<?php
// vim: set et ts=4 sw=4 fdm=marker:
// +----------------------------------------------------------------------+
// | PHP versions 4 and 5                                                 |
// +----------------------------------------------------------------------+
// | Copyright (c) 1998-2007 Manuel Lemos, Tomas V.V.Cox,                 |
// | Stig. S. Bakken, Lukas Smith                                         |
// | All rights reserved.                                                 |
// +----------------------------------------------------------------------+
// | MDB2 is a merge of PEAR DB and Metabases that provides a unified DB  |
// | API as well as database abstraction for PHP applications.            |
// | This LICENSE is in the BSD license style.                            |
// |                                                                      |
// | Redistribution and use in source and binary forms, with or without   |
// | modification, are permitted provided that the following conditions   |
// | are met:                                                             |
// |                                                                      |
// | Redistributions of source code must retain the above copyright       |
// | notice, this list of conditions and the following disclaimer.        |
// |                                                                      |
// | Redistributions in binary form must reproduce the above copyright    |
// | notice, this list of conditions and the following disclaimer in the  |
// | documentation and/or other materials provided with the distribution. |
// |                                                                      |
// | Neither the name of Manuel Lemos, Tomas V.V.Cox, Stig. S. Bakken,    |
// | Lukas Smith nor the names of his contributors may be used to endorse |
// | or promote products derived from this software without specific prior|
// | written permission.                                                  |
// |                                                                      |
// | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS  |
// | "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT    |
// | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS    |
// | FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE      |
// | REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,          |
// | INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
// | BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS|
// |  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED  |
// | AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT          |
// | LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY|
// | WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE          |
// | POSSIBILITY OF SUCH DAMAGE.                                          |
// +----------------------------------------------------------------------+
// | Author: Lukas Smith <smith@pooteeweet.org>                           |
// +----------------------------------------------------------------------+
//
// $Id$
//

/**
 * MDB2 SQLite driver
 *
 * @package MDB2
 * @category Database
 * @author  Lukas Smith <smith@pooteeweet.org>
 */
class MDB2_Driver_sqlite extends MDB2_Driver_Common
{
    // {{{ properties
    var $string_quoting = array('start' => "'", 'end' => "'", 'escape' => "'", 'escape_pattern' => false);

    var $identifier_quoting = array('start' => '"', 'end' => '"', 'escape' => '"');

    var $_lasterror = '';

    var $fix_assoc_fields_names = false;

    // }}}
    // {{{ constructor

    /**
     * Constructor
     */
    function __construct()
    {
        parent::__construct();

        $this->phptype = 'sqlite';
        $this->dbsyntax = 'sqlite';

        $this->supported['sequences'] = 'emulated';
        $this->supported['indexes'] = true;
        $this->supported['affected_rows'] = true;
        $this->supported['summary_functions'] = true;
        $this->supported['order_by_text'] = true;
        $this->supported['current_id'] = 'emulated';
        $this->supported['limit_queries'] = true;
        $this->supported['LOBs'] = true;
        $this->supported['replace'] = true;
        $this->supported['transactions'] = true;
        $this->supported['savepoints'] = false;
        $this->supported['sub_selects'] = true;
        $this->supported['auto_increment'] = true;
        $this->supported['primary_key'] = false; // requires alter table implementation
        $this->supported['result_introspection'] = false; // not implemented
        $this->supported['prepared_statements'] = 'emulated';
        $this->supported['identifier_quoting'] = true;
        $this->supported['pattern_escaping'] = false;
        $this->supported['new_link'] = false;

        $this->options['base_transaction_name'] = '___php_MDB2_sqlite_auto_commit_off';
        $this->options['fixed_float'] = 0;
        $this->options['database_path'] = '';
        $this->options['database_extension'] = '';
        $this->options['server_version'] = '';
    }

    // }}}
    // {{{ errorInfo()

    /**
     * This method is used to collect information about an error
     *
     * @param integer $error
     * @return array
     * @access public
     */
    function errorInfo($error = null)
    {
        $native_code = null;
        if ($this->connection) {
            $native_code = @sqlite_last_error($this->connection);
        }
        $native_msg = $this->_lasterror
            ? html_entity_decode($this->_lasterror) : @sqlite_error_string($native_code);
            
        // PHP 5.2+ prepends the function name to $php_errormsg, so we need
        // this hack to work around it, per bug #9599.
        $native_msg = preg_replace('/^sqlite[a-z_]+\(\): /', '', $native_msg);

        if (is_null($error)) {
            static $error_regexps;
            if (empty($error_regexps)) {
                $error_regexps = array(
                    '/^no such table:/' => MDB2_ERROR_NOSUCHTABLE,
                    '/^no such index:/' => MDB2_ERROR_NOT_FOUND,
                    '/^(table|index) .* already exists$/' => MDB2_ERROR_ALREADY_EXISTS,
                    '/PRIMARY KEY must be unique/i' => MDB2_ERROR_CONSTRAINT,
                    '/is not unique/' => MDB2_ERROR_CONSTRAINT,
                    '/columns .* are not unique/i' => MDB2_ERROR_CONSTRAINT,
                    '/uniqueness constraint failed/' => MDB2_ERROR_CONSTRAINT,
                    '/may not be NULL/' => MDB2_ERROR_CONSTRAINT_NOT_NULL,
                    '/^no such column:/' => MDB2_ERROR_NOSUCHFIELD,
                    '/column not present in both tables/i' => MDB2_ERROR_NOSUCHFIELD,
                    '/^near ".*": syntax error$/' => MDB2_ERROR_SYNTAX,
                    '/[0-9]+ values for [0-9]+ columns/i' => MDB2_ERROR_VALUE_COUNT_ON_ROW,
                 );
            }
            foreach ($error_regexps as $regexp => $code) {
                if (preg_match($regexp, $native_msg)) {
                    $error = $code;
                    break;
                }
            }
        }
        return array($error, $native_code, $native_msg);
    }

    // }}}
    // {{{ escape()

    /**
     * Quotes a string so it can be safely used in a query. It will quote
     * the text so it can safely be used within a query.
     *
     * @param   string  the input string to quote
     * @param   bool    escape wildcards
     *
     * @return  string  quoted string
     *
     * @access  public
     */
    function escape($text, $escape_wildcards = false)
    {
        $text = @sqlite_escape_string($text);
        return $text;
    }

    // }}}
    // {{{ beginTransaction()

    /**
     * Start a transaction or set a savepoint.
     *
     * @param   string  name of a savepoint to set
     * @return  mixed   MDB2_OK on success, a MDB2 error on failure
     *
     * @access  public
     */
    function beginTransaction($savepoint = null)
    {
        $this->debug('Starting transaction/savepoint', __FUNCTION__, array('is_manip' => true, 'savepoint' => $savepoint));
        if (!is_null($savepoint)) {
            return $this->raiseError(MDB2_ERROR_UNSUPPORTED, null, null,
                'savepoints are not supported', __FUNCTION__);
        } elseif ($this->in_transaction) {
            return MDB2_OK;  //nothing to do
        }
        if (!$this->destructor_registered && $this->opened_persistent) {
            $this->destructor_registered = true;
            register_shutdown_function('MDB2_closeOpenTransactions');
        }
        $query = 'BEGIN TRANSACTION '.$this->options['base_transaction_name'];
        $result =& $this->_doQuery($query, true);
        if (PEAR::isError($result)) {
            return $result;
        }
        $this->in_transaction = true;
        return MDB2_OK;
    }

    // }}}
    // {{{ commit()

    /**
     * Commit the database changes done during a transaction that is in
     * progress or release a savepoint. This function may only be called when
     * auto-committing is disabled, otherwise it will fail. Therefore, a new
     * transaction is implicitly started after committing the pending changes.
     *
     * @param   string  name of a savepoint to release
     * @return  mixed   MDB2_OK on success, a MDB2 error on failure
     *
     * @access  public
     */
    function commit($savepoint = null)
    {
        $this->debug('Committing transaction/savepoint', __FUNCTION__, array('is_manip' => true, 'savepoint' => $savepoint));
        if (!$this->in_transaction) {
            return $this->raiseError(MDB2_ERROR_INVALID, null, null,
                'commit/release savepoint cannot be done changes are auto committed', __FUNCTION__);
        }
        if (!is_null($savepoint)) {
            return $this->raiseError(MDB2_ERROR_UNSUPPORTED, null, null,
                'savepoints are not supported', __FUNCTION__);
        }

        $query = 'COMMIT TRANSACTION '.$this->options['base_transaction_name'];
        $result =& $this->_doQuery($query, true);
        if (PEAR::isError($result)) {
            return $result;
        }
        $this->in_transaction = false;
        return MDB2_OK;
    }

    // }}}
    // {{{

    /**
     * Cancel any database changes done during a transaction or since a specific
     * savepoint that is in progress. This function may only be called when
     * auto-committing is disabled, otherwise it will fail. Therefore, a new
     * transaction is implicitly started after canceling the pending changes.
     *
     * @param   string  name of a savepoint to rollback to
     * @return  mixed   MDB2_OK on success, a MDB2 error on failure
     *
     * @access  public
     */
    function rollback($savepoint = null)
    {
        $this->debug('Rolling back transaction/savepoint', __FUNCTION__, array('is_manip' => true, 'savepoint' => $savepoint));
        if (!$this->in_transaction) {
            return $this->raiseError(MDB2_ERROR_INVALID, null, null,
                'rollback cannot be done changes are auto committed', __FUNCTION__);
        }
        if (!is_null($savepoint)) {
            return $this->raiseError(MDB2_ERROR_UNSUPPORTED, null, null,
                'savepoints are not supported', __FUNCTION__);
        }

        $query = 'ROLLBACK TRANSACTION '.$this->options['base_transaction_name'];
        $result =& $this->_doQuery($query, true);
        if (PEAR::isError($result)) {
            return $result;
        }
        $this->in_transaction = false;
        return MDB2_OK;
    }

    // }}}
    // {{{ function setTransactionIsolation()

    /**
     * Set the transacton isolation level.
     *
     * @param   string  standard isolation level
     *                  READ UNCOMMITTED (allows dirty reads)
     *                  READ COMMITTED (prevents dirty reads)
     *                  REPEATABLE READ (prevents nonrepeatable reads)
     *                  SERIALIZABLE (prevents phantom reads)
     * @return  mixed   MDB2_OK on success, a MDB2 error on failure
     *
     * @access  public
     * @since   2.1.1
     */
    function setTransactionIsolation($isolation)
    {
        $this->debug('Setting transaction isolation level', __FUNCTION__, array('is_manip' => true));
        switch ($isolation) {
        case 'READ UNCOMMITTED':
            $isolation = 0;
            break;
        case 'READ COMMITTED':
        case 'REPEATABLE READ':
        case 'SERIALIZABLE':
            $isolation = 1;
            break;
        default:
            return $this->raiseError(MDB2_ERROR_UNSUPPORTED, null, null,
                'isolation level is not supported: '.$isolation, __FUNCTION__);
        }

        $query = "PRAGMA read_uncommitted=$isolation";
        return $this->_doQuery($query, true);
    }

    // }}}
    // {{{ getDatabaseFile()

    /**
     * Builds the string with path+dbname+extension
     *
     * @return string full database path+file
     * @access protected
     */
    function _getDatabaseFile($database_name)
    {
        if ($database_name === '' || $database_name === ':memory:') {
            return $database_name;
        }
        return $this->options['database_path'].$database_name.$this->options['database_extension'];
    }

    // }}}
    // {{{ connect()

    /**
     * Connect to the database
     *
     * @return true on success, MDB2 Error Object on failure
     **/
    function connect()
    {
        $database_file = $this->_getDatabaseFile($this->database_name);
        if (is_resource($this->connection)) {
            if (count(array_diff($this->connected_dsn, $this->dsn)) == 0
                && $this->connected_database_name == $database_file
                && $this->opened_persistent == $this->options['persistent']
            ) {
                return MDB2_OK;
            }
            $this->disconnect(false);
        }

        if (!PEAR::loadExtension($this->phptype)) {
            return $this->raiseError(MDB2_ERROR_NOT_FOUND, null, null,
                'extension '.$this->phptype.' is not compiled into PHP', __FUNCTION__);
        }

        if (!empty($this->database_name)) {
            if ($database_file !== ':memory:') {
                if (!file_exists($database_file)) {
                    if (!touch($database_file)) {
                        return $this->raiseError(MDB2_ERROR_NOT_FOUND, null, null,
                            'Could not create database file', __FUNCTION__);
                    }
                    if (!isset($this->dsn['mode'])
                        || !is_numeric($this->dsn['mode'])
                    ) {
                        $mode = 0644;
                    } else {
                        $mode = octdec($this->dsn['mode']);
                    }
                    if (!chmod($database_file, $mode)) {
                        return $this->raiseError(MDB2_ERROR_NOT_FOUND, null, null,
                            'Could not be chmodded database file', __FUNCTION__);
                    }
                    if (!file_exists($database_file)) {
                        return $this->raiseError(MDB2_ERROR_NOT_FOUND, null, null,
                            'Could not be found database file', __FUNCTION__);
                    }
                }
                if (!is_file($database_file)) {
                    return $this->raiseError(MDB2_ERROR_INVALID, null, null,
                            'Database is a directory name', __FUNCTION__);
                }
                if (!is_readable($database_file)) {
                    return $this->raiseError(MDB2_ERROR_ACCESS_VIOLATION, null, null,
                            'Could not read database file', __FUNCTION__);
                }
            }

            $connect_function = ($this->options['persistent'] ? 'sqlite_popen' : 'sqlite_open');
            $php_errormsg = '';
            if (version_compare('5.1.0', PHP_VERSION, '>')) {
                @ini_set('track_errors', true);
                $connection = @$connect_function($database_file);
                @ini_restore('track_errors');
            } else {
                $connection = @$connect_function($database_file, 0666, $php_errormsg);
            }
            $this->_lasterror = $php_errormsg;
            if (!$connection) {
                return $this->raiseError(MDB2_ERROR_CONNECT_FAILED, null, null,
                'unable to establish a connection', __FUNCTION__);
            }

            if (!empty($this->dsn['charset'])) {
                $result = $this->setCharset($this->dsn['charset'], $connection);
                if (PEAR::isError($result)) {
                    return $result;
                }
            }

            $this->connection = $connection;
            $this->connected_dsn = $this->dsn;
            $this->connected_database_name = $database_file;
            $this->opened_persistent = $this->getoption('persistent');
            $this->dbsyntax = $this->dsn['dbsyntax'] ? $this->dsn['dbsyntax'] : $this->phptype;
        }
        return MDB2_OK;
    }

    // }}}
    // {{{ disconnect()

    /**
     * Log out and disconnect from the database.
     *
     * @param  boolean $force if the disconnect should be forced even if the
     *                        connection is opened persistently
     * @return mixed true on success, false if not connected and error
     *                object on error
     * @access public
     */
    function disconnect($force = true)
    {
        if (is_resource($this->connection)) {
            if ($this->in_transaction) {
                $dsn = $this->dsn;
                $database_name = $this->database_name;
                $persistent = $this->options['persistent'];
                $this->dsn = $this->connected_dsn;
                $this->database_name = $this->connected_database_name;
                $this->options['persistent'] = $this->opened_persistent;
                $this->rollback();
                $this->dsn = $dsn;
                $this->database_name = $database_name;
                $this->options['persistent'] = $persistent;
            }

            if (!$this->opened_persistent || $force) {
                @sqlite_close($this->connection);
            }
        }
        return parent::disconnect($force);
    }

    // }}}
    // {{{ getConnection()

    /**
     * Returns a native connection
     *
     * @return  mixed   a valid MDB2 connection object,
     *                  or a MDB2 error object on error
     * @access  public
     */
    function getConnection()
    {
        $connection = parent::getConnection();
        if (PEAR::isError($connection)) {
            return $connection;
        }

        $fix_assoc_fields_names = $this->options['portability'] & MDB2_PORTABILITY_FIX_ASSOC_FIELD_NAMES;
        if ($fix_assoc_fields_names !== $this->fix_assoc_fields_names) {
            @sqlite_query("PRAGMA short_column_names = $fix_assoc_fields_names;", $connection);
            $this->fix_assoc_fields_names = $fix_assoc_fields_names;
        }

        return $connection;
    }

    // }}}
    // {{{ _doQuery()

    /**
     * Execute a query
     * @param string $query  query
     * @param boolean $is_manip  if the query is a manipulation query
     * @param resource $connection
     * @param string $database_name
     * @return result or error object
     * @access protected
     */
    function &_doQuery($query, $is_manip = false, $connection = null, $database_name = null)
    {
        $this->last_query = $query;
        $result = $this->debug($query, 'query', array('is_manip' => $is_manip, 'when' => 'pre'));
        if ($result) {
            if (PEAR::isError($result)) {
                return $result;
            }
            $query = $result;
        }
        if ($this->options['disable_query']) {
            $result = $is_manip ? 0 : null;
            return $result;
        }

        if (is_null($connection)) {
            $connection = $this->getConnection();
            if (PEAR::isError($connection)) {
                return $connection;
            }
        }

        $function = $this->options['result_buffering']
            ? 'sqlite_query' : 'sqlite_unbuffered_query';
        $php_errormsg = '';
        if (version_compare('5.1.0', PHP_VERSION, '>')) {
            @ini_set('track_errors', true);
            do {
                $result = @$function($query.';', $connection);
            } while (sqlite_last_error($connection) == SQLITE_SCHEMA);
            @ini_restore('track_errors');
        } else {
            do {
                $result = @$function($query.';', $connection, SQLITE_BOTH, $php_errormsg);
            } while (sqlite_last_error($connection) == SQLITE_SCHEMA);
        }
        $this->_lasterror = $php_errormsg;

        if (!$result) {
            $err =& $this->raiseError(null, null, null,
                'Could not execute statement', __FUNCTION__);
            return $err;
        }

        $this->debug($query, 'query', array('is_manip' => $is_manip, 'when' => 'post', 'result' => $result));
        return $result;
    }

    // }}}
    // {{{ _affectedRows()

    /**
     * Returns the number of rows affected
     *
     * @param resource $result
     * @param resource $connection
     * @return mixed MDB2 Error Object or the number of rows affected
     * @access private
     */
    function _affectedRows($connection, $result = null)
    {
        if (is_null($connection)) {
            $connection = $this->getConnection();
            if (PEAR::isError($connection)) {
                return $connection;
            }
        }
        return @sqlite_changes($connection);
    }

    // }}}
    // {{{ _modifyQuery()

    /**
     * Changes a query string for various DBMS specific reasons
     *
     * @param string $query  query to modify
     * @param boolean $is_manip  if it is a DML query
     * @param integer $limit  limit the number of rows
     * @param integer $offset  start reading from given offset
     * @return string modified query
     * @access protected
     */
    function _modifyQuery($query, $is_manip, $limit, $offset)
    {
        if ($this->options['portability'] & MDB2_PORTABILITY_DELETE_COUNT) {
            if (preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $query)) {
                $query = preg_replace('/^\s*DELETE\s+FROM\s+(\S+)\s*$/',
                                      'DELETE FROM \1 WHERE 1=1', $query);
            }
        }
        if ($limit > 0
            && !preg_match('/LIMIT\s*\d(\s*(,|OFFSET)\s*\d+)?/i', $query)
        ) {
            $query = rtrim($query);
            if (substr($query, -1) == ';') {
                $query = substr($query, 0, -1);
            }
            if ($is_manip) {
                $query.= " LIMIT $limit";
            } else {
                $query.= " LIMIT $offset,$limit";
            }
        }
        return $query;
    }

    // }}}
    // {{{ getServerVersion()

    /**
     * return version information about the server
     *
     * @param bool   $native  determines if the raw version string should be returned
     * @return mixed array/string with version information or MDB2 error object
     * @access public
     */
    function getServerVersion($native = false)
    {
        $server_info = false;
        if ($this->connected_server_info) {
            $server_info = $this->connected_server_info;
        } elseif ($this->options['server_version']) {
            $server_info = $this->options['server_version'];
        } elseif (function_exists('sqlite_libversion')) {
            $server_info = @sqlite_libversion();
        }
        if (!$server_info) {
            return $this->raiseError(MDB2_ERROR_UNSUPPORTED, null, null,
                'Requires either the "server_version" option or the sqlite_libversion() function', __FUNCTION__);
        }
        // cache server_info
        $this->connected_server_info = $server_info;
        if (!$native) {
            $tmp = explode('.', $server_info, 3);
            $server_info = array(
                'major' => isset($tmp[0]) ? $tmp[0] : null,
                'minor' => isset($tmp[1]) ? $tmp[1] : null,
                'patch' => isset($tmp[2]) ? $tmp[2] : null,
                'extra' => null,
                'native' => $server_info,
            );
        }
        return $server_info;
    }

    // }}}
    // {{{ replace()

    /**
     * Execute a SQL REPLACE query. A REPLACE query is identical to a INSERT
     * query, except that if there is already a row in the table with the same
     * key field values, the REPLACE query just updates its values instead of
     * inserting a new row.
     *
     * The REPLACE type of query does not make part of the SQL standards. Since
     * practically only SQLite implements it natively, this type of query is
     * emulated through this method for other DBMS using standard types of
     * queries inside a transaction to assure the atomicity of the operation.
     *
     * @access public
     *
     * @param string $table name of the table on which the REPLACE query will
     *  be executed.
     * @param array $fields associative array that describes the fields and the
     *  values that will be inserted or updated in the specified table. The
     *  indexes of the array are the names of all the fields of the table. The
     *  values of the array are also associative arrays that describe the
     *  values and other properties of the table fields.
     *
     *  Here follows a list of field properties that need to be specified:
     *
     *    value:
     *          Value to be assigned to the specified field. This value may be
     *          of specified in database independent type format as this
     *          function can perform the necessary datatype conversions.
     *
     *    Default:
     *          this property is required unless the Null property
     *          is set to 1.
     *
     *    type
     *          Name of the type of the field. Currently, all types Metabase
     *          are supported except for clob and blob.
     *
     *    Default: no type conversion
     *
     *    null
     *          Boolean property that indicates that the value for this field
     *          should be set to null.
     *
     *          The default value for fields missing in INSERT queries may be
     *          specified the definition of a table. Often, the default value
     *          is already null, but since the REPLACE may be emulated using
     *          an UPDATE query, make sure that all fields of the table are
     *          listed in this function argument array.
     *
     *    Default: 0
     *
     *    key
     *          Boolean property that indicates that this field should be
     *          handled as a primary key or at least as part of the compound
     *          unique index of the table that will determine the row that will
     *          updated if it exists or inserted a new row otherwise.
     *
     *          This function will fail if no key field is specified or if the
     *          value of a key field is set to null because fields that are
     *          part of unique index they may not be null.
     *
     *    Default: 0
     *
     * @return mixed MDB2_OK on success, a MDB2 error on failure
     */
    function replace($table, $fields)
    {
        $count = count($fields);
        $query = $values = '';
        $keys = $colnum = 0;
        for (reset($fields); $colnum < $count; next($fields), $colnum++) {
            $name = key($fields);
            if ($colnum > 0) {
                $query .= ',';
                $values.= ',';
            }
            $query.= $name;
            if (isset($fields[$name]['null']) && $fields[$name]['null']) {
                $value = 'NULL';
            } else {
                $type = isset($fields[$name]['type']) ? $fields[$name]['type'] : null;
                $value = $this->quote($fields[$name]['value'], $type);
            }
            $values.= $value;
            if (isset($fields[$name]['key']) && $fields[$name]['key']) {
                if ($value === 'NULL') {
                    return $this->raiseError(MDB2_ERROR_CANNOT_REPLACE, null, null,
                        'key value '.$name.' may not be NULL', __FUNCTION__);
                }
                $keys++;
            }
        }
        if ($keys == 0) {
            return $this->raiseError(MDB2_ERROR_CANNOT_REPLACE, null, null,
                'not specified which fields are keys', __FUNCTION__);
        }

        $connection = $this->getConnection();
        if (PEAR::isError($connection)) {
            return $connection;
        }

        $query = "REPLACE INTO $table ($query) VALUES ($values)";
        $result =& $this->_doQuery($query, true, $connection);
        if (PEAR::isError($result)) {
            return $result;
        }
        return $this->_affectedRows($connection, $result);
    }

    // }}}
    // {{{ nextID()

    /**
     * Returns the next free id of a sequence
     *
     * @param string $seq_name name of the sequence
     * @param boolean $ondemand when true the sequence is
     *                          automatic created, if it
     *                          not exists
     *
     * @return mixed MDB2 Error Object or id
     * @access public
     */
    function nextID($seq_name, $ondemand = true)
    {
        $sequence_name = $this->quoteIdentifier($this->getSequenceName($seq_name), true);
        $seqcol_name = $this->options['seqcol_name'];
        $query = "INSERT INTO $sequence_name ($seqcol_name) VALUES (NULL)";
        $this->expectError(MDB2_ERROR_NOSUCHTABLE);
        $result =& $this->_doQuery($query, true);
        $this->popExpect();
        if (PEAR::isError($result)) {
            if ($ondemand && $result->getCode() == MDB2_ERROR_NOSUCHTABLE) {
                $this->loadModule('Manager', null, true);
                $result = $this->manager->createSequence($seq_name);
                if (PEAR::isError($result)) {
                    return $this->raiseError($result, null, null,
                        'on demand sequence '.$seq_name.' could not be created', __FUNCTION__);
                } else {
                    return $this->nextID($seq_name, false);
                }
            }
            return $result;
        }
        $value = $this->lastInsertID();
        if (is_numeric($value)) {
            $query = "DELETE FROM $sequence_name WHERE $seqcol_name < $value";
            $result =& $this->_doQuery($query, true);
            if (PEAR::isError($result)) {
                $this->warnings[] = 'nextID: could not delete previous sequence table values from '.$seq_name;
            }
        }
        return $value;
    }

    // }}}
    // {{{ lastInsertID()

    /**
     * Returns the autoincrement ID if supported or $id or fetches the current
     * ID in a sequence called: $table.(empty($field) ? '' : '_'.$field)
     *
     * @param string $table name of the table into which a new row was inserted
     * @param string $field name of the field into which a new row was inserted
     * @return mixed MDB2 Error Object or id
     * @access public
     */
    function lastInsertID($table = null, $field = null)
    {
        $connection = $this->getConnection();
        if (PEAR::isError($connection)) {
            return $connection;
        }
        $value = @sqlite_last_insert_rowid($connection);
        if (!$value) {
            return $this->raiseError(null, null, null,
                'Could not get last insert ID', __FUNCTION__);
        }
        return $value;
    }

    // }}}
    // {{{ currID()

    /**
     * Returns the current id of a sequence
     *
     * @param string $seq_name name of the sequence
     * @return mixed MDB2 Error Object or id
     * @access public
     */
    function currID($seq_name)
    {
        $sequence_name = $this->quoteIdentifier($this->getSequenceName($seq_name), true);
        $seqcol_name = $this->quoteIdentifier($this->options['seqcol_name'], true);
        $query = "SELECT MAX($seqcol_name) FROM $sequence_name";
        return $this->queryOne($query, 'integer');
    }
}

/**
 * MDB2 SQLite result driver
 *
 * @package MDB2
 * @category Database
 * @author  Lukas Smith <smith@pooteeweet.org>
 */
class MDB2_Result_sqlite extends MDB2_Result_Common
{
    // }}}
    // {{{ fetchRow()

    /**
     * Fetch a row and insert the data into an existing array.
     *
     * @param int       $fetchmode  how the array data should be indexed
     * @param int    $rownum    number of the row where the data can be found
     * @return int data array on success, a MDB2 error on failure
     * @access public
     */
    function &fetchRow($fetchmode = MDB2_FETCHMODE_DEFAULT, $rownum = null)
    {
        if (!is_null($rownum)) {
            $seek = $this->seek($rownum);
            if (PEAR::isError($seek)) {
                return $seek;
            }
        }
        if ($fetchmode == MDB2_FETCHMODE_DEFAULT) {
            $fetchmode = $this->db->fetchmode;
        }
        if ($fetchmode & MDB2_FETCHMODE_ASSOC) {
            $row = @sqlite_fetch_array($this->result, SQLITE_ASSOC);
            if (is_array($row)
                && $this->db->options['portability'] & MDB2_PORTABILITY_FIX_CASE
            ) {
                $row = array_change_key_case($row, $this->db->options['field_case']);
            }
        } else {
           $row = @sqlite_fetch_array($this->result, SQLITE_NUM);
        }
        if (!$row) {
            if ($this->result === false) {
                $err =& $this->db->raiseError(MDB2_ERROR_NEED_MORE_DATA, null, null,
                    'resultset has already been freed', __FUNCTION__);
                return $err;
            }
            $null = null;
            return $null;
        }
        $mode = $this->db->options['portability'] & MDB2_PORTABILITY_EMPTY_TO_NULL;
        $rtrim = false;
        if ($this->db->options['portability'] & MDB2_PORTABILITY_RTRIM) {
            if (empty($this->types)) {
                $mode += MDB2_PORTABILITY_RTRIM;
            } else {
                $rtrim = true;
            }
        }
        if ($mode) {
            $this->db->_fixResultArrayValues($row, $mode);
        }
        if (!empty($this->types)) {
            $row = $this->db->datatype->convertResultRow($this->types, $row, $rtrim);
        }
        if (!empty($this->values)) {
            $this->_assignBindColumns($row);
        }
        if ($fetchmode === MDB2_FETCHMODE_OBJECT) {
            $object_class = $this->db->options['fetch_class'];
            if ($object_class == 'stdClass') {
                $row = (object) $row;
            } else {
                $row = &new $object_class($row);
            }
        }
        ++$this->rownum;
        return $row;
    }

    // }}}
    // {{{ _getColumnNames()

    /**
     * Retrieve the names of columns returned by the DBMS in a query result.
     *
     * @return  mixed   Array variable that holds the names of columns as keys
     *                  or an MDB2 error on failure.
     *                  Some DBMS may not return any columns when the result set
     *                  does not contain any rows.
     * @access private
     */
    function _getColumnNames()
    {
        $columns = array();
        $numcols = $this->numCols();
        if (PEAR::isError($numcols)) {
            return $numcols;
        }
        for ($column = 0; $column < $numcols; $column++) {
            $column_name = @sqlite_field_name($this->result, $column);
            $columns[$column_name] = $column;
        }
        if ($this->db->options['portability'] & MDB2_PORTABILITY_FIX_CASE) {
            $columns = array_change_key_case($columns, $this->db->options['field_case']);
        }
        return $columns;
    }

    // }}}
    // {{{ numCols()

    /**
     * Count the number of columns returned by the DBMS in a query result.
     *
     * @access public
     * @return mixed integer value with the number of columns, a MDB2 error
     *                       on failure
     */
    function numCols()
    {
        $cols = @sqlite_num_fields($this->result);
        if (is_null($cols)) {
            if ($this->result === false) {
                return $this->db->raiseError(MDB2_ERROR_NEED_MORE_DATA, null, null,
                    'resultset has already been freed', __FUNCTION__);
            } elseif (is_null($this->result)) {
                return count($this->types);
            }
            return $this->db->raiseError(null, null, null,
                'Could not get column count', __FUNCTION__);
        }
        return $cols;
    }
}

/**
 * MDB2 SQLite buffered result driver
 *
 * @package MDB2
 * @category Database
 * @author  Lukas Smith <smith@pooteeweet.org>
 */
class MDB2_BufferedResult_sqlite extends MDB2_Result_sqlite
{
    // {{{ seek()

    /**
     * Seek to a specific row in a result set
     *
     * @param int    $rownum    number of the row where the data can be found
     * @return mixed MDB2_OK on success, a MDB2 error on failure
     * @access public
     */
    function seek($rownum = 0)
    {
        if (!@sqlite_seek($this->result, $rownum)) {
            if ($this->result === false) {
                return $this->db->raiseError(MDB2_ERROR_NEED_MORE_DATA, null, null,
                    'resultset has already been freed', __FUNCTION__);
            } elseif (is_null($this->result)) {
                return MDB2_OK;
            }
            return $this->db->raiseError(MDB2_ERROR_INVALID, null, null,
                'tried to seek to an invalid row number ('.$rownum.')', __FUNCTION__);
        }
        $this->rownum = $rownum - 1;
        return MDB2_OK;
    }

    // }}}
    // {{{ valid()

    /**
     * Check if the end of the result set has been reached
     *
     * @return mixed true or false on sucess, a MDB2 error on failure
     * @access public
     */
    function valid()
    {
        $numrows = $this->numRows();
        if (PEAR::isError($numrows)) {
            return $numrows;
        }
        return $this->rownum < ($numrows - 1);
    }

    // }}}
    // {{{ numRows()

    /**
     * Returns the number of rows in a result object
     *
     * @return mixed MDB2 Error Object or the number of rows
     * @access public
     */
    function numRows()
    {
        $rows = @sqlite_num_rows($this->result);
        if (is_null($rows)) {
            if ($this->result === false) {
                return $this->db->raiseError(MDB2_ERROR_NEED_MORE_DATA, null, null,
                    'resultset has already been freed', __FUNCTION__);
            } elseif (is_null($this->result)) {
                return 0;
            }
            return $this->db->raiseError(null, null, null,
                'Could not get row count', __FUNCTION__);
        }
        return $rows;
    }
}

/**
 * MDB2 SQLite statement driver
 *
 * @package MDB2
 * @category Database
 * @author  Lukas Smith <smith@pooteeweet.org>
 */
class MDB2_Statement_sqlite extends MDB2_Statement_Common
{

}

?>