoded list of strings from an array
 715          * $mode:
 716          *   LIST_COMMA         - comma separated, no field names
 717          *   LIST_AND           - ANDed WHERE clause (without the WHERE)
 718          *   LIST_OR            - ORed WHERE clause (without the WHERE)
 719          *   LIST_SET           - comma separated with field names, like a SET clause
 720          *   LIST_NAMES         - comma separated field names
 721          *   LIST_SET_PREPARED  - like LIST_SET, except with ? tokens as values
 722          */
 723         function makeList( $a, $mode = LIST_COMMA ) {
 724                 if ( !is_array( $a ) ) {
 725                         throw new DBUnexpectedError( $this,
 726                                 'DatabaseIbm_db2::makeList called with incorrect parameters' );
 727                 }
 728
 729                 // if this is for a prepared UPDATE statement
 730                 // (this should be promoted to the parent class
 731                 //  once other databases use prepared statements)
 732                 if ( $mode == LIST_SET_PREPARED ) {
 733                         $first = true;
 734                         $list = '';
 735                         foreach ( $a as $field => $value ) {
 736                                 if ( !$first ) {
 737                                         $list .= ", $field = ?";
 738                                 } else {
 739                                         $list .= "$field = ?";
 740                                         $first = false;
 741                                 }
 742                         }
 743                         $list .= '';
 744
 745                         return $list;
 746                 }
 747
 748                 // otherwise, call the usual function
 749                 return parent::makeList( $a, $mode );
 750         }
 751
 752         /**
 753          * Construct a LIMIT query with optional offset
 754          * This is used for query pages
 755          *
 756          * @param $sql string SQL query we will append the limit too
 757          * @param $limit integer the SQL limit
 758          * @param $offset integer the SQL offset (default false)
 759          */
 760         public function limitResult( $sql, $limit, $offset=false ) {
 761                 if( !is_numeric( $limit ) ) {
 762                         throw new DBUnexpectedError( $this,
 763                                 "Invalid non-numeric limit passed to limitResult()\n" );
 764                 }
 765                 if( $offset ) {
 766                         if ( stripos( $sql, 'where' ) === false ) {
 767                                 return "$sql AND ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 768                         } else {
 769                                 return "$sql WHERE ( ROWNUM BETWEEN $offset AND $offset+$limit )";
 770                         }
 771                 }
 772                 return "$sql FETCH FIRST $limit ROWS ONLY ";
 773         }
 774
 775         /**
 776          * Handle reserved keyword replacement in table names
 777          *
 778          * @param $name Object
 779          * @param $name Boolean
 780          * @return String
 781          */
 782         public function tableName( $name, $quoted = true ) {
 783                 // we want maximum compatibility with MySQL schema
 784                 return $name;
 785         }
 786
 787         /**
 788          * Generates a timestamp in an insertable format
 789          *
 790          * @param $ts timestamp
 791          * @return String: timestamp value
 792          */
 793         public function timestamp( $ts = 0 ) {
 794                 // TS_MW cannot be easily distinguished from an integer
 795                 return wfTimestamp( TS_DB2, $ts );
 796         }
 797
 798         /**
 799          * Return the next in a sequence, save the value for retrieval via insertId()
 800          * @param $seqName String: name of a defined sequence in the database
 801          * @return next value in that sequence
 802          */
 803         public function nextSequenceValue( $seqName ) {
 804                 // Not using sequences in the primary schema to allow for easier migration
 805                 //  from MySQL
 806                 // Emulating MySQL behaviour of using NULL to signal that sequences
 807                 // aren't used
 808                 /*
 809                 $safeseq = preg_replace( "/'/", "''", $seqName );
 810                 $res = $this->query( "VALUES NEXTVAL FOR $safeseq" );
 811                 $row = $this->fetchRow( $res );
 812                 $this->mInsertId = $row[0];
 813                 return $this->mInsertId;
 814                 */
 815                 return null;
 816         }
 817
 818         /**
 819          * This must be called after nextSequenceVal
 820          * @return Last sequence value used as a primary key
 821          */
 822         public function insertId() {
 823                 return $this->mInsertId;
 824         }
 825
 826         /**
 827          * Updates the mInsertId property with the value of the last insert
 828          *  into a generated column
 829          *
 830          * @param $table      String: sanitized table name
 831          * @param $primaryKey Mixed: string name of the primary key
 832          * @param $stmt       Resource: prepared statement resource
 833          *  of the SELECT primary_key FROM FINAL TABLE ( INSERT ... ) form
 834          */
 835         private function calcInsertId( $table, $primaryKey, $stmt ) {
 836                 if ( $primaryKey ) {
 837                         $this->mInsertId = db2_last_insert_id( $this->mConn );
 838                 }
 839         }
 840
 841         /**
 842          * INSERT wrapper, inserts an array into a table
 843          *
 844          * $args may be a single associative array, or an array of arrays
 845          *  with numeric keys, for multi-row insert
 846          *
 847          * @param $table   String: Name of the table to insert to.
 848          * @param $args    Array: Items to insert into the table.
 849          * @param $fname   String: Name of the function, for profiling
 850          * @param $options String or Array. Valid options: IGNORE
 851          *
 852          * @return bool Success of insert operation. IGNORE always returns true.
 853          */
 854         public function insert( $table, $args, $fname = 'DatabaseIbm_db2::insert',
 855                 $options = array() )
 856         {
 857                 if ( !count( $args ) ) {
 858                         return true;
 859                 }
 860                 // get database-specific table name (not used)
 861                 $table = $this->tableName( $table );
 862                 // format options as an array
 863                 $options = IBM_DB2Helper::makeArray( $options );
 864                 // format args as an array of arrays
 865                 if ( !( isset( $args[0] ) && is_array( $args[0] ) ) ) {
 866                         $args = array( $args );
 867                 }
 868
 869                 // prevent insertion of NULL into primary key columns
 870                 list( $args, $primaryKeys ) = $this->removeNullPrimaryKeys( $table, $args );
 871                 // if there's only one primary key
 872                 // we'll be able to read its value after insertion
 873                 $primaryKey = false;
 874                 if ( count( $primaryKeys ) == 1 ) {
 875                         $primaryKey = $primaryKeys[0];
 876                 }
 877
 878                 // get column names
 879                 $keys = array_keys( $args[0] );
 880                 $key_count = count( $keys );
 881
 882                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 883                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
 884
 885                 // assume success
 886                 $res = true;
 887                 // If we are not in a transaction, we need to be for savepoint trickery
 888                 if ( !$this->mTrxLevel ) {
 889                         $this->begin();
 890                 }
 891
 892                 $sql = "INSERT INTO $table ( " . implode( ',', $keys ) . ' ) VALUES ';
 893                 if ( $key_count == 1 ) {
 894                         $sql .= '( ? )';
 895                 } else {
 896                         $sql .= '( ?' . str_repeat( ',?', $key_count-1 ) . ' )';
 897                 }
 898                 $this->installPrint( "Preparing the following SQL:" );
 899                 $this->installPrint( "$sql" );
 900                 $this->installPrint( print_r( $args, true ));
 901                 $stmt = $this->prepare( $sql );
 902
 903                 // start a transaction/enter transaction mode
 904                 $this->begin();
 905
 906                 if ( !$ignore ) {
 907                         //$first = true;
 908                         foreach ( $args as $row ) {
 909                                 //$this->installPrint( "Inserting " . print_r( $row, true ));
 910                                 // insert each row into the database
 911                                 $res = $res & $this->execute( $stmt, $row );
 912                                 if ( !$res ) {
 913                                         $this->installPrint( 'Last error:' );
 914                                         $this->installPrint( $this->lastError() );
 915                                 }
 916                                 // get the last inserted value into a generated column
 917                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 918                         }
 919                 } else {
 920                         $olde = error_reporting( 0 );
 921                         // For future use, we may want to track the number of actual inserts
 922                         // Right now, insert (all writes) simply return true/false
 923                         $numrowsinserted = 0;
 924
 925                         // always return true
 926                         $res = true;
 927
 928                         foreach ( $args as $row ) {
 929                                 $overhead = "SAVEPOINT $ignore ON ROLLBACK RETAIN CURSORS";
 930                                 db2_exec( $this->mConn, $overhead, $this->mStmtOptions );
 931
 932                                 $res2 = $this->execute( $stmt, $row );
 933
 934                                 if ( !$res2 ) {
 935                                         $this->installPrint( 'Last error:' );
 936                                         $this->installPrint( $this->lastError() );
 937                                 }
 938                                 // get the last inserted value into a generated column
 939                                 $this->calcInsertId( $table, $primaryKey, $stmt );
 940
 941                                 $errNum = $this->lastErrno();
 942                                 if ( $errNum ) {
 943                                         db2_exec( $this->mConn, "ROLLBACK TO SAVEPOINT $ignore",
 944                                                 $this->mStmtOptions );
 945                                 } else {
 946                                         db2_exec( $this->mConn, "RELEASE SAVEPOINT $ignore",
 947                                                 $this->mStmtOptions );
 948                                         $numrowsinserted++;
 949                                 }
 950                         }
 951
 952                         $olde = error_reporting( $olde );
 953                         // Set the affected row count for the whole operation
 954                         $this->mAffectedRows = $numrowsinserted;
 955                 }
 956                 // commit either way
 957                 $this->commit();
 958                 $this->freePrepared( $stmt );
 959
 960                 return $res;
 961         }
 962
 963         /**
 964          * Given a table name and a hash of columns with values
 965          * Removes primary key columns from the hash where the value is NULL
 966          *
 967          * @param $table String: name of the table
 968          * @param $args Array of hashes of column names with values
 969          * @return Array: tuple( filtered array of columns, array of primary keys )
 970          */
 971         private function removeNullPrimaryKeys( $table, $args ) {
 972                 $schema = $this->mSchema;
 973
 974                 // find out the primary keys
 975                 $keyres = $this->doQuery( "SELECT NAME FROM SYSIBM.SYSCOLUMNS WHERE TBNAME = '"
 976                   . strtoupper( $table )
 977                   . "' AND TBCREATOR = '"
 978                   . strtoupper( $schema )
 979                   . "' AND KEYSEQ > 0" );
 980
 981                 $keys = array();
 982                 for (
 983                         $row = $this->fetchRow( $keyres );
 984                         $row != null;
 985                         $row = $this->fetchRow( $keyres )
 986                 )
 987                 {
 988                         $keys[] = strtolower( $row[0] );
 989                 }
 990                 // remove primary keys
 991                 foreach ( $args as $ai => $row ) {
 992                         foreach ( $keys as $key ) {
 993                                 if ( $row[$key] == null ) {
 994                                         unset( $row[$key] );
 995                                 }
 996                         }
 997                         $args[$ai] = $row;
 998                 }
 999                 // return modified hash
1000                 return array( $args, $keys );
1001         }
1002
1003         /**
1004          * UPDATE wrapper, takes a condition array and a SET array
1005          *
1006          * @param $table  String: The table to UPDATE
1007          * @param $values An array of values to SET
1008          * @param $conds  An array of conditions ( WHERE ). Use '*' to update all rows.
1009          * @param $fname  String: The Class::Function calling this function
1010          *                ( for the log )
1011          * @param $options An array of UPDATE options, can be one or
1012          *                 more of IGNORE, LOW_PRIORITY
1013          * @return Boolean
1014          */
1015         public function update( $table, $values, $conds, $fname = 'DatabaseIbm_db2::update',
1016                 $options = array() )
1017         {
1018                 $table = $this->tableName( $table );
1019                 $opts = $this->makeUpdateOptions( $options );
1020                 $sql = "UPDATE $opts $table SET "
1021                         . $this->makeList( $values, LIST_SET_PREPARED );
1022                 if ( $conds != '*' ) {
1023                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1024                 }
1025                 $stmt = $this->prepare( $sql );
1026                 $this->installPrint( 'UPDATE: ' . print_r( $values, true ) );
1027                 // assuming for now that an array with string keys will work
1028                 // if not, convert to simple array first
1029                 $result = $this->execute( $stmt, $values );
1030                 $this->freePrepared( $stmt );
1031
1032                 return $result;
1033         }
1034
1035         /**
1036          * DELETE query wrapper
1037          *
1038          * Use $conds == "*" to delete all rows
1039          */
1040         public function delete( $table, $conds, $fname = 'DatabaseIbm_db2::delete' ) {
1041                 if ( !$conds ) {
1042                         throw new DBUnexpectedError( $this,
1043                                 'DatabaseIbm_db2::delete() called with no conditions' );
1044                 }
1045                 $table = $this->tableName( $table );
1046                 $sql = "DELETE FROM $table";
1047                 if ( $conds != '*' ) {
1048                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1049                 }
1050                 $result = $this->query( $sql, $fname );
1051
1052                 return $result;
1053         }
1054
1055         /**
1056          * Returns the number of rows affected by the last query or 0
1057          * @return Integer: the number of rows affected by the last query
1058          */
1059         public function affectedRows() {
1060                 if ( !is_null( $this->mAffectedRows ) ) {
1061                         // Forced result for simulated queries
1062                         return $this->mAffectedRows;
1063                 }
1064                 if( empty( $this->mLastResult ) ) {
1065                         return 0;
1066                 }
1067                 return db2_num_rows( $this->mLastResult );
1068         }
1069
1070         /**
1071          * Simulates REPLACE with a DELETE followed by INSERT
1072          * @param $table Object
1073          * @param $uniqueIndexes Array consisting of indexes and arrays of indexes
1074          * @param $rows Array: rows to insert
1075          * @param $fname String: name of the function for profiling
1076          * @return nothing
1077          */
1078         function replace( $table, $uniqueIndexes, $rows,
1079                 $fname = 'DatabaseIbm_db2::replace' )
1080         {
1081                 $table = $this->tableName( $table );
1082
1083                 if ( count( $rows )==0 ) {
1084                         return;
1085                 }
1086
1087                 # Single row case
1088                 if ( !is_array( reset( $rows ) ) ) {
1089                         $rows = array( $rows );
1090                 }
1091
1092                 foreach( $rows as $row ) {
1093                         # Delete rows which collide
1094                         if ( $uniqueIndexes ) {
1095                                 $sql = "DELETE FROM $table WHERE ";
1096                                 $first = true;
1097                                 foreach ( $uniqueIndexes as $index ) {
1098                                         if ( $first ) {
1099                                                 $first = false;
1100                                                 $sql .= '( ';
1101                                         } else {
1102                                                 $sql .= ' ) OR ( ';
1103                                         }
1104                                         if ( is_array( $index ) ) {
1105                                                 $first2 = true;
1106                                                 foreach ( $index as $col ) {
1107                                                         if ( $first2 ) {
1108                                                                 $first2 = false;
1109                                                         } else {
1110                                                                 $sql .= ' AND ';
1111                                                         }
1112                                                         $sql .= $col . '=' . $this->addQuotes( $row[$col] );
1113                                                 }
1114                                         } else {
1115                                                 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
1116                                         }
1117                                 }
1118                                 $sql .= ' )';
1119                                 $this->query( $sql, $fname );
1120                         }
1121
1122                         # Now insert the row
1123                         $this->insert($table, $row);
1124                 }
1125         }
1126
1127         /**
1128          * Returns the number of rows in the result set
1129          * Has to be called right after the corresponding select query
1130          * @param $res Object result set
1131          * @return Integer: number of rows
1132          */
1133         public function numRows( $res ) {
1134                 if ( $res instanceof ResultWrapper ) {
1135                         $res = $res->result;
1136                 }
1137
1138                 if ( $this->mNumRows ) {
1139                         return $this->mNumRows;
1140                 } else {
1141                         return 0;
1142                 }
1143         }
1144
1145         /**
1146          * Moves the row pointer of the result set
1147          * @param $res Object: result set
1148          * @param $row Integer: row number
1149          * @return success or failure
1150          */
1151         public function dataSeek( $res, $row ) {
1152                 if ( $res instanceof ResultWrapper ) {
1153                         $res = $res->result;
1154                 }
1155                 return db2_fetch_row( $res, $row );
1156         }
1157
1158         ###
1159         # Fix notices in Block.php
1160         ###
1161
1162         /**
1163          * Frees memory associated with a statement resource
1164          * @param $res Object: statement resource to free
1165          * @return Boolean success or failure
1166          */
1167         public function freeResult( $res ) {
1168                 if ( $res instanceof ResultWrapper ) {
1169                         $res = $res->result;
1170                 }
1171                 if ( !@db2_free_result( $res ) ) {
1172                         throw new DBUnexpectedError( $this, "Unable to free DB2 result\n" );
1173                 }
1174         }
1175
1176         /**
1177          * Returns the number of columns in a resource
1178          * @param $res Object: statement resource
1179          * @return Number of fields/columns in resource
1180          */
1181         public function numFields( $res ) {
1182                 if ( $res instanceof ResultWrapper ) {
1183                         $res = $res->result;
1184                 }
1185                 return db2_num_fields( $res );
1186         }
1187
1188         /**
1189          * Returns the nth column name
1190          * @param $res Object: statement resource
1191          * @param $n Integer: Index of field or column
1192          * @return String name of nth column
1193          */
1194         public function fieldName( $res, $n ) {
1195                 if ( $res instanceof ResultWrapper ) {
1196                         $res = $res->result;
1197                 }
1198                 return db2_field_name( $res, $n );
1199         }
1200
1201         /**
1202          * SELECT wrapper
1203          *
1204          * @param $table   Array or string, table name(s) (prefix auto-added)
1205          * @param $vars    Array or string, field name(s) to be retrieved
1206          * @param $conds   Array or string, condition(s) for WHERE
1207          * @param $fname   String: calling function name (use __METHOD__)
1208          *                 for logs/profiling
1209          * @param $options Associative array of options
1210          *                 (e.g. array('GROUP BY' => 'page_title')),
1211          *                 see Database::makeSelectOptions code for list of
1212          *                 supported stuff
1213          * @param $join_conds Associative array of table join conditions (optional)
1214          *                    (e.g. array( 'page' => array('LEFT JOIN',
1215          *                    'page_latest=rev_id') )
1216          * @return Mixed: database result resource for fetch functions or false
1217          *                 on failure
1218          */
1219         public function select( $table, $vars, $conds = '', $fname = 'DatabaseIbm_db2::select', $options = array(), $join_conds = array() )
1220         {
1221                 $res = parent::select( $table, $vars, $conds, $fname, $options,
1222                         $join_conds );
1223
1224                 // We must adjust for offset
1225                 if ( isset( $options['LIMIT'] ) && isset ( $options['OFFSET'] ) ) {
1226                         $limit = $options['LIMIT'];
1227                         $offset = $options['OFFSET'];
1228                 }
1229
1230                 // DB2 does not have a proper num_rows() function yet, so we must emulate
1231                 // DB2 9.5.4 and the corresponding ibm_db2 driver will introduce
1232                 //  a working one
1233                 // TODO: Yay!
1234
1235                 // we want the count
1236                 $vars2 = array( 'count( * ) as num_rows' );
1237                 // respecting just the limit option
1238                 $options2 = array();
1239                 if ( isset( $options['LIMIT'] ) ) {
1240                         $options2['LIMIT'] = $options['LIMIT'];
1241                 }
1242                 // but don't try to emulate for GROUP BY
1243                 if ( isset( $options['GROUP BY'] ) ) {
1244                         return $res;
1245                 }
1246
1247                 $res2 = parent::select( $table, $vars2, $conds, $fname, $options2,
1248                         $join_conds );
1249                 $obj = $this->fetchObject( $res2 );
1250                 $this->mNumRows = $obj->num_rows;
1251
1252                 return $res;
1253         }
1254
1255         /**
1256          * Handles ordering, grouping, and having options ('GROUP BY' => colname)
1257          * Has limited support for per-column options (colnum => 'DISTINCT')
1258          *
1259          * @private
1260          *
1261          * @param $options Associative array of options to be turned into
1262          *              an SQL query, valid keys are listed in the function.
1263          * @return Array
1264          */
1265         function makeSelectOptions( $options ) {
1266                 $preLimitTail = $postLimitTail = '';
1267                 $startOpts = '';
1268
1269                 $noKeyOptions = array();
1270                 foreach ( $options as $key => $option ) {
1271                         if ( is_numeric( $key ) ) {
1272                                 $noKeyOptions[$option] = true;
1273                         }
1274                 }
1275
1276                 if ( isset( $options['GROUP BY'] ) ) {
1277                         $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1278                 }
1279                 if ( isset( $options['HAVING'] ) ) {
1280                         $preLimitTail .= " HAVING {$options['HAVING']}";
1281                 }
1282                 if ( isset( $options['ORDER BY'] ) ) {
1283                         $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1284                 }
1285
1286                 if ( isset( $noKeyOptions['DISTINCT'] )
1287                         || isset( $noKeyOptions['DISTINCTROW'] ) )
1288                 {
1289                         $startOpts .= 'DISTINCT';
1290                 }
1291
1292                 return array( $startOpts, '', $preLimitTail, $postLimitTail );
1293         }
1294
1295         /**
1296          * Returns link to IBM DB2 free download
1297          * @return String: wikitext of a link to the server software's web site
1298          */
1299         public static function getSoftwareLink() {
1300                 return '[http://www.ibm.com/db2/express/ IBM DB2]';
1301         }
1302
1303         /**
1304          * Get search engine class. All subclasses of this
1305          * need to implement this if they wish to use searching.
1306          *
1307          * @return String
1308          */
1309         public function getSearchEngine() {
1310                 return 'SearchIBM_DB2';
1311         }
1312
1313         /**
1314          * Did the last database access fail because of deadlock?
1315          * @return Boolean
1316          */
1317         public function wasDeadlock() {
1318                 // get SQLSTATE
1319                 $err = $this->lastErrno();
1320                 switch( $err ) {
1321                         // This is literal port of the MySQL logic and may be wrong for DB2
1322                         case '40001':   // sql0911n, Deadlock or timeout, rollback
1323                         case '57011':   // sql0904n, Resource unavailable, no rollback
1324                         case '57033':   // sql0913n, Deadlock or timeout, no rollback
1325                         $this->installPrint( "In a deadlock because of SQLSTATE $err" );
1326                         return true;
1327                 }
1328                 return false;
1329         }
1330
1331         /**
1332          * Ping the server and try to reconnect if it there is no connection
1333          * The connection may be closed and reopened while this happens
1334          * @return Boolean: whether the connection exists
1335          */
1336         public function ping() {
1337                 // db2_ping() doesn't exist
1338                 // Emulate
1339                 $this->close();
1340                 $this->mConn = $this->openUncataloged( $this->mDBName, $this->mUser,
1341                         $this->mPassword, $this->mServer, $this->mPort );
1342
1343                 return false;
1344         }
1345         ######################################
1346         # Unimplemented and not applicable
1347         ######################################
1348         /**
1349          * Not implemented
1350          * @return string ''
1351          */
1352         public function getStatus( $which = '%' ) {
1353                 $this->installPrint( 'Not implemented for DB2: getStatus()' );
1354                 return '';
1355         }
1356         /**
1357          * Not implemented
1358          * @return string $sql
1359          */
1360         public function limitResultForUpdate( $sql, $num ) {
1361                 $this->installPrint( 'Not implemented for DB2: limitResultForUpdate()' );
1362                 return $sql;
1363         }
1364
1365         /**
1366          * Only useful with fake prepare like in base Database class
1367          * @return      string
1368          */
1369         public function fillPreparedArg( $matches ) {
1370                 $this->installPrint( 'Not useful for DB2: fillPreparedArg()' );
1371                 return '';
1372         }
1373
1374         ######################################
1375         # Reflection
1376         ######################################
1377
1378         /**
1379          * Returns information about an index
1380          * If errors are explicitly ignored, returns NULL on failure
1381          * @param $table String: table name
1382          * @param $index String: index name
1383          * @param $fname String: function name for logging and profiling
1384          * @return Object query row in object form
1385          */
1386         public function indexInfo( $table, $index,
1387                 $fname = 'DatabaseIbm_db2::indexExists' )
1388         {
1389                 $table = $this->tableName( $table );
1390                 $sql = <<<SQL
1391 SELECT name as indexname
1392 FROM sysibm.sysindexes si
1393 WHERE si.name='$index' AND si.tbname='$table'
1394 AND sc.tbcreator='$this->mSchema'
1395 SQL;
1396                 $res = $this->query( $sql, $fname );
1397                 if ( !$res ) {
1398                         return null;
1399                 }
1400                 $row = $this->fetchObject( $res );
1401                 if ( $row != null ) {
1402                         return $row;
1403                 } else {
1404                         return false;
1405                 }
1406         }
1407
1408         /**
1409          * Returns an information object on a table column
1410          * @param $table String: table name
1411          * @param $field String: column name
1412          * @return IBM_DB2Field
1413          */
1414         public function fieldInfo( $table, $field ) {
1415                 return IBM_DB2Field::fromText( $this, $table, $field );
1416         }
1417
1418         /**
1419          * db2_field_type() wrapper
1420          * @param $res Object: result of executed statement
1421          * @param $index Mixed: number or name of the column
1422          * @return String column type
1423          */
1424         public function fieldType( $res, $index ) {
1425                 if ( $res instanceof ResultWrapper ) {
1426                         $res = $res->result;
1427                 }
1428                 return db2_field_type( $res, $index );
1429         }
1430
1431         /**
1432          * Verifies that an index was created as unique
1433          * @param $table String: table name
1434          * @param $index String: index name
1435          * @param $fname function name for profiling
1436          * @return Bool
1437          */
1438         public function indexUnique ( $table, $index,
1439                 $fname = 'DatabaseIbm_db2::indexUnique' )
1440         {
1441                 $table = $this->tableName( $table );
1442                 $sql = <<<SQL
1443 SELECT si.name as indexname
1444 FROM sysibm.sysindexes si
1445 WHERE si.name='$index' AND si.tbname='$table'
1446 AND sc.tbcreator='$this->mSchema'
1447 AND si.uniquerule IN ( 'U', 'P' )
1448 SQL;
1449                 $res = $this->query( $sql, $fname );
1450                 if ( !$res ) {
1451                         return null;
1452                 }
1453                 if ( $this->fetchObject( $res ) ) {
1454                         return true;
1455                 }
1456                 return false;
1457
1458         }
1459
1460         /**
1461          * Returns the size of a text field, or -1 for "unlimited"
1462          * @param $table String: table name
1463          * @param $field String: column name
1464          * @return Integer: length or -1 for unlimited
1465          */
1466         public function textFieldSize( $table, $field ) {
1467                 $table = $this->tableName( $table );
1468                 $sql = <<<SQL
1469 SELECT length as size
1470 FROM sysibm.syscolumns sc
1471 WHERE sc.name='$field' AND sc.tbname='$table'
1472 AND sc.tbcreator='$this->mSchema'
1473 SQL;
1474                 $res = $this->query( $sql );
1475                 $row = $this->fetchObject( $res );
1476                 $size = $row->size;
1477                 return $size;
1478         }
1479
1480         /**
1481          * Description is left as an exercise for the reader
1482          * @param $b Mixed: data to be encoded
1483          * @return IBM_DB2Blob
1484          */
1485         public function encodeBlob( $b ) {
1486                 return new IBM_DB2Blob( $b );
1487         }
1488
1489         /**
1490          * Description is left as an exercise for the reader
1491          * @param $b IBM_DB2Blob: data to be decoded
1492          * @return mixed
1493          */
1494         public function decodeBlob( $b ) {
1495                 return "$b";
1496         }
1497
1498         /**
1499          * Convert into a list of string being concatenated
1500          * @param $stringList Array: strings that need to be joined together
1501          *                    by the SQL engine
1502          * @return String: joined by the concatenation operator
1503          */
1504         public function buildConcat( $stringList ) {
1505                 // || is equivalent to CONCAT
1506                 // Sample query: VALUES 'foo' CONCAT 'bar' CONCAT 'baz'
1507                 return implode( ' || ', $stringList );
1508         }
1509
1510         /**
1511          * Generates the SQL required to convert a DB2 timestamp into a Unix epoch
1512          * @param $column String: name of timestamp column
1513          * @return String: SQL code
1514          */
1515         public function extractUnixEpoch( $column ) {
1516                 // TODO
1517                 // see SpecialAncientpages
1518         }
1519
1520         ######################################
1521         # Prepared statements
1522         ######################################
1523
1524         /**
1525          * Intended to be compatible with the PEAR::DB wrapper functions.
1526          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1527          *
1528          * ? = scalar value, quoted as necessary
1529          * ! = raw SQL bit (a function for instance)
1530          * & = filename; reads the file and inserts as a blob
1531          *     (we don't use this though...)
1532          * @param $sql String: SQL statement with appropriate markers
1533          * @param $func String: Name of the function, for profiling
1534          * @return resource a prepared DB2 SQL statement
1535          */
1536         public function prepare( $sql, $func = 'DB2::prepare' ) {
1537                 $stmt = db2_prepare( $this->mConn, $sql, $this->mStmtOptions );
1538                 return $stmt;
1539         }
1540
1541         /**
1542          * Frees resources associated with a prepared statement
1543          * @return Boolean success or failure
1544          */
1545         public function freePrepared( $prepared ) {
1546                 return db2_free_stmt( $prepared );
1547         }
1548
1549         /**
1550          * Execute a prepared query with the various arguments
1551          * @param $prepared String: the prepared sql
1552          * @param $args Mixed: either an array here, or put scalars as varargs
1553          * @return Resource: results object
1554          */
1555         public function execute( $prepared, $args = null ) {
1556                 if( !is_array( $args ) ) {
1557                         # Pull the var args
1558                         $args = func_get_args();
1559                         array_shift( $args );
1560                 }
1561                 $res = db2_execute( $prepared, $args );
1562                 if ( !$res ) {
1563                         $this->installPrint( db2_stmt_errormsg() );
1564                 }
1565                 return $res;
1566         }
1567
1568         /**
1569          * Prepare & execute an SQL statement, quoting and inserting arguments
1570          * in the appropriate places.
1571          * @param $query String
1572          * @param $args ...
1573          */
1574         public function safeQuery( $query, $args = null ) {
1575                 // copied verbatim from Database.php
1576                 $prepared = $this->prepare( $query, 'DB2::safeQuery' );
1577                 if( !is_array( $args ) ) {
1578                         # Pull the var args
1579                         $args = func_get_args();
1580                         array_shift( $args );
1581                 }
1582                 $retval = $this->execute( $prepared, $args );
1583                 $this->freePrepared( $prepared );
1584                 return $retval;
1585         }
1586
1587         /**
1588          * For faking prepared SQL statements on DBs that don't support
1589          * it directly.
1590          * @param $preparedQuery String: a 'preparable' SQL statement
1591          * @param $args Array of arguments to fill it with
1592          * @return String: executable statement
1593          */
1594         public function fillPrepared( $preparedQuery, $args ) {
1595                 reset( $args );
1596                 $this->preparedArgs =& $args;
1597
1598                 foreach ( $args as $i => $arg ) {
1599                         db2_bind_param( $preparedQuery, $i+1, $args[$i] );
1600                 }
1601
1602                 return $preparedQuery;
1603         }
1604
1605         /**
1606          * Switches module between regular and install modes
1607          */
1608         public function setMode( $mode ) {
1609                 $old = $this->mMode;
1610                 $this->mMode = $mode;
1611                 return $old;
1612         }
1613
1614         /**
1615          * Bitwise negation of a column or value in SQL
1616          * Same as (~field) in C
1617          * @param $field String
1618          * @return String
1619          */
1620         function bitNot( $field ) {
1621                 // expecting bit-fields smaller than 4bytes
1622                 return "BITNOT( $field )";
1623         }
1624
1625         /**
1626          * Bitwise AND of two columns or values in SQL
1627          * Same as (fieldLeft & fieldRight) in C
1628          * @param $fieldLeft String
1629          * @param $fieldRight String
1630          * @return String
1631          */
1632         function bitAnd( $fieldLeft, $fieldRight ) {
1633                 return "BITAND( $fieldLeft, $fieldRight )";
1634         }
1635
1636         /**
1637          * Bitwise OR of two columns or values in SQL
1638          * Same as (fieldLeft | fieldRight) in C
1639          * @param $fieldLeft String
1640          * @param $fieldRight String
1641          * @return String
1642          */
1643         function bitOr( $fieldLeft, $fieldRight ) {
1644                 return "BITOR( $fieldLeft, $fieldRight )";
1645         }
1646 }
1647
1648 class IBM_DB2Helper {
1649         public static function makeArray( $maybeArray ) {
1650                 if ( !is_array( $maybeArray ) ) {
1651                         return array( $maybeArray );
1652                 }
1653
1654                 return $maybeArray;
1655         }
1656 }