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, $failFunction = false, $flags = 0 ) {
  27                 global $wgSharedDB;
  28                 $this->mFailFunction = $failFunction;
  29                 $this->mFlags = $flags;
  30                 $this->mName = $dbName;
  31
  32                 if ( $this->open( $server, $user, $password, $dbName ) && $wgSharedDB ) {
  33                         $this->attachDatabase( $wgSharedDB );
  34                 }
  35         }
  36
  37         /**
  38          * Serialization handler, see http://php.net/manual/en/language.oop5.magic.php#language.oop5.magic.sleep
  39          * for details. Instances of this class sometimes get serialized, e.g. with Title and its BacklinkCache
  40          * Because attempts to serialize mConn end in "can't serialize PDO objects" exceptions, we simply disallow
  41          * to serialize anything in this class.
  42          */
  43         function __sleep() {
  44                 return array();
  45         }
  46
  47         function getType() {
  48                 return 'sqlite';
  49         }
  50
  51         /**
  52          * @todo: check if it should be true like parent class
  53          */
  54         function implicitGroupby()   { return false; }
  55
  56         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 ) {
  57                 return new DatabaseSqlite( $server, $user, $password, $dbName, $failFunction, $flags );
  58         }
  59
  60         /** Open an SQLite database and return a resource handle to it
  61          *  NOTE: only $dbName is used, the other parameters are irrelevant for SQLite databases
  62          */
  63         function open( $server, $user, $pass, $dbName ) {
  64                 global $wgSQLiteDataDir;
  65
  66                 $fileName = self::generateFileName( $wgSQLiteDataDir, $dbName );
  67                 if ( !is_readable( $fileName ) ) {
  68                         $this->mConn = false;
  69                         throw new DBConnectionError( $this, "SQLite database not accessible" );
  70                 }
  71                 $this->openFile( $fileName );
  72                 return $this->mConn;
  73         }
  74
  75         /**
  76          * Opens a database file
  77          * @return SQL connection or false if failed
  78          */
  79         function openFile( $fileName ) {
  80                 $this->mDatabaseFile = $fileName;
  81                 try {
  82                         if ( $this->mFlags & DBO_PERSISTENT ) {
  83                                 $this->mConn = new PDO( "sqlite:$fileName", '', '',
  84                                         array( PDO::ATTR_PERSISTENT => true ) );
  85                         } else {
  86                                 $this->mConn = new PDO( "sqlite:$fileName", '', '' );
  87                         }
  88                 } catch ( PDOException $e ) {
  89                         $err = $e->getMessage();
  90                 }
  91                 if ( $this->mConn === false ) {
  92                         wfDebug( "DB connection error: $err\n" );
  93                         if ( !$this->mFailFunction ) {
  94                                 throw new DBConnectionError( $this, $err );
  95                         } else {
  96                                 return false;
  97                         }
  98
  99                 }
 100                 $this->mOpened = !!$this->mConn;
 101                 # set error codes only, don't raise exceptions
 102                 if ( $this->mOpened ) {
 103                         $this->mConn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
 104                         return true;
 105                 }
 106         }
 107
 108         /**
 109          * Close an SQLite database
 110          */
 111         function close() {
 112                 $this->mOpened = false;
 113                 if ( is_object( $this->mConn ) ) {
 114                         if ( $this->trxLevel() ) $this->commit();
 115                         $this->mConn = null;
 116                 }
 117                 return true;
 118         }
 119
 120         /**
 121          * Generates a database file name. Explicitly public for installer.
 122          * @param $dir String: Directory where database resides
 123          * @param $dbName String: Database name
 124          * @return String
 125          */
 126         public static function generateFileName( $dir, $dbName ) {
 127                 return "$dir/$dbName.sqlite";
 128         }
 129
 130         /**
 131          * Check if the searchindext table is FTS enabled.
 132          * @returns false if not enabled.
 133          */
 134         function checkForEnabledSearch() {
 135                 if ( self::$fulltextEnabled === null ) {
 136                         self::$fulltextEnabled = false;
 137                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = 'searchindex'", __METHOD__ );
 138                         if ( $res ) {
 139                                 $row = $res->fetchRow();
 140                                 self::$fulltextEnabled = stristr($row['sql'], 'fts' ) !== false;
 141                         }
 142                 }
 143                 return self::$fulltextEnabled;
 144         }
 145
 146         /**
 147          * Returns version of currently supported SQLite fulltext search module or false if none present.
 148          * @return String
 149          */
 150         function getFulltextSearchModule() {
 151                 $table = 'dummy_search_test';
 152                 $this->query( "DROP TABLE IF EXISTS $table", __METHOD__ );
 153
 154                 if ( $this->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 155                         $this->query( "DROP TABLE IF EXISTS $table", __METHOD__ );
 156                         return 'FTS3';
 157                 }
 158                 return false;
 159         }
 160
 161         /**
 162          * Attaches external database to our connection, see http://sqlite.org/lang_attach.html
 163          * for details.
 164          * @param $name String: database name to be used in queries like SELECT foo FROM dbname.table
 165          * @param $file String: database file name. If omitted, will be generated using $name and $wgSQLiteDataDir
 166          * @param $fname String: calling function name
 167          */
 168         function attachDatabase( $name, $file = false, $fname = 'DatabaseSqlite::attachDatabase' ) {
 169                 global $wgSQLiteDataDir;
 170                 if ( !$file ) {
 171                         $file = self::generateFileName( $wgSQLiteDataDir, $name );
 172                 }
 173                 $file = $this->addQuotes( $file );
 174                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 175         }
 176
 177         /**
 178          * @see DatabaseBase::isWriteQuery()
 179          */
 180         function isWriteQuery( $sql ) {
 181                 return parent::isWriteQuery( $sql ) && !preg_match( '/^ATTACH\b/i', $sql );
 182         }
 183
 184         /**
 185          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 186          */
 187         function doQuery( $sql ) {
 188                 $res = $this->mConn->query( $sql );
 189                 if ( $res === false ) {
 190                         return false;
 191                 } else {
 192                         $r = $res instanceof ResultWrapper ? $res->result : $res;
 193                         $this->mAffectedRows = $r->rowCount();
 194                         $res = new ResultWrapper( $this, $r->fetchAll() );
 195                 }
 196                 return $res;
 197         }
 198
 199         function freeResult( $res ) {
 200                 if ( $res instanceof ResultWrapper ) {
 201                         $res->result = null;
 202                 } else {
 203                         $res = null;
 204                 }
 205         }
 206
 207         function fetchObject( $res ) {
 208                 if ( $res instanceof ResultWrapper ) {
 209                         $r =& $res->result;
 210                 } else {
 211                         $r =& $res;
 212                 }
 213
 214                 $cur = current( $r );
 215                 if ( is_array( $cur ) ) {
 216                         next( $r );
 217                         $obj = new stdClass;
 218                         foreach ( $cur as $k => $v ) {
 219                                 if ( !is_numeric( $k ) ) {
 220                                         $obj->$k = $v;
 221                                 }
 222                         }
 223
 224                         return $obj;
 225                 }
 226                 return false;
 227         }
 228
 229         function fetchRow( $res ) {
 230                 if ( $res instanceof ResultWrapper ) {
 231                         $r =& $res->result;
 232                 } else {
 233                         $r =& $res;
 234                 }
 235                 $cur = current( $r );
 236                 if ( is_array( $cur ) ) {
 237                         next( $r );
 238                         return $cur;
 239                 }
 240                 return false;
 241         }
 242
 243         /**
 244          * The PDO::Statement class implements the array interface so count() will work
 245          */
 246         function numRows( $res ) {
 247                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 248                 return count( $r );
 249         }
 250
 251         function numFields( $res ) {
 252                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 253                 return is_array( $r ) ? count( $r[0] ) : 0;
 254         }
 255
 256         function fieldName( $res, $n ) {
 257                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 258                 if ( is_array( $r ) ) {
 259                         $keys = array_keys( $r[0] );
 260                         return $keys[$n];
 261                 }
 262                 return  false;
 263         }
 264
 265         /**
 266          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 267          */
 268         function tableName( $name ) {
 269                 // table names starting with sqlite_ are reserved
 270                 if ( strpos( $name, 'sqlite_' ) === 0 ) return $name;
 271                 return str_replace( '`', '', parent::tableName( $name ) );
 272         }
 273
 274         /**
 275          * Index names have DB scope
 276          */
 277         function indexName( $index ) {
 278                 return $index;
 279         }
 280
 281         /**
 282          * This must be called after nextSequenceVal
 283          */
 284         function insertId() {
 285                 return $this->mConn->lastInsertId();
 286         }
 287
 288         function dataSeek( $res, $row ) {
 289                 if ( $res instanceof ResultWrapper ) {
 290                         $r =& $res->result;
 291                 } else {
 292                         $r =& $res;
 293                 }
 294                 reset( $r );
 295                 if ( $row > 0 ) {
 296                         for ( $i = 0; $i < $row; $i++ ) {
 297                                 next( $r );
 298                         }
 299                 }
 300         }
 301
 302         function lastError() {
 303                 if ( !is_object( $this->mConn ) ) {
 304                         return "Cannot return last error, no db connection";
 305                 }
 306                 $e = $this->mConn->errorInfo();
 307                 return isset( $e[2] ) ? $e[2] : '';
 308         }
 309
 310         function lastErrno() {
 311                 if ( !is_object( $this->mConn ) ) {
 312                         return "Cannot return last error, no db connection";
 313                 } else {
 314                         $info = $this->mConn->errorInfo();
 315                         return $info[1];
 316                 }
 317         }
 318
 319         function affectedRows() {
 320                 return $this->mAffectedRows;
 321         }
 322
 323         /**
 324          * Returns information about an index
 325          * Returns false if the index does not exist
 326          * - if errors are explicitly ignored, returns NULL on failure
 327          */
 328         function indexInfo( $table, $index, $fname = 'DatabaseSqlite::indexExists' ) {
 329                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 330                 $res = $this->query( $sql, $fname );
 331                 if ( !$res ) {
 332                         return null;
 333                 }
 334                 if ( $res->numRows() == 0 ) {
 335                         return false;
 336                 }
 337                 $info = array();
 338                 foreach ( $res as $row ) {
 339                         $info[] = $row->name;
 340                 }
 341                 return $info;
 342         }
 343
 344         function indexUnique( $table, $index, $fname = 'DatabaseSqlite::indexUnique' ) {
 345                 $row = $this->selectRow( 'sqlite_master', '*',
 346                         array(
 347                                 'type' => 'index',
 348                                 'name' => $this->indexName( $index ),
 349                         ), $fname );
 350                 if ( !$row || !isset( $row->sql ) ) {
 351                         return null;
 352                 }
 353
 354                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 355                 $indexPos = strpos( $row->sql, 'INDEX' );
 356                 if ( $indexPos === false ) {
 357                         return null;
 358                 }
 359                 $firstPart = substr( $row->sql, 0, $indexPos );
 360                 $options = explode( ' ', $firstPart );
 361                 return in_array( 'UNIQUE', $options );
 362         }
 363
 364         /**
 365          * Filter the options used in SELECT statements
 366          */
 367         function makeSelectOptions( $options ) {
 368                 foreach ( $options as $k => $v ) {
 369                         if ( is_numeric( $k ) && $v == 'FOR UPDATE' ) {
 370                                 $options[$k] = '';
 371                         }
 372                 }
 373                 return parent::makeSelectOptions( $options );
 374         }
 375
 376         /**
 377          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 378          */
 379         function insert( $table, $a, $fname = 'DatabaseSqlite::insert', $options = array() ) {
 380                 if ( !count( $a ) ) {
 381                         return true;
 382                 }
 383                 if ( !is_array( $options ) ) {
 384                         $options = array( $options );
 385                 }
 386
 387                 # SQLite uses OR IGNORE not just IGNORE
 388                 foreach ( $options as $k => $v ) {
 389                         if ( $v == 'IGNORE' ) {
 390                                 $options[$k] = 'OR IGNORE';
 391                         }
 392                 }
 393
 394                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 395                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 396                         $ret = true;
 397                         foreach ( $a as $k => $v ) {
 398                                 if ( !parent::insert( $table, $v, "$fname/multi-row", $options ) ) {
 399                                         $ret = false;
 400                                 }
 401                         }
 402                 } else {
 403                         $ret = parent::insert( $table, $a, "$fname/single-row", $options );
 404                 }
 405
 406                 return $ret;
 407         }
 408
 409         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabaseSqlite::replace' ) {
 410                 if ( !count( $rows ) ) return true;
 411
 412                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 413                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 414                         $ret = true;
 415                         foreach ( $rows as $k => $v ) {
 416                                 if ( !parent::replace( $table, $uniqueIndexes, $v, "$fname/multi-row" ) ) {
 417                                         $ret = false;
 418                                 }
 419                         }
 420                 } else {
 421                         $ret = parent::replace( $table, $uniqueIndexes, $rows, "$fname/single-row" );
 422                 }
 423
 424                 return $ret;
 425         }
 426
 427         /**
 428          * Returns the size of a text field, or -1 for "unlimited"
 429          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 430          */
 431         function textFieldSize( $table, $field ) {
 432                 return - 1;
 433         }
 434
 435         function unionSupportsOrderAndLimit() {
 436                 return false;
 437         }
 438
 439         function unionQueries( $sqls, $all ) {
 440                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 441                 return implode( $glue, $sqls );
 442         }
 443
 444         function wasDeadlock() {
 445                 return $this->lastErrno() == 5; // SQLITE_BUSY
 446         }
 447
 448         function wasErrorReissuable() {
 449                 return $this->lastErrno() ==  17; // SQLITE_SCHEMA;
 450         }
 451
 452         function wasReadOnlyError() {
 453                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 454         }
 455
 456         /**
 457          * @return string wikitext of a link to the server software's web site
 458          */
 459         public static function getSoftwareLink() {
 460                 return "[http://sqlite.org/ SQLite]";
 461         }
 462
 463         /**
 464          * @return string Version information from the database
 465          */
 466         function getServerVersion() {
 467                 $ver = $this->mConn->getAttribute( PDO::ATTR_SERVER_VERSION );
 468                 return $ver;
 469         }
 470
 471         /**
 472          * Get information about a given field
 473          * Returns false if the field does not exist.
 474          */
 475         function fieldInfo( $table, $field ) {
 476                 $tableName = $this->tableName( $table );
 477                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 478                 $res = $this->query( $sql, __METHOD__ );
 479                 foreach ( $res as $row ) {
 480                         if ( $row->name == $field ) {
 481                                 return new SQLiteField( $row, $tableName );
 482                         }
 483                 }
 484                 return false;
 485         }
 486
 487         function begin( $fname = '' ) {
 488                 if ( $this->mTrxLevel == 1 ) $this->commit();
 489                 $this->mConn->beginTransaction();
 490                 $this->mTrxLevel = 1;
 491         }
 492
 493         function commit( $fname = '' ) {
 494                 if ( $this->mTrxLevel == 0 ) return;
 495                 $this->mConn->commit();
 496                 $this->mTrxLevel = 0;
 497         }
 498
 499         function rollback( $fname = '' ) {
 500                 if ( $this->mTrxLevel == 0 ) return;
 501                 $this->mConn->rollBack();
 502                 $this->mTrxLevel = 0;
 503         }
 504
 505         function limitResultForUpdate( $sql, $num ) {
 506                 return $this->limitResult( $sql, $num );
 507         }
 508
 509         function strencode( $s ) {
 510                 return substr( $this->addQuotes( $s ), 1, - 1 );
 511         }
 512
 513         function encodeBlob( $b ) {
 514                 return new Blob( $b );
 515         }
 516
 517         function decodeBlob( $b ) {
 518                 if ( $b instanceof Blob ) {
 519                         $b = $b->fetch();
 520                 }
 521                 return $b;
 522         }
 523
 524         function addQuotes( $s ) {
 525                 if ( $s instanceof Blob ) {
 526                         return "x'" . bin2hex( $s->fetch() ) . "'";
 527                 } else {
 528                         return $this->mConn->quote( $s );
 529                 }
 530         }
 531
 532         function quote_ident( $s ) {
 533                 return $s;
 534         }
 535
 536         function buildLike() {
 537                 $params = func_get_args();
 538                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
 539                         $params = $params[0];
 540                 }
 541                 return parent::buildLike( $params ) . "ESCAPE '\' ";
 542         }
 543
 544         /**
 545          * Called by the installer script (when modified according to the MediaWikiLite installation instructions)
 546          * - this is the same way PostgreSQL works, MySQL reads in tables.sql and interwiki.sql using dbsource (which calls db->sourceFile)
 547          */
 548         public function setup_database() {
 549                 global $IP;
 550
 551                 # Process common MySQL/SQLite table definitions
 552                 $err = $this->sourceFile( "$IP/maintenance/tables.sql" );
 553                 if ( $err !== true ) {
 554                         echo " <b>FAILED</b></li>";
 555                         dieout( htmlspecialchars( $err ) );
 556                 }
 557                 echo " done.</li>";
 558
 559                 # Use DatabasePostgres's code to populate interwiki from MySQL template
 560                 $f = fopen( "$IP/maintenance/interwiki.sql", 'r' );
 561                 if ( !$f ) {
 562                         dieout( "Could not find the interwiki.sql file." );
 563                 }
 564
 565                 $sql = "INSERT INTO interwiki(iw_prefix,iw_url,iw_local,iw_api,iw_wikiid) VALUES ";
 566                 while ( !feof( $f ) ) {
 567                         $line = fgets( $f, 1024 );
 568                         $matches = array();
 569                         if ( !preg_match( '/^\s*(\(.+?),(\d)\)/', $line, $matches ) ) continue;
 570                         $this->query( "$sql $matches[1],$matches[2],'','')" );
 571                 }
 572         }
 573
 574         public function getSearchEngine() {
 575                 return "SearchSqlite";
 576         }
 577
 578         /**
 579          * No-op version of deadlockLoop
 580          */
 581         public function deadlockLoop( /*...*/ ) {
 582                 $args = func_get_args();
 583                 $function = array_shift( $args );
 584                 return call_user_func_array( $function, $args );
 585         }
 586
 587         protected function replaceVars( $s ) {
 588                 $s = parent::replaceVars( $s );
 589                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 590                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 591
 592                         // binary/varbinary column type -> blob
 593                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 594                         // no such thing as unsigned
 595                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 596                         // INT -> INTEGER
 597                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\([\s\d]*\)|\b)/i', 'INTEGER', $s );
 598                         // varchar -> TEXT
 599                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 600                         // TEXT normalization
 601                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 602                         // BLOB normalization
 603                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 604                         // BOOL -> INTEGER
 605                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 606                         // DATETIME -> TEXT
 607                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 608                         // No ENUM type
 609                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 610                         // binary collation type -> nothing
 611                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 612                         // auto_increment -> autoincrement
 613                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 614                         // No explicit options
 615                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 616                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 617                         // No truncated indexes
 618                         $s = preg_replace( '/\(\d+\)/', '', $s );
 619                         // No FULLTEXT
 620                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 621                 }
 622                 return $s;
 623         }
 624
 625         /*
 626          * Build a concatenation list to feed into a SQL query
 627          */
 628         function buildConcat( $stringList ) {
 629                 return '(' . implode( ') || (', $stringList ) . ')';
 630         }
 631
 632         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabaseSqlite::duplicateTableStructure' ) {
 633                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name='$oldName' AND type='table'", $fname );
 634                 $obj = $this->fetchObject( $res );
 635                 if ( !$obj ) {
 636                         throw new MWException( "Couldn't retrieve structure for table $oldName" );
 637                 }
 638                 $sql = $obj->sql;
 639                 $sql = preg_replace( '/\b' . preg_quote( $oldName ) . '\b/', $newName, $sql, 1 );
 640                 return $this->query( $sql, $fname );
 641         }
 642
 643 } // end DatabaseSqlite class
 644
 645 /**
 646  * This class allows simple acccess to a SQLite database independently from main database settings
 647  * @ingroup Database
 648  */
 649 class DatabaseSqliteStandalone extends DatabaseSqlite {
 650         public function __construct( $fileName, $flags = 0 ) {
 651                 $this->mFlags = $flags;
 652                 $this->tablePrefix( null );
 653                 $this->openFile( $fileName );
 654         }
 655 }
 656
 657 /**
 658  * @ingroup Database
 659  */
 660 class SQLiteField {
 661         private $info, $tableName;
 662         function __construct( $info, $tableName ) {
 663                 $this->info = $info;
 664                 $this->tableName = $tableName;
 665         }
 666
 667         function name() {
 668                 return $this->info->name;
 669         }
 670
 671         function tableName() {
 672                 return $this->tableName;
 673         }
 674
 675         function defaultValue() {
 676                 if ( is_string( $this->info->dflt_value ) ) {
 677                         // Typically quoted
 678                         if ( preg_match( '/^\'(.*)\'$', $this->info->dflt_value ) ) {
 679                                 return str_replace( "''", "'", $this->info->dflt_value );
 680                         }
 681                 }
 682                 return $this->info->dflt_value;
 683         }
 684
 685         function maxLength() {
 686                 return -1;
 687         }
 688
 689         function nullable() {
 690                 // SQLite dynamic types are always nullable
 691                 return true;
 692         }
 693
 694         # isKey(),  isMultipleKey() not implemented, MySQL-specific concept.
 695         # Suggest removal from base class [TS]
 696
 697         function type() {
 698                 return $this->info->type;
 699         }
 700
 701 } // end SQLiteField