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<?php

/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/**

 * The PEAR DB driver for PHP's sqlite extension

 * for interacting with SQLite databases

 *

 * PHP version 5

 *

 * LICENSE: This source file is subject to version 3.0 of the PHP license

 * that is available through the world-wide-web at the following URI:

 * http://www.php.net/license/3_0.txt.  If you did not receive a copy of

 * the PHP License and are unable to obtain it through the web, please

 * send a note to license@php.net so we can mail you a copy immediately.

 *

 * @category   Database

 * @package    DB

 * @author     Urs Gehrig <urs@circle.ch>

 * @author     Mika Tuupola <tuupola@appelsiini.net>

 * @author     Daniel Convissor <danielc@php.net>

 * @copyright  1997-2007 The PHP Group

 * @license    http://www.php.net/license/3_0.txt  PHP License 3.0 3.0

 * @version    CVS: $Id$

 * @link       http://pear.php.net/package/DB

 */

/**

 * Obtain the DB_common class so it can be extended from

 */

require_once 'DB/common.php';

/**

 * The methods PEAR DB uses to interact with PHP's sqlite extension

 * for interacting with SQLite databases

 *

 * These methods overload the ones declared in DB_common.

 *

 * NOTICE:  This driver needs PHP's track_errors ini setting to be on.

 * It is automatically turned on when connecting to the database.

 * Make sure your scripts don't turn it off.

 *

 * @category   Database

 * @package    DB

 * @author     Urs Gehrig <urs@circle.ch>

 * @author     Mika Tuupola <tuupola@appelsiini.net>

 * @author     Daniel Convissor <danielc@php.net>

 * @copyright  1997-2007 The PHP Group

 * @license    http://www.php.net/license/3_0.txt  PHP License 3.0 3.0

 * @version    Release: 1.9.2

 * @link       http://pear.php.net/package/DB

 */

class DB_sqlite extends DB_common

{

    // {{{ properties

    /**

     * The DB driver type (mysql, oci8, odbc, etc.)

     * @var string

     */

    var $phptype = 'sqlite';

    /**

     * The database syntax variant to be used (db2, access, etc.), if any

     * @var string

     */

    var $dbsyntax = 'sqlite';

    /**

     * The capabilities of this DB implementation

     *

     * The 'new_link' element contains the PHP version that first provided

     * new_link support for this DBMS.  Contains false if it's unsupported.

     *

     * Meaning of the 'limit' element:

     *   + 'emulate' = emulate with fetch row by number

     *   + 'alter'   = alter the query

     *   + false     = skip rows

     *

     * @var array

     */

    var $features = array(

        'limit'         => 'alter',

        'new_link'      => false,

        'numrows'       => true,

        'pconnect'      => true,

        'prepare'       => false,

        'ssl'           => false,

        'transactions'  => false,

    );

    /**

     * A mapping of native error codes to DB error codes

     *

     * {@internal  Error codes according to sqlite_exec.  See the online

     * manual at http://sqlite.org/c_interface.html for info.

     * This error handling based on sqlite_exec is not yet implemented.}}

     *

     * @var array

     */

    var $errorcode_map = array(

    );

    /**

     * The raw database connection created by PHP

     * @var resource

     */

    var $connection;

    /**

     * The DSN information for connecting to a database

     * @var array

     */

    var $dsn = array();

    /**

     * SQLite data types

     *

     * @link http://www.sqlite.org/datatypes.html

     *

     * @var array

     */

    var $keywords = array (

        'BLOB'      => '',

        'BOOLEAN'   => '',

        'CHARACTER' => '',

        'CLOB'      => '',

        'FLOAT'     => '',

        'INTEGER'   => '',

        'KEY'       => '',

        'NATIONAL'  => '',

        'NUMERIC'   => '',

        'NVARCHAR'  => '',

        'PRIMARY'   => '',

        'TEXT'      => '',

        'TIMESTAMP' => '',

        'UNIQUE'    => '',

        'VARCHAR'   => '',

        'VARYING'   => '',

    );

    /**

     * The most recent error message from $php_errormsg

     * @var string

     * @access private

     */

    var $_lasterror = '';

    // }}}

    // {{{ constructor

    /**

     * This constructor calls <kbd>parent::__construct()</kbd>

     *

     * @return void

     */

    function __construct()

    {

        parent::__construct();

    }

    // }}}

    // {{{ connect()

    /**

     * Connect to the database server, log in and open the database

     *

     * Don't call this method directly.  Use DB::connect() instead.

     *

     * PEAR DB's sqlite driver supports the following extra DSN options:

     *   + mode  The permissions for the database file, in four digit

     *            chmod octal format (eg "0600").

     *

     * Example of connecting to a database in read-only mode:

     * <code>

     * require_once 'DB.php';

     *

     * $dsn = 'sqlite:///path/and/name/of/db/file?mode=0400';

     * $options = array(

     *     'portability' => DB_PORTABILITY_ALL,

     * );

     *

     * $db = DB::connect($dsn, $options);

     * if (PEAR::isError($db)) {

     *     die($db->getMessage());

     * }

     * </code>

     *

     * @param array $dsn         the data source name

     * @param bool  $persistent  should the connection be persistent?

     *

     * @return int  DB_OK on success. A DB_Error object on failure.

     */

    function connect($dsn, $persistent = false)

    {

        if (!PEAR::loadExtension('sqlite')) {

            return $this->raiseError(DB_ERROR_EXTENSION_NOT_FOUND);

        }

        $this->dsn = $dsn;

        if ($dsn['dbsyntax']) {

            $this->dbsyntax = $dsn['dbsyntax'];

        }

        if (!$dsn['database']) {

            return $this->sqliteRaiseError(DB_ERROR_ACCESS_VIOLATION);

        }

        if ($dsn['database'] !== ':memory:') {

            if (!file_exists($dsn['database'])) {

                if (!touch($dsn['database'])) {

                    return $this->sqliteRaiseError(DB_ERROR_NOT_FOUND);

                }

                if (!isset($dsn['mode']) ||

                    !is_numeric($dsn['mode']))

                {

                    $mode = 0644;

                } else {

                    $mode = octdec($dsn['mode']);

                }

                if (!chmod($dsn['database'], $mode)) {

                    return $this->sqliteRaiseError(DB_ERROR_NOT_FOUND);

                }

                if (!file_exists($dsn['database'])) {

                    return $this->sqliteRaiseError(DB_ERROR_NOT_FOUND);

                }

            }

            if (!is_file($dsn['database'])) {

                return $this->sqliteRaiseError(DB_ERROR_INVALID);

            }

            if (!is_readable($dsn['database'])) {

                return $this->sqliteRaiseError(DB_ERROR_ACCESS_VIOLATION);

            }

        }

        $connect_function = $persistent ? 'sqlite_popen' : 'sqlite_open';

        // track_errors must remain on for simpleQuery()

        @ini_set('track_errors', 1);

        $php_errormsg = '';

        if (!$this->connection = @$connect_function($dsn['database'])) {

            return $this->raiseError(DB_ERROR_NODBSELECTED,

                                     null, null, null,

                                     $php_errormsg);

        }

        return DB_OK;

    }

    // }}}

    // {{{ disconnect()

    /**

     * Disconnects from the database server

     *

     * @return bool  TRUE on success, FALSE on failure

     */

    function disconnect()

    {

        $ret = @sqlite_close($this->connection);

        $this->connection = null;

        return $ret;

    }

    // }}}

    // {{{ simpleQuery()

    /**

     * Sends a query to the database server

     *

     * NOTICE:  This method needs PHP's track_errors ini setting to be on.

     * It is automatically turned on when connecting to the database.

     * Make sure your scripts don't turn it off.

     *

     * @param string  the SQL query string

     *

     * @return mixed  + a PHP result resrouce for successful SELECT queries

     *                + the DB_OK constant for other successful queries

     *                + a DB_Error object on failure

     */

    function simpleQuery($query)

    {

        $ismanip = $this->_checkManip($query);

        $this->last_query = $query;

        $query = $this->modifyQuery($query);

        $php_errormsg = '';

        $result = @sqlite_query($query, $this->connection);

        $this->_lasterror = $php_errormsg ? $php_errormsg : '';

        $this->result = $result;

        if (!$this->result) {

            return $this->sqliteRaiseError(null);

        }

        // sqlite_query() seems to allways return a resource

        // so cant use that. Using $ismanip instead

        if (!$ismanip) {

            $numRows = $this->numRows($result);

            if (is_object($numRows)) {

                // we've got PEAR_Error

                return $numRows;

            }

            return $result;

        }

        return DB_OK;

    }

    // }}}

    // {{{ nextResult()

    /**

     * Move the internal sqlite result pointer to the next available result

     *

     * @param resource $result  the valid sqlite result resource

     *

     * @return bool  true if a result is available otherwise return false

     */

    function nextResult($result)

    {

        return false;

    }

    // }}}

    // {{{ fetchInto()

    /**

     * Places a row from the result set into the given array

     *

     * Formating of the array and the data therein are configurable.

     * See DB_result::fetchInto() for more information.

     *

     * This method is not meant to be called directly.  Use

     * DB_result::fetchInto() instead.  It can't be declared "protected"

     * because DB_result is a separate object.

     *

     * @param resource $result    the query result resource

     * @param array    $arr       the referenced array to put the data in

     * @param int      $fetchmode how the resulting array should be indexed

     * @param int      $rownum    the row number to fetch (0 = first row)

     *

     * @return mixed  DB_OK on success, NULL when the end of a result set is

     *                 reached or on failure

     *

     * @see DB_result::fetchInto()

     */

    function fetchInto($result, &$arr, $fetchmode, $rownum = null)

    {

        if ($rownum !== null) {

            if (!@sqlite_seek($this->result, $rownum)) {

                return null;

            }

        }

        if ($fetchmode & DB_FETCHMODE_ASSOC) {

            $arr = @sqlite_fetch_array($result, SQLITE_ASSOC);

            if ($this->options['portability'] & DB_PORTABILITY_LOWERCASE && $arr) {

                $arr = array_change_key_case($arr, CASE_LOWER);

            }

            /* Remove extraneous " characters from the fields in the result.

             * Fixes bug #11716. */

            if (is_array($arr) && count($arr) > 0) {

                $strippedArr = array();

                foreach ($arr as $field => $value) {

                    $strippedArr[trim($field, '"')] = $value;

                }

                $arr = $strippedArr;

            }

        } else {

            $arr = @sqlite_fetch_array($result, SQLITE_NUM);

        }

        if (!$arr) {

            return null;

        }

        if ($this->options['portability'] & DB_PORTABILITY_RTRIM) {

            /*

             * Even though this DBMS already trims output, we do this because

             * a field might have intentional whitespace at the end that

             * gets removed by DB_PORTABILITY_RTRIM under another driver.

             */

            $this->_rtrimArrayValues($arr);

        }

        if ($this->options['portability'] & DB_PORTABILITY_NULL_TO_EMPTY) {

            $this->_convertNullArrayValuesToEmpty($arr);

        }

        return DB_OK;

    }

    // }}}

    // {{{ freeResult()

    /**

     * Deletes the result set and frees the memory occupied by the result set

     *

     * This method is not meant to be called directly.  Use

     * DB_result::free() instead.  It can't be declared "protected"

     * because DB_result is a separate object.

     *

     * @param resource $result  PHP's query result resource

     *

     * @return bool  TRUE on success, FALSE if $result is invalid

     *

     * @see DB_result::free()

     */

    function freeResult(&$result)

    {

        // XXX No native free?

        if (!is_resource($result)) {

            return false;

        }

        $result = null;

        return true;

    }

    // }}}

    // {{{ numCols()

    /**

     * Gets the number of columns in a result set

     *

     * This method is not meant to be called directly.  Use

     * DB_result::numCols() instead.  It can't be declared "protected"

     * because DB_result is a separate object.

     *

     * @param resource $result  PHP's query result resource

     *

     * @return int  the number of columns.  A DB_Error object on failure.

     *

     * @see DB_result::numCols()

     */

    function numCols($result)

    {

        $cols = @sqlite_num_fields($result);

        if (!$cols) {

            return $this->sqliteRaiseError();

        }

        return $cols;

    }

    // }}}

    // {{{ numRows()

    /**

     * Gets the number of rows in a result set

     *

     * This method is not meant to be called directly.  Use

     * DB_result::numRows() instead.  It can't be declared "protected"

     * because DB_result is a separate object.

     *

     * @param resource $result  PHP's query result resource

     *

     * @return int  the number of rows.  A DB_Error object on failure.

     *

     * @see DB_result::numRows()

     */

    function numRows($result)

    {

        $rows = @sqlite_num_rows($result);

        if ($rows === null) {

            return $this->sqliteRaiseError();

        }

        return $rows;

    }

    // }}}

    // {{{ affected()

    /**

     * Determines the number of rows affected by a data maniuplation query

     *

     * 0 is returned for queries that don't manipulate data.

     *

     * @return int  the number of rows.  A DB_Error object on failure.

     */

    function affectedRows()

    {

        return @sqlite_changes($this->connection);

    }

    // }}}

    // {{{ dropSequence()

    /**

     * Deletes a sequence

     *

     * @param string $seq_name  name of the sequence to be deleted

     *

     * @return int  DB_OK on success.  A DB_Error object on failure.

     *

     * @see DB_common::dropSequence(), DB_common::getSequenceName(),

     *      DB_sqlite::nextID(), DB_sqlite::createSequence()

     */

    function dropSequence($seq_name)

    {

        return $this->query('DROP TABLE ' . $this->getSequenceName($seq_name));

    }

    /**

     * Creates a new sequence

     *

     * @param string $seq_name  name of the new sequence

     *

     * @return int  DB_OK on success.  A DB_Error object on failure.

     *

     * @see DB_common::createSequence(), DB_common::getSequenceName(),

     *      DB_sqlite::nextID(), DB_sqlite::dropSequence()

     */

    function createSequence($seq_name)

    {

        $seqname = $this->getSequenceName($seq_name);

        $query   = 'CREATE TABLE ' . $seqname .

                   ' (id INTEGER UNSIGNED PRIMARY KEY) ';

        $result  = $this->query($query);

        if (DB::isError($result)) {

            return($result);

        }

        $query   = "CREATE TRIGGER ${seqname}_cleanup AFTER INSERT ON $seqname

                    BEGIN

                        DELETE FROM $seqname WHERE id<LAST_INSERT_ROWID();

                    END ";

        $result  = $this->query($query);

        if (DB::isError($result)) {

            return($result);

        }

    }

    // }}}

    // {{{ nextId()

    /**

     * Returns the next free id in a sequence

     *

     * @param string  $seq_name  name of the sequence

     * @param boolean $ondemand  when true, the seqence is automatically

     *                            created if it does not exist

     *

     * @return int  the next id number in the sequence.

     *               A DB_Error object on failure.

     *

     * @see DB_common::nextID(), DB_common::getSequenceName(),

     *      DB_sqlite::createSequence(), DB_sqlite::dropSequence()

     */

    function nextId($seq_name, $ondemand = true)

    {

        $seqname = $this->getSequenceName($seq_name);

        do {

            $repeat = 0;

            $this->pushErrorHandling(PEAR_ERROR_RETURN);

            $result = $this->query("INSERT INTO $seqname (id) VALUES (NULL)");

            $this->popErrorHandling();

            if ($result === DB_OK) {

                $id = @sqlite_last_insert_rowid($this->connection);

                if ($id != 0) {

                    return $id;

                }

            } elseif ($ondemand && DB::isError($result) &&

                      $result->getCode() == DB_ERROR_NOSUCHTABLE)

            {

                $result = $this->createSequence($seq_name);

                if (DB::isError($result)) {

                    return $this->raiseError($result);

                } else {

                    $repeat = 1;

                }

            }

        } while ($repeat);

        return $this->raiseError($result);

    }

    // }}}

    // {{{ getDbFileStats()

    /**

     * Get the file stats for the current database

     *

     * Possible arguments are dev, ino, mode, nlink, uid, gid, rdev, size,

     * atime, mtime, ctime, blksize, blocks or a numeric key between

     * 0 and 12.

     *

     * @param string $arg  the array key for stats()

     *

     * @return mixed  an array on an unspecified key, integer on a passed

     *                arg and false at a stats error

     */

    function getDbFileStats($arg = '')

    {

        $stats = stat($this->dsn['database']);

        if ($stats == false) {

            return false;

        }

        if (is_array($stats)) {

            if (is_numeric($arg)) {

                if (((int)$arg <= 12) & ((int)$arg >= 0)) {

                    return false;

                }

                return $stats[$arg ];

            }

            if (array_key_exists(trim($arg), $stats)) {

                return $stats[$arg ];

            }

        }

        return $stats;

    }

    // }}}

    // {{{ escapeSimple()

    /**

     * Escapes a string according to the current DBMS's standards

     *

     * In SQLite, this makes things safe for inserts/updates, but may

     * cause problems when performing text comparisons against columns

     * containing binary data. See the

     * {@link http://php.net/sqlite_escape_string PHP manual} for more info.

     *

     * @param string $str  the string to be escaped

     *

     * @return string  the escaped string

     *

     * @since Method available since Release 1.6.1

     * @see DB_common::escapeSimple()

     */

    function escapeSimple($str)

    {

        return @sqlite_escape_string($str);

    }

    // }}}

    // {{{ modifyLimitQuery()

    /**

     * Adds LIMIT clauses to a query string according to current DBMS standards

     *

     * @param string $query   the query to modify

     * @param int    $from    the row to start to fetching (0 = the first row)

     * @param int    $count   the numbers of rows to fetch

     * @param mixed  $params  array, string or numeric data to be used in

     *                         execution of the statement.  Quantity of items

     *                         passed must match quantity of placeholders in

     *                         query:  meaning 1 placeholder for non-array

     *                         parameters or 1 placeholder per array element.

     *

     * @return string  the query string with LIMIT clauses added

     *

     * @access protected

     */

    function modifyLimitQuery($query, $from, $count, $params = array())

    {

        return "$query LIMIT $count OFFSET $from";

    }

    // }}}

    // {{{ modifyQuery()

    /**

     * Changes a query string for various DBMS specific reasons

     *

     * This little hack lets you know how many rows were deleted

     * when running a "DELETE FROM table" query.  Only implemented

     * if the DB_PORTABILITY_DELETE_COUNT portability option is on.

     *

     * @param string $query  the query string to modify

     *

     * @return string  the modified query string

     *

     * @access protected

     * @see DB_common::setOption()

     */

    function modifyQuery($query)

    {

        if ($this->options['portability'] & DB_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);

            }

        }

        return $query;

    }

    // }}}

    // {{{ sqliteRaiseError()

    /**

     * Produces a DB_Error object regarding the current problem

     *

     * @param int $errno  if the error is being manually raised pass a

     *                     DB_ERROR* constant here.  If this isn't passed

     *                     the error information gathered from the DBMS.

     *

     * @return object  the DB_Error object

     *

     * @see DB_common::raiseError(),

     *      DB_sqlite::errorNative(), DB_sqlite::errorCode()

     */

    function sqliteRaiseError($errno = null)

    {

        $native = $this->errorNative();

        if ($errno === null) {

            $errno = $this->errorCode($native);

        }

        $errorcode = @sqlite_last_error($this->connection);

        $userinfo = "$errorcode ** $this->last_query";

        return $this->raiseError($errno, null, null, $userinfo, $native);

    }

    // }}}

    // {{{ errorNative()

    /**

     * Gets the DBMS' native error message produced by the last query

     *

     * {@internal This is used to retrieve more meaningfull error messages

     * because sqlite_last_error() does not provide adequate info.}}

     *

     * @return string  the DBMS' error message

     */

    function errorNative()

    {

        return $this->_lasterror;

    }

    // }}}

    // {{{ errorCode()

    /**

     * Determines PEAR::DB error code from the database's text error message

     *

     * @param string $errormsg  the error message returned from the database

     *

     * @return integer  the DB error number

     */

    function errorCode($errormsg)

    {

        static $error_regexps;

        // PHP 5.2+ prepends the function name to $php_errormsg, so we need

        // this hack to work around it, per bug #9599.

        $errormsg = preg_replace('/^sqlite[a-z_]+\(\): /', '', $errormsg);

        if (!isset($error_regexps)) {

            $error_regexps = array(

                '/^no such table:/' => DB_ERROR_NOSUCHTABLE,

                '/^no such index:/' => DB_ERROR_NOT_FOUND,

                '/^(table|index) .* already exists$/' => DB_ERROR_ALREADY_EXISTS,

                '/PRIMARY KEY must be unique/i' => DB_ERROR_CONSTRAINT,

                '/is not unique/' => DB_ERROR_CONSTRAINT,

                '/columns .* are not unique/i' => DB_ERROR_CONSTRAINT,

                '/uniqueness constraint failed/' => DB_ERROR_CONSTRAINT,

                '/may not be NULL/' => DB_ERROR_CONSTRAINT_NOT_NULL,

                '/^no such column:/' => DB_ERROR_NOSUCHFIELD,

                '/no column named/' => DB_ERROR_NOSUCHFIELD,

                '/column not present in both tables/i' => DB_ERROR_NOSUCHFIELD,

                '/^near ".*": syntax error$/' => DB_ERROR_SYNTAX,

                '/[0-9]+ values for [0-9]+ columns/i' => DB_ERROR_VALUE_COUNT_ON_ROW,

            );

        }

        foreach ($error_regexps as $regexp => $code) {

            if (preg_match($regexp, $errormsg)) {

                return $code;

            }

        }

        // Fall back to DB_ERROR if there was no mapping.

        return DB_ERROR;

    }

    // }}}

    // {{{ tableInfo()

    /**

     * Returns information about a table

     *

     * @param string         $result  a string containing the name of a table

     * @param int            $mode    a valid tableInfo mode

     *

     * @return array  an associative array with the information requested.

     *                 A DB_Error object on failure.

     *

     * @see DB_common::tableInfo()

     * @since Method available since Release 1.7.0

     */

    function tableInfo($result, $mode = null)

    {

        if (is_string($result)) {

            /*

             * Probably received a table name.

             * Create a result resource identifier.

             */

            $id = @sqlite_array_query($this->connection,

                                      "PRAGMA table_info('$result');",

                                      SQLITE_ASSOC);

            $got_string = true;

        } else {

            $this->last_query = '';

            return $this->raiseError(DB_ERROR_NOT_CAPABLE, null, null, null,

                                     'This DBMS can not obtain tableInfo' .

                                     ' from result sets');

        }

        if ($this->options['portability'] & DB_PORTABILITY_LOWERCASE) {

            $case_func = 'strtolower';

        } else {

            $case_func = 'strval';

        }

        $count = count($id);

        $res   = array();

        if ($mode) {

            $res['num_fields'] = $count;

        }

        for ($i = 0; $i < $count; $i++) {

            if (strpos($id[$i]['type'], '(') !== false) {

                $bits = explode('(', $id[$i]['type']);

                $type = $bits[0];

                $len  = rtrim($bits[1],')');

            } else {

                $type = $id[$i]['type'];

                $len  = 0;

            }

            $flags = '';

            if ($id[$i]['pk']) {

                $flags .= 'primary_key ';

                if (strtoupper($type) == 'INTEGER') {

                    $flags .= 'auto_increment ';

                }

            }

            if ($id[$i]['notnull']) {

                $flags .= 'not_null ';

            }

            if ($id[$i]['dflt_value'] !== null) {

                $flags .= 'default_' . rawurlencode($id[$i]['dflt_value']);

            }

            $flags = trim($flags);

            $res[$i] = array(

                'table' => $case_func($result),

                'name'  => $case_func($id[$i]['name']),

                'type'  => $type,

                'len'   => $len,

                'flags' => $flags,

            );

            if ($mode & DB_TABLEINFO_ORDER) {

                $res['order'][$res[$i]['name']] = $i;

            }

            if ($mode & DB_TABLEINFO_ORDERTABLE) {

                $res['ordertable'][$res[$i]['table']][$res[$i]['name']] = $i;

            }

        }

        return $res;

    }

    // }}}

    // {{{ getSpecialQuery()

    /**

     * Obtains the query string needed for listing a given type of objects

     *

     * @param string $type  the kind of objects you want to retrieve

     * @param array  $args  SQLITE DRIVER ONLY: a private array of arguments

     *                       used by the getSpecialQuery().  Do not use

     *                       this directly.

     *

     * @return string  the SQL query string or null if the driver doesn't

     *                  support the object type requested

     *

     * @access protected

     * @see DB_common::getListOf()

     */

    function getSpecialQuery($type, $args = array())

    {

        if (!is_array($args)) {

            return $this->raiseError('no key specified', null, null, null,

                                     'Argument has to be an array.');

        }

        switch ($type) {

            case 'master':

                return 'SELECT * FROM sqlite_master;';

            case 'tables':

                return "SELECT name FROM sqlite_master WHERE type='table' "

                       . 'UNION ALL SELECT name FROM sqlite_temp_master '

                       . "WHERE type='table' ORDER BY name;";

            case 'schema':

                return 'SELECT sql FROM (SELECT * FROM sqlite_master '

                       . 'UNION ALL SELECT * FROM sqlite_temp_master) '

                       . "WHERE type!='meta' "

                       . 'ORDER BY tbl_name, type DESC, name;';

            case 'schemax':

            case 'schema_x':

                /*

                 * Use like:

                 * $res = $db->query($db->getSpecialQuery('schema_x',

                 *                   array('table' => 'table3')));

                 */

                return 'SELECT sql FROM (SELECT * FROM sqlite_master '

                       . 'UNION ALL SELECT * FROM sqlite_temp_master) '

                       . "WHERE tbl_name LIKE '{$args['table']}' "

                       . "AND type!='meta' "

                       . 'ORDER BY type DESC, name;';

            case 'alter':

                /*

                 * SQLite does not support ALTER TABLE; this is a helper query

                 * to handle this. 'table' represents the table name, 'rows'

                 * the news rows to create, 'save' the row(s) to keep _with_

                 * the data.

                 *

                 * Use like:

                 * $args = array(

                 *     'table' => $table,

                 *     'rows'  => "id INTEGER PRIMARY KEY, firstname TEXT, surname TEXT, datetime TEXT",

                 *     'save'  => "NULL, titel, content, datetime"

                 * );

                 * $res = $db->query( $db->getSpecialQuery('alter', $args));

                 */

                $rows = strtr($args['rows'], $this->keywords);

                $q = array(

                    'BEGIN TRANSACTION',

                    "CREATE TEMPORARY TABLE {$args['table']}_backup ({$args['rows']})",

                    "INSERT INTO {$args['table']}_backup SELECT {$args['save']} FROM {$args['table']}",

                    "DROP TABLE {$args['table']}",

                    "CREATE TABLE {$args['table']} ({$args['rows']})",

                    "INSERT INTO {$args['table']} SELECT {$rows} FROM {$args['table']}_backup",

                    "DROP TABLE {$args['table']}_backup",

                    'COMMIT',

                );

                /*

                 * This is a dirty hack, since the above query will not get

                 * executed with a single query call so here the query method

                 * will be called directly and return a select instead.

                 */

                foreach ($q as $query) {

                    $this->query($query);

                }

                return "SELECT * FROM {$args['table']};";

            default:

                return null;

        }

    }

    // }}}

}

/*

 * Local variables:

 * tab-width: 4

 * c-basic-offset: 4

 * End:

 */

?>