includes/db/DatabaseSqlite.php

   1 <?php
   2 /**
   3  * This is the SQLite database abstraction layer.
   4  * See maintenance/sqlite/README for development notes and other specific information
   5  *
   6  * @file
   7  * @ingroup Database
   8  */
   9
  10 /**
  11  * @ingroup Database
  12  */
  13 class DatabaseSqlite extends DatabaseBase {
  14
  15         private static $fulltextEnabled = null;
  16
  17         var $mAffectedRows;
  18         var $mLastResult;
  19         var $mDatabaseFile;
  20         var $mName;
  21
  22         /**
  23          * Constructor.
  24          * Parameters $server, $user and $password are not used.
  25          */
  26         function __construct( $server = false, $user = false, $password = false, $dbName = false, $flags = 0 ) {
  27                 $this->mName = $dbName;
  28                 parent::__construct( $server, $user, $password, $dbName, $flags );
  29                 // parent doesn't open when $user is false, but we can work with $dbName
  30                 if( !$user && $dbName ) {
  31                         global $wgSharedDB;
  32                         if( $this->open( $server, $user, $password, $dbName ) && $wgSharedDB ) {
  33                                 $this->attachDatabase( $wgSharedDB );
  34                         }
  35                 }
  36         }
  37
  38         function getType() {
  39                 return 'sqlite';
  40         }
  41
  42         /**
  43          * @todo: check if it should be true like parent class
  44          */
  45         function implicitGroupby()   { return false; }
  46
  47         /** Open an SQLite database and return a resource handle to it
  48          *  NOTE: only $dbName is used, the other parameters are irrelevant for SQLite databases
  49          */
  50         function open( $server, $user, $pass, $dbName ) {
  51                 global $wgSQLiteDataDir;
  52
  53                 $fileName = self::generateFileName( $wgSQLiteDataDir, $dbName );
  54                 if ( !is_readable( $fileName ) ) {
  55                         $this->mConn = false;
  56                         throw new DBConnectionError( $this, "SQLite database not accessible" );
  57                 }
  58                 $this->openFile( $fileName );
  59                 return $this->mConn;
  60         }
  61
  62         /**
  63          * Opens a database file
  64          * @return SQL connection or false if failed
  65          */
  66         function openFile( $fileName ) {
  67                 $this->mDatabaseFile = $fileName;
  68                 try {
  69                         if ( $this->mFlags & DBO_PERSISTENT ) {
  70                                 $this->mConn = new PDO( "sqlite:$fileName", '', '',
  71                                         array( PDO::ATTR_PERSISTENT => true ) );
  72                         } else {
  73                                 $this->mConn = new PDO( "sqlite:$fileName", '', '' );
  74                         }
  75                 } catch ( PDOException $e ) {
  76                         $err = $e->getMessage();
  77                 }
  78                 if ( !$this->mConn ) {
  79                         wfDebug( "DB connection error: $err\n" );
  80                         throw new DBConnectionError( $this, $err );
  81                 }
  82                 $this->mOpened = !!$this->mConn;
  83                 # set error codes only, don't raise exceptions
  84                 if ( $this->mOpened ) {
  85                         $this->mConn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
  86                         return true;
  87                 }
  88         }
  89
  90         /**
  91          * Close an SQLite database
  92          */
  93         function close() {
  94                 $this->mOpened = false;
  95                 if ( is_object( $this->mConn ) ) {
  96                         if ( $this->trxLevel() ) $this->commit();
  97                         $this->mConn = null;
  98                 }
  99                 return true;
 100         }
 101
 102         /**
 103          * Generates a database file name. Explicitly public for installer.
 104          * @param $dir String: Directory where database resides
 105          * @param $dbName String: Database name
 106          * @return String
 107          */
 108         public static function generateFileName( $dir, $dbName ) {
 109                 return "$dir/$dbName.sqlite";
 110         }
 111
 112         /**
 113          * Check if the searchindext table is FTS enabled.
 114          * @returns false if not enabled.
 115          */
 116         function checkForEnabledSearch() {
 117                 if ( self::$fulltextEnabled === null ) {
 118                         self::$fulltextEnabled = false;
 119                         $table = $this->tableName( 'searchindex' );
 120                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 121                         if ( $res ) {
 122                                 $row = $res->fetchRow();
 123                                 self::$fulltextEnabled = stristr($row['sql'], 'fts' ) !== false;
 124                         }
 125                 }
 126                 return self::$fulltextEnabled;
 127         }
 128
 129         /**
 130          * Returns version of currently supported SQLite fulltext search module or false if none present.
 131          * @return String
 132          */
 133         static function getFulltextSearchModule() {
 134                 static $cachedResult = null;
 135                 if ( $cachedResult !== null ) {
 136                         return $cachedResult;
 137                 }
 138                 $cachedResult = false;
 139                 $table = 'dummy_search_test';
 140
 141                 $db = new DatabaseSqliteStandalone( ':memory:' );
 142
 143                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 144                         $cachedResult = 'FTS3';
 145                 }
 146                 $db->close();
 147                 return $cachedResult;
 148         }
 149
 150         /**
 151          * Attaches external database to our connection, see http://sqlite.org/lang_attach.html
 152          * for details.
 153          * @param $name String: database name to be used in queries like SELECT foo FROM dbname.table
 154          * @param $file String: database file name. If omitted, will be generated using $name and $wgSQLiteDataDir
 155          * @param $fname String: calling function name
 156          */
 157         function attachDatabase( $name, $file = false, $fname = 'DatabaseSqlite::attachDatabase' ) {
 158                 global $wgSQLiteDataDir;
 159                 if ( !$file ) {
 160                         $file = self::generateFileName( $wgSQLiteDataDir, $name );
 161                 }
 162                 $file = $this->addQuotes( $file );
 163                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 164         }
 165
 166         /**
 167          * @see DatabaseBase::isWriteQuery()
 168          */
 169         function isWriteQuery( $sql ) {
 170                 return parent::isWriteQuery( $sql ) && !preg_match( '/^ATTACH\b/i', $sql );
 171         }
 172
 173         /**
 174          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 175          */
 176         function doQuery( $sql ) {
 177                 $res = $this->mConn->query( $sql );
 178                 if ( $res === false ) {
 179                         return false;
 180                 } else {
 181                         $r = $res instanceof ResultWrapper ? $res->result : $res;
 182                         $this->mAffectedRows = $r->rowCount();
 183                         $res = new ResultWrapper( $this, $r->fetchAll() );
 184                 }
 185                 return $res;
 186         }
 187
 188         function freeResult( $res ) {
 189                 if ( $res instanceof ResultWrapper ) {
 190                         $res->result = null;
 191                 } else {
 192                         $res = null;
 193                 }
 194         }
 195
 196         function fetchObject( $res ) {
 197                 if ( $res instanceof ResultWrapper ) {
 198                         $r =& $res->result;
 199                 } else {
 200                         $r =& $res;
 201                 }
 202
 203                 $cur = current( $r );
 204                 if ( is_array( $cur ) ) {
 205                         next( $r );
 206                         $obj = new stdClass;
 207                         foreach ( $cur as $k => $v ) {
 208                                 if ( !is_numeric( $k ) ) {
 209                                         $obj->$k = $v;
 210                                 }
 211                         }
 212
 213                         return $obj;
 214                 }
 215                 return false;
 216         }
 217
 218         function fetchRow( $res ) {
 219                 if ( $res instanceof ResultWrapper ) {
 220                         $r =& $res->result;
 221                 } else {
 222                         $r =& $res;
 223                 }
 224                 $cur = current( $r );
 225                 if ( is_array( $cur ) ) {
 226                         next( $r );
 227                         return $cur;
 228                 }
 229                 return false;
 230         }
 231
 232         /**
 233          * The PDO::Statement class implements the array interface so count() will work
 234          */
 235         function numRows( $res ) {
 236                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 237                 return count( $r );
 238         }
 239
 240         function numFields( $res ) {
 241                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 242                 return is_array( $r ) ? count( $r[0] ) : 0;
 243         }
 244
 245         function fieldName( $res, $n ) {
 246                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 247                 if ( is_array( $r ) ) {
 248                         $keys = array_keys( $r[0] );
 249                         return $keys[$n];
 250                 }
 251                 return  false;
 252         }
 253
 254         /**
 255          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 256          */
 257         function tableName( $name ) {
 258                 // table names starting with sqlite_ are reserved
 259                 if ( strpos( $name, 'sqlite_' ) === 0 ) return $name;
 260                 return str_replace( '`', '', parent::tableName( $name ) );
 261         }
 262
 263         /**
 264          * Index names have DB scope
 265          */
 266         function indexName( $index ) {
 267                 return $index;
 268         }
 269
 270         /**
 271          * This must be called after nextSequenceVal
 272          */
 273         function insertId() {
 274                 return $this->mConn->lastInsertId();
 275         }
 276
 277         function dataSeek( $res, $row ) {
 278                 if ( $res instanceof ResultWrapper ) {
 279                         $r =& $res->result;
 280                 } else {
 281                         $r =& $res;
 282                 }
 283                 reset( $r );
 284                 if ( $row > 0 ) {
 285                         for ( $i = 0; $i < $row; $i++ ) {
 286                                 next( $r );
 287                         }
 288                 }
 289         }
 290
 291         function lastError() {
 292                 if ( !is_object( $this->mConn ) ) {
 293                         return "Cannot return last error, no db connection";
 294                 }
 295                 $e = $this->mConn->errorInfo();
 296                 return isset( $e[2] ) ? $e[2] : '';
 297         }
 298
 299         function lastErrno() {
 300                 if ( !is_object( $this->mConn ) ) {
 301                         return "Cannot return last error, no db connection";
 302                 } else {
 303                         $info = $this->mConn->errorInfo();
 304                         return $info[1];
 305                 }
 306         }
 307
 308         function affectedRows() {
 309                 return $this->mAffectedRows;
 310         }
 311
 312         /**
 313          * Returns information about an index
 314          * Returns false if the index does not exist
 315          * - if errors are explicitly ignored, returns NULL on failure
 316          */
 317         function indexInfo( $table, $index, $fname = 'DatabaseSqlite::indexExists' ) {
 318                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 319                 $res = $this->query( $sql, $fname );
 320                 if ( !$res ) {
 321                         return null;
 322                 }
 323                 if ( $res->numRows() == 0 ) {
 324                         return false;
 325                 }
 326                 $info = array();
 327                 foreach ( $res as $row ) {
 328                         $info[] = $row->name;
 329                 }
 330                 return $info;
 331         }
 332
 333         function indexUnique( $table, $index, $fname = 'DatabaseSqlite::indexUnique' ) {
 334                 $row = $this->selectRow( 'sqlite_master', '*',
 335                         array(
 336                                 'type' => 'index',
 337                                 'name' => $this->indexName( $index ),
 338                         ), $fname );
 339                 if ( !$row || !isset( $row->sql ) ) {
 340                         return null;
 341                 }
 342
 343                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 344                 $indexPos = strpos( $row->sql, 'INDEX' );
 345                 if ( $indexPos === false ) {
 346                         return null;
 347                 }
 348                 $firstPart = substr( $row->sql, 0, $indexPos );
 349                 $options = explode( ' ', $firstPart );
 350                 return in_array( 'UNIQUE', $options );
 351         }
 352
 353         /**
 354          * Filter the options used in SELECT statements
 355          */
 356         function makeSelectOptions( $options ) {
 357                 foreach ( $options as $k => $v ) {
 358                         if ( is_numeric( $k ) && $v == 'FOR UPDATE' ) {
 359                                 $options[$k] = '';
 360                         }
 361                 }
 362                 return parent::makeSelectOptions( $options );
 363         }
 364
 365         /**
 366          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 367          */
 368         function insert( $table, $a, $fname = 'DatabaseSqlite::insert', $options = array() ) {
 369                 if ( !count( $a ) ) {
 370                         return true;
 371                 }
 372                 if ( !is_array( $options ) ) {
 373                         $options = array( $options );
 374                 }
 375
 376                 # SQLite uses OR IGNORE not just IGNORE
 377                 foreach ( $options as $k => $v ) {
 378                         if ( $v == 'IGNORE' ) {
 379                                 $options[$k] = 'OR IGNORE';
 380                         }
 381                 }
 382
 383                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 384                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 385                         $ret = true;
 386                         foreach ( $a as $v ) {
 387                                 if ( !parent::insert( $table, $v, "$fname/multi-row", $options ) ) {
 388                                         $ret = false;
 389                                 }
 390                         }
 391                 } else {
 392                         $ret = parent::insert( $table, $a, "$fname/single-row", $options );
 393                 }
 394
 395                 return $ret;
 396         }
 397
 398         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseSqlite::replace' ) {
 399                 if ( !count( $rows ) ) return true;
 400
 401                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 402                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 403                         $ret = true;
 404                         foreach ( $rows as $v ) {
 405                                 if ( !parent::replace( $table, $uniqueIndexes, $v, "$fname/multi-row" ) ) {
 406                                         $ret = false;
 407                                 }
 408                         }
 409                 } else {
 410                         $ret = parent::replace( $table, $uniqueIndexes, $rows, "$fname/single-row" );
 411                 }
 412
 413                 return $ret;
 414         }
 415
 416         /**
 417          * Returns the size of a text field, or -1 for "unlimited"
 418          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 419          */
 420         function textFieldSize( $table, $field ) {
 421                 return -1;
 422         }
 423
 424         function unionSupportsOrderAndLimit() {
 425                 return false;
 426         }
 427
 428         function unionQueries( $sqls, $all ) {
 429                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 430                 return implode( $glue, $sqls );
 431         }
 432
 433         function wasDeadlock() {
 434                 return $this->lastErrno() == 5; // SQLITE_BUSY
 435         }
 436
 437         function wasErrorReissuable() {
 438                 return $this->lastErrno() ==  17; // SQLITE_SCHEMA;
 439         }
 440
 441         function wasReadOnlyError() {
 442                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 443         }
 444
 445         /**
 446          * @return string wikitext of a link to the server software's web site
 447          */
 448         public static function getSoftwareLink() {
 449                 return "[http://sqlite.org/ SQLite]";
 450         }
 451
 452         /**
 453          * @return string Version information from the database
 454          */
 455         function getServerVersion() {
 456                 $ver = $this->mConn->getAttribute( PDO::ATTR_SERVER_VERSION );
 457                 return $ver;
 458         }
 459
 460         /**
 461          * @return string User-friendly database information
 462          */
 463         public function getServerInfo() {
 464                 return wfMsg( self::getFulltextSearchModule() ? 'sqlite-has-fts' : 'sqlite-no-fts', $this->getServerVersion() );
 465         }
 466
 467         /**
 468          * Get information about a given field
 469          * Returns false if the field does not exist.
 470          */
 471         function fieldInfo( $table, $field ) {
 472                 $tableName = $this->tableName( $table );
 473                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 474                 $res = $this->query( $sql, __METHOD__ );
 475                 foreach ( $res as $row ) {
 476                         if ( $row->name == $field ) {
 477                                 return new SQLiteField( $row, $tableName );
 478                         }
 479                 }
 480                 return false;
 481         }
 482
 483         function begin( $fname = '' ) {
 484                 if ( $this->mTrxLevel == 1 ) $this->commit();
 485                 $this->mConn->beginTransaction();
 486                 $this->mTrxLevel = 1;
 487         }
 488
 489         function commit( $fname = '' ) {
 490                 if ( $this->mTrxLevel == 0 ) return;
 491                 $this->mConn->commit();
 492                 $this->mTrxLevel = 0;
 493         }
 494
 495         function rollback( $fname = '' ) {
 496                 if ( $this->mTrxLevel == 0 ) return;
 497                 $this->mConn->rollBack();
 498                 $this->mTrxLevel = 0;
 499         }
 500
 501         function limitResultForUpdate( $sql, $num ) {
 502                 return $this->limitResult( $sql, $num );
 503         }
 504
 505         function strencode( $s ) {
 506                 return substr( $this->addQuotes( $s ), 1, - 1 );
 507         }
 508
 509         function encodeBlob( $b ) {
 510                 return new Blob( $b );
 511         }
 512
 513         function decodeBlob( $b ) {
 514                 if ( $b instanceof Blob ) {
 515                         $b = $b->fetch();
 516                 }
 517                 return $b;
 518         }
 519
 520         function addQuotes( $s ) {
 521                 if ( $s instanceof Blob ) {
 522                         return "x'" . bin2hex( $s->fetch() ) . "'";
 523                 } else {
 524                         return $this->mConn->quote( $s );
 525                 }
 526         }
 527
 528         function buildLike() {
 529                 $params = func_get_args();
 530                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
 531                         $params = $params[0];
 532                 }
 533                 return parent::buildLike( $params ) . "ESCAPE '\' ";
 534         }
 535
 536         public function getSearchEngine() {
 537                 return "SearchSqlite";
 538         }
 539
 540         /**
 541          * No-op version of deadlockLoop
 542          */
 543         public function deadlockLoop( /*...*/ ) {
 544                 $args = func_get_args();
 545                 $function = array_shift( $args );
 546                 return call_user_func_array( $function, $args );
 547         }
 548
 549         protected function replaceVars( $s ) {
 550                 $s = parent::replaceVars( $s );
 551                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 552                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 553
 554                         // binary/varbinary column type -> blob
 555                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 556                         // no such thing as unsigned
 557                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 558                         // INT -> INTEGER
 559                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 560                         // floating point types -> REAL
 561                         $s = preg_replace( '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i', 'REAL', $s );
 562                         // varchar -> TEXT
 563                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 564                         // TEXT normalization
 565                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 566                         // BLOB normalization
 567                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 568                         // BOOL -> INTEGER
 569                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 570                         // DATETIME -> TEXT
 571                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 572                         // No ENUM type
 573                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 574                         // binary collation type -> nothing
 575                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 576                         // auto_increment -> autoincrement
 577                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 578                         // No explicit options
 579                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 580                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 581                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 582                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 583                         // No truncated indexes
 584                         $s = preg_replace( '/\(\d+\)/', '', $s );
 585                         // No FULLTEXT
 586                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 587                 }
 588                 return $s;
 589         }
 590
 591         /*
 592          * Build a concatenation list to feed into a SQL query
 593          */
 594         function buildConcat( $stringList ) {
 595                 return '(' . implode( ') || (', $stringList ) . ')';
 596         }
 597
 598         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabaseSqlite::duplicateTableStructure' ) {
 599
 600                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name='$oldName' AND type='table'", $fname );
 601                 $obj = $this->fetchObject( $res );
 602                 if ( !$obj ) {
 603                         throw new MWException( "Couldn't retrieve structure for table $oldName" );
 604                 }
 605                 $sql = $obj->sql;
 606                 $sql = preg_replace( '/\b' . preg_quote( $oldName ) . '\b/', $newName, $sql, 1 );
 607                 if ( $temporary ) {
 608                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
 609                                 wfDebug( "Table $oldName is virtual, can't create a temporary duplicate.\n" );
 610                         } else {
 611                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
 612                         }
 613                 }
 614                 return $this->query( $sql, $fname );
 615         }
 616
 617
 618         /**
 619          * List all tables on the database
 620          *
 621          * @param $prefix Only show tables with this prefix, e.g. mw_
 622          * @param $fname String: calling function name
 623          */
 624         function listTables( $prefix = null, $fname = 'DatabaseSqlite::listTables' ) {
 625                 $result = $this->select(
 626                         'sqlite_master',
 627                         'name',
 628                         "type='table'"
 629                 );
 630
 631                 $endArray = array();
 632
 633                 foreach( $result as $table ) {
 634                         $vars = get_object_vars($table);
 635                         $table = array_pop( $vars );
 636
 637                         if( !$prefix || strpos( $table, $prefix ) === 0 ) {
 638                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
 639                                         $endArray[] = $table;
 640                                 }
 641
 642                         }
 643                 }
 644
 645                 return $endArray;
 646         }
 647
 648 } // end DatabaseSqlite class
 649
 650 /**
 651  * This class allows simple acccess to a SQLite database independently from main database settings
 652  * @ingroup Database
 653  */
 654 class DatabaseSqliteStandalone extends DatabaseSqlite {
 655         public function __construct( $fileName, $flags = 0 ) {
 656                 $this->mFlags = $flags;
 657                 $this->tablePrefix( null );
 658                 $this->openFile( $fileName );
 659         }
 660 }
 661
 662 /**
 663  * @ingroup Database
 664  */
 665 class SQLiteField implements Field {
 666         private $info, $tableName;
 667         function __construct( $info, $tableName ) {
 668                 $this->info = $info;
 669                 $this->tableName = $tableName;
 670         }
 671
 672         function name() {
 673                 return $this->info->name;
 674         }
 675
 676         function tableName() {
 677                 return $this->tableName;
 678         }
 679
 680         function defaultValue() {
 681                 if ( is_string( $this->info->dflt_value ) ) {
 682                         // Typically quoted
 683                         if ( preg_match( '/^\'(.*)\'$', $this->info->dflt_value ) ) {
 684                                 return str_replace( "''", "'", $this->info->dflt_value );
 685                         }
 686                 }
 687                 return $this->info->dflt_value;
 688         }
 689
 690         function isNullable() {
 691                 return !$this->info->notnull;
 692         }
 693
 694         function type() {
 695                 return $this->info->type;
 696         }
 697
 698 } // end SQLiteField