gnu-social/extlib/DB/ibase.php

<?php

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

/**
 * The PEAR DB driver for PHP's interbase extension
 * for interacting with Interbase and Firebird databases
 *
 * While this class works with PHP 4, PHP's InterBase extension is
 * unstable in PHP 4.  Use PHP 5.
 *
 * 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     Sterling Hughes <sterling@php.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
 * @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';
require_once 'common.php';

/**
 * The methods PEAR DB uses to interact with PHP's interbase extension
 * for interacting with Interbase and Firebird databases
 *
 * These methods overload the ones declared in DB_common.
 *
 * While this class works with PHP 4, PHP's InterBase extension is
 * unstable in PHP 4.  Use PHP 5.
 *
 * NOTICE:  limitQuery() only works for Firebird.
 *
 * @category   Database
 * @package    DB
 * @author     Sterling Hughes <sterling@php.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
 * @version    Release: 1.9.2
 * @link       http://pear.php.net/package/DB
 * @since      Class became stable in Release 1.7.0
 */
class DB_ibase extends DB_common
{
    // {{{ properties

    /**
     * The DB driver type (mysql, oci8, odbc, etc.)
     * @var string
     */
    public $phptype = 'ibase';

    /**
     * The database syntax variant to be used (db2, access, etc.), if any
     * @var string
     */
    public $dbsyntax = 'ibase';

    /**
     * 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
     *
     * NOTE: only firebird supports limit.
     *
     * @var array
     */
    public $features = array(
        'limit' => false,
        'new_link' => false,
        'numrows' => 'emulate',
        'pconnect' => true,
        'prepare' => true,
        'ssl' => false,
        'transactions' => true,
    );

    /**
     * A mapping of native error codes to DB error codes
     * @var array
     */
    public $errorcode_map = array(
        -104 => DB_ERROR_SYNTAX,
        -150 => DB_ERROR_ACCESS_VIOLATION,
        -151 => DB_ERROR_ACCESS_VIOLATION,
        -155 => DB_ERROR_NOSUCHTABLE,
        -157 => DB_ERROR_NOSUCHFIELD,
        -158 => DB_ERROR_VALUE_COUNT_ON_ROW,
        -170 => DB_ERROR_MISMATCH,
        -171 => DB_ERROR_MISMATCH,
        -172 => DB_ERROR_INVALID,
        // -204 =>  // Covers too many errors, need to use regex on msg
        -205 => DB_ERROR_NOSUCHFIELD,
        -206 => DB_ERROR_NOSUCHFIELD,
        -208 => DB_ERROR_INVALID,
        -219 => DB_ERROR_NOSUCHTABLE,
        -297 => DB_ERROR_CONSTRAINT,
        -303 => DB_ERROR_INVALID,
        -413 => DB_ERROR_INVALID_NUMBER,
        -530 => DB_ERROR_CONSTRAINT,
        -551 => DB_ERROR_ACCESS_VIOLATION,
        -552 => DB_ERROR_ACCESS_VIOLATION,
        // -607 =>  // Covers too many errors, need to use regex on msg
        -625 => DB_ERROR_CONSTRAINT_NOT_NULL,
        -803 => DB_ERROR_CONSTRAINT,
        -804 => DB_ERROR_VALUE_COUNT_ON_ROW,
        // -902 =>  // Covers too many errors, need to use regex on msg
        -904 => DB_ERROR_CONNECT_FAILED,
        -922 => DB_ERROR_NOSUCHDB,
        -923 => DB_ERROR_CONNECT_FAILED,
        -924 => DB_ERROR_CONNECT_FAILED
    );

    /**
     * The raw database connection created by PHP
     * @var resource
     */
    public $connection;

    /**
     * The DSN information for connecting to a database
     * @var array
     */
    public $dsn = array();


    /**
     * The number of rows affected by a data manipulation query
     * @var integer
     * @access private
     */
    public $affected = 0;

    /**
     * Should data manipulation queries be committed automatically?
     * @var bool
     * @access private
     */
    public $autocommit = true;

    /**
     * The prepared statement handle from the most recently executed statement
     *
     * {@internal  Mainly here because the InterBase/Firebird API is only
     * able to retrieve data from result sets if the statemnt handle is
     * still in scope.}}
     *
     * @var resource
     */
    public $last_stmt;

    /**
     * Is the given prepared statement a data manipulation query?
     * @var array
     * @access private
     */
    public $manip_query = array();


    // }}}
    // {{{ constructor

    /**
     * This constructor calls <kbd>parent::__construct()</kbd>
     *
     * @return void
     */
    public 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 ibase driver supports the following extra DSN options:
     *   + buffers    The number of database buffers to allocate for the
     *                 server-side cache.
     *   + charset    The default character set for a database.
     *   + dialect    The default SQL dialect for any statement
     *                 executed within a connection.  Defaults to the
     *                 highest one supported by client libraries.
     *                 Functional only with InterBase 6 and up.
     *   + role       Functional only with InterBase 5 and up.
     *
     * @param array $dsn the data source name
     * @param bool $persistent should the connection be persistent?
     *
     * @return int|object
     */
    public function connect($dsn, $persistent = false)
    {
        if (!PEAR::loadExtension('interbase')) {
            return $this->raiseError(DB_ERROR_EXTENSION_NOT_FOUND);
        }

        $this->dsn = $dsn;
        if ($dsn['dbsyntax']) {
            $this->dbsyntax = $dsn['dbsyntax'];
        }
        if ($this->dbsyntax == 'firebird') {
            $this->features['limit'] = 'alter';
        }

        $params = array(
            $dsn['hostspec']
                ? ($dsn['hostspec'] . ':' . $dsn['database'])
                : $dsn['database'],
            $dsn['username'] ? $dsn['username'] : null,
            $dsn['password'] ? $dsn['password'] : null,
            isset($dsn['charset']) ? $dsn['charset'] : null,
            isset($dsn['buffers']) ? $dsn['buffers'] : null,
            isset($dsn['dialect']) ? $dsn['dialect'] : null,
            isset($dsn['role']) ? $dsn['role'] : null,
        );

        $connect_function = $persistent ? 'ibase_pconnect' : 'ibase_connect';

        $this->connection = @call_user_func_array($connect_function, $params);
        if (!$this->connection) {
            return $this->ibaseRaiseError(DB_ERROR_CONNECT_FAILED);
        }
        return DB_OK;
    }

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

    /**
     * Produces a DB_Error object regarding the current problem
     *
     * @param int $errno if the error is being manually raised pass a
     *                     DB_ERROR* constant here.  If this isn't passed
     *                     the error information gathered from the DBMS.
     *
     * @return object  the DB_Error object
     *
     * @see DB_common::raiseError(),
     *      DB_ibase::errorNative(), DB_ibase::errorCode()
     */
    public function &ibaseRaiseError($errno = null)
    {
        if ($errno === null) {
            $errno = $this->errorCode($this->errorNative());
        }
        $tmp = $this->raiseError($errno, null, null, null, @ibase_errmsg());
        return $tmp;
    }

    // }}}
    // {{{ simpleQuery()

    /**
     * Maps native error codes to DB's portable ones
     *
     * @param int $nativecode the error code returned by the DBMS
     *
     * @return int  the portable DB error code.  Return DB_ERROR if the
     *               current driver doesn't have a mapping for the
     *               $nativecode submitted.
     *
     * @since Method available since Release 1.7.0
     */
    public function errorCode($nativecode = null)
    {
        if (isset($this->errorcode_map[$nativecode])) {
            return $this->errorcode_map[$nativecode];
        }

        static $error_regexps;
        if (!isset($error_regexps)) {
            $error_regexps = array(
                '/generator .* is not defined/'
                => DB_ERROR_SYNTAX,  // for compat. w ibase_errcode()
                '/violation of [\w ]+ constraint/i'
                => DB_ERROR_CONSTRAINT,
                '/table.*(not exist|not found|unknown)/i'
                => DB_ERROR_NOSUCHTABLE,
                '/table .* already exists/i'
                => DB_ERROR_ALREADY_EXISTS,
                '/unsuccessful metadata update .* failed attempt to store duplicate value/i'
                => DB_ERROR_ALREADY_EXISTS,
                '/unsuccessful metadata update .* not found/i'
                => DB_ERROR_NOT_FOUND,
                '/validation error for column .* value "\*\*\* null/i'
                => DB_ERROR_CONSTRAINT_NOT_NULL,
                '/conversion error from string/i'
                => DB_ERROR_INVALID_NUMBER,
                '/no permission for/i'
                => DB_ERROR_ACCESS_VIOLATION,
                '/arithmetic exception, numeric overflow, or string truncation/i'
                => DB_ERROR_INVALID,
                '/feature is not supported/i'
                => DB_ERROR_NOT_CAPABLE,
            );
        }

        $errormsg = @ibase_errmsg();
        foreach ($error_regexps as $regexp => $code) {
            if (preg_match($regexp, $errormsg)) {
                return $code;
            }
        }
        return DB_ERROR;
    }

    // }}}
    // {{{ modifyLimitQuery()

    /**
     * Gets the DBMS' native error code produced by the last query
     *
     * @return int  the DBMS' error code.  NULL if there is no error code.
     *
     * @since Method available since Release 1.7.0
     */
    public function errorNative()
    {
        if (function_exists('ibase_errcode')) {
            return @ibase_errcode();
        }
        if (preg_match(
            '/^Dynamic SQL Error SQL error code = ([0-9-]+)/i',
            @ibase_errmsg(),
            $m
        )) {
            return (int)$m[1];
        }
        return null;
    }

    // }}}
    // {{{ nextResult()

    /**
     * Disconnects from the database server
     *
     * @return bool  TRUE on success, FALSE on failure
     */
    public function disconnect()
    {
        $ret = @ibase_close($this->connection);
        $this->connection = null;
        return $ret;
    }

    // }}}
    // {{{ fetchInto()

    /**
     * Sends a query to the database server
     *
     * @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
     */
    public function simpleQuery($query)
    {
        $ismanip = $this->_checkManip($query);
        $this->last_query = $query;
        $query = $this->modifyQuery($query);
        $result = @ibase_query($this->connection, $query);

        if (!$result) {
            return $this->ibaseRaiseError();
        }
        if ($this->autocommit && $ismanip) {
            @ibase_commit($this->connection);
        }
        if ($ismanip) {
            $this->affected = $result;
            return DB_OK;
        } else {
            $this->affected = 0;
            return $result;
        }
    }

    // }}}
    // {{{ freeResult()

    /**
     * Adds LIMIT clauses to a query string according to current DBMS standards
     *
     * Only works with Firebird.
     *
     * @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 $params array, string or numeric data to be used in
     *                         execution of the statement.  Quantity of items
     *                         passed must match quantity of placeholders in
     *                         query:  meaning 1 placeholder for non-array
     *                         parameters or 1 placeholder per array element.
     *
     * @return string  the query string with LIMIT clauses added
     *
     * @access protected
     */
    public function modifyLimitQuery($query, $from, $count, $params = array())
    {
        if ($this->dsn['dbsyntax'] == 'firebird') {
            $query = preg_replace(
                '/^([\s(])*SELECT/i',
                "SELECT FIRST $count SKIP $from",
                $query
            );
        }
        return $query;
    }

    // }}}
    // {{{ freeQuery()

    /**
     * Move the internal ibase result pointer to the next available result
     *
     * @param a valid fbsql result resource
     *
     * @access public
     *
     * @return true if a result is available otherwise return false
     */
    public function nextResult($result)
    {
        return false;
    }

    // }}}
    // {{{ affectedRows()

    /**
     * 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 $rownum the row number to fetch (0 = first row)
     *
     * @return mixed  DB_OK on success, NULL when the end of a result set is
     *                 reached or on failure
     *
     * @see DB_result::fetchInto()
     */
    public function fetchInto($result, &$arr, $fetchmode, $rownum = null)
    {
        if ($rownum !== null) {
            return $this->ibaseRaiseError(DB_ERROR_NOT_CAPABLE);
        }
        if ($fetchmode & DB_FETCHMODE_ASSOC) {
            if (function_exists('ibase_fetch_assoc')) {
                $arr = @ibase_fetch_assoc($result);
            } else {
                $arr = get_object_vars(ibase_fetch_object($result));
            }
            if ($this->options['portability'] & DB_PORTABILITY_LOWERCASE && $arr) {
                $arr = array_change_key_case($arr, CASE_LOWER);
            }
        } else {
            $arr = @ibase_fetch_row($result);
        }
        if (!$arr) {
            return null;
        }
        if ($this->options['portability'] & DB_PORTABILITY_RTRIM) {
            $this->_rtrimArrayValues($arr);
        }
        if ($this->options['portability'] & DB_PORTABILITY_NULL_TO_EMPTY) {
            $this->_convertNullArrayValuesToEmpty($arr);
        }
        return DB_OK;
    }

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

    /**
     * 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 $result is invalid
     *
     * @see DB_result::free()
     */
    public function freeResult($result)
    {
        return is_resource($result) ? ibase_free_result($result) : false;
    }

    // }}}
    // {{{ prepare()

    public function freeQuery($query)
    {
        return is_resource($query) ? ibase_free_query($query) : false;
    }

    // }}}
    // {{{ execute()

    /**
     * Determines the number of rows affected by a data maniuplation query
     *
     * 0 is returned for queries that don't manipulate data.
     *
     * @return int|object
     */
    public function affectedRows()
    {
        if (is_integer($this->affected)) {
            return $this->affected;
        }
        return $this->ibaseRaiseError(DB_ERROR_NOT_CAPABLE);
    }

    /**
     * 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 $result PHP's query result resource
     *
     * @return int|object
     *
     * @see DB_result::numCols()
     */
    public function numCols($result)
    {
        $cols = @ibase_num_fields($result);
        if (!$cols) {
            return $this->ibaseRaiseError();
        }
        return $cols;
    }

    // }}}
    // {{{ autoCommit()

    /**
     * Prepares a query for multiple execution with execute().
     *
     * prepare() requires a generic query as string like <code>
     *    INSERT INTO numbers VALUES (?, ?, ?)
     * </code>.  The <kbd>?</kbd> characters are placeholders.
     *
     * Three types of placeholders can be used:
     *   + <kbd>?</kbd>  a quoted scalar value, i.e. strings, integers
     *   + <kbd>!</kbd>  value is inserted 'as is'
     *   + <kbd>&</kbd>  requires a file name.  The file's contents get
     *                     inserted into the query (i.e. saving binary
     *                     data in a db)
     *
     * Use backslashes to escape placeholder characters if you don't want
     * them to be interpreted as placeholders.  Example: <code>
     *    "UPDATE foo SET col=? WHERE col='over \& under'"
     * </code>
     *
     * @param string $query query to be prepared
     * @return mixed DB statement resource on success. DB_Error on failure.
     */
    public function prepare($query)
    {
        $tokens = preg_split(
            '/((?<!\\\)[&?!])/',
            $query,
            -1,
            PREG_SPLIT_DELIM_CAPTURE
        );
        $token = 0;
        $types = array();
        $newquery = '';

        foreach ($tokens as $key => $val) {
            switch ($val) {
                case '?':
                    $types[$token++] = DB_PARAM_SCALAR;
                    break;
                case '&':
                    $types[$token++] = DB_PARAM_OPAQUE;
                    break;
                case '!':
                    $types[$token++] = DB_PARAM_MISC;
                    break;
                default:
                    $tokens[$key] = preg_replace('/\\\([&?!])/', "\\1", $val);
                    $newquery .= $tokens[$key] . '?';
            }
        }

        $newquery = substr($newquery, 0, -1);
        $this->last_query = $query;
        $newquery = $this->modifyQuery($newquery);
        $stmt = @ibase_prepare(/*$this->connection,*/ $newquery);

        if ($stmt === false) {
            $stmt = $this->ibaseRaiseError();
        } else {
            $this->prepare_types[(int)$stmt] = $types;
            $this->manip_query[(int)$stmt] = DB::isManip($query);
        }

        return $stmt;
    }

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

    /**
     * Executes a DB statement prepared with prepare().
     *
     * @param resource $stmt a DB statement resource returned from prepare()
     * @param mixed $data array, string or numeric data to be used in
     *                      execution of the statement.  Quantity of items
     *                      passed must match quantity of placeholders in
     *                      query:  meaning 1 for non-array items or the
     *                      quantity of elements in the array.
     * @return object  a new DB_Result or a DB_Error when fail
     * @see DB_ibase::prepare()
     * @access public
     */
    public function &execute($stmt, $data = array())
    {
        $data = (array)$data;
        $this->last_parameters = $data;

        $types = $this->prepare_types[(int)$stmt];
        if (count($types) != count($data)) {
            $tmp = $this->raiseError(DB_ERROR_MISMATCH);
            return $tmp;
        }

        $i = 0;
        foreach ($data as $key => $value) {
            if ($types[$i] == DB_PARAM_MISC) {
                /*
                 * ibase doesn't seem to have the ability to pass a
                 * parameter along unchanged, so strip off quotes from start
                 * and end, plus turn two single quotes to one single quote,
                 * in order to avoid the quotes getting escaped by
                 * ibase and ending up in the database.
                 */
                $data[$key] = preg_replace("/^'(.*)'$/", "\\1", $data[$key]);
                $data[$key] = str_replace("''", "'", $data[$key]);
            } elseif ($types[$i] == DB_PARAM_OPAQUE) {
                $fp = @fopen($data[$key], 'rb');
                if (!$fp) {
                    $tmp = $this->raiseError(DB_ERROR_ACCESS_VIOLATION);
                    return $tmp;
                }
                $data[$key] = fread($fp, filesize($data[$key]));
                fclose($fp);
            }
            $i++;
        }

        array_unshift($data, $stmt);

        $res = call_user_func_array('ibase_execute', $data);
        if (!$res) {
            $tmp = $this->ibaseRaiseError();
            return $tmp;
        }
        /* XXX need this?
        if ($this->autocommit && $this->manip_query[(int)$stmt]) {
            @ibase_commit($this->connection);
        }*/
        $this->last_stmt = $stmt;
        if ($this->manip_query[(int)$stmt] || $this->_next_query_manip) {
            $this->_last_query_manip = true;
            $this->_next_query_manip = false;
            $tmp = DB_OK;
        } else {
            $this->_last_query_manip = false;
            $tmp = new DB_result($this, $res);
        }
        return $tmp;
    }

    // }}}
    // {{{ rollback()

    /**
     * Frees the internal resources associated with a prepared query
     *
     * @param resource $stmt the prepared statement's PHP resource
     * @param bool $free_resource should the PHP resource be freed too?
     *                                  Use false if you need to get data
     *                                  from the result set later.
     *
     * @return bool  TRUE on success, FALSE if $result is invalid
     *
     * @see DB_ibase::prepare()
     */
    public function freePrepared($stmt, $free_resource = true)
    {
        if (!is_resource($stmt)) {
            return false;
        }
        if ($free_resource) {
            @ibase_free_query($stmt);
        }
        unset($this->prepare_tokens[(int)$stmt]);
        unset($this->prepare_types[(int)$stmt]);
        unset($this->manip_query[(int)$stmt]);
        return true;
    }

    // }}}
    // {{{ transactionInit()

    /**
     * Enables or disables automatic commits
     *
     * @param bool $onoff true turns it on, false turns it off
     *
     * @return int  DB_OK on success.  A DB_Error object if the driver
     *               doesn't support auto-committing transactions.
     */
    public function autoCommit($onoff = false)
    {
        $this->autocommit = $onoff ? 1 : 0;
        return DB_OK;
    }

    // }}}
    // {{{ nextId()

    /**
     * Commits the current transaction
     *
     * @return int  DB_OK on success.  A DB_Error object on failure.
     */
    public function commit()
    {
        return @ibase_commit($this->connection);
    }

    // }}}
    // {{{ createSequence()

    /**
     * Reverts the current transaction
     *
     * @return int  DB_OK on success.  A DB_Error object on failure.
     */
    public function rollback()
    {
        return @ibase_rollback($this->connection);
    }

    // }}}
    // {{{ dropSequence()

    public function transactionInit($trans_args = 0)
    {
        return $trans_args
            ? @ibase_trans($trans_args, $this->connection)
            : @ibase_trans();
    }

    // }}}
    // {{{ _ibaseFieldFlags()

    /**
     * Returns the next free id in a sequence
     *
     * @param string $seq_name name of the sequence
     * @param boolean $ondemand when true, the seqence is automatically
     *                            created if it does not exist
     *
     * @return int|object
     *               A DB_Error object on failure.
     *
     * @see DB_common::nextID(), DB_common::getSequenceName(),
     *      DB_ibase::createSequence(), DB_ibase::dropSequence()
     */
    public function nextId($seq_name, $ondemand = true)
    {
        $sqn = strtoupper($this->getSequenceName($seq_name));
        $repeat = 0;
        do {
            $this->pushErrorHandling(PEAR_ERROR_RETURN);
            $result = $this->query("SELECT GEN_ID(${sqn}, 1) "
                . 'FROM RDB$GENERATORS '
                . "WHERE RDB\$GENERATOR_NAME='${sqn}'");
            $this->popErrorHandling();
            if ($ondemand && DB::isError($result)) {
                $repeat = 1;
                $result = $this->createSequence($seq_name);
                if (DB::isError($result)) {
                    return $result;
                }
            } else {
                $repeat = 0;
            }
        } while ($repeat);
        if (DB::isError($result)) {
            return $this->raiseError($result);
        }
        $arr = $result->fetchRow(DB_FETCHMODE_ORDERED);
        $result->free();
        return $arr[0];
    }

    // }}}
    // {{{ ibaseRaiseError()

    /**
     * Creates a new sequence
     *
     * @param string $seq_name name of the new sequence
     *
     * @return int  DB_OK on success.  A DB_Error object on failure.
     *
     * @see DB_common::createSequence(), DB_common::getSequenceName(),
     *      DB_ibase::nextID(), DB_ibase::dropSequence()
     */
    public function createSequence($seq_name)
    {
        $sqn = strtoupper($this->getSequenceName($seq_name));
        $this->pushErrorHandling(PEAR_ERROR_RETURN);
        $result = $this->query("CREATE GENERATOR ${sqn}");
        $this->popErrorHandling();

        return $result;
    }

    // }}}
    // {{{ errorNative()

    /**
     * Deletes a sequence
     *
     * @param string $seq_name name of the sequence to be deleted
     *
     * @return int  DB_OK on success.  A DB_Error object on failure.
     *
     * @see DB_common::dropSequence(), DB_common::getSequenceName(),
     *      DB_ibase::nextID(), DB_ibase::createSequence()
     */
    public function dropSequence($seq_name)
    {
        return $this->query('DELETE FROM RDB$GENERATORS '
            . "WHERE RDB\$GENERATOR_NAME='"
            . strtoupper($this->getSequenceName($seq_name))
            . "'");
    }

    // }}}
    // {{{ errorCode()

    /**
     * Returns information about a table or a result set
     *
     * NOTE: only supports 'table' and 'flags' if <var>$result</var>
     * is a table name.
     *
     * @param object|string $result DB_result object from a query or a
     *                                 string containing the name of a table.
     *                                 While this also accepts a query result
     *                                 resource identifier, this behavior is
     *                                 deprecated.
     * @param int $mode a valid tableInfo mode
     *
     * @return array|object
     *                 A DB_Error object on failure.
     *
     * @see DB_common::tableInfo()
     */
    public function tableInfo($result, $mode = null)
    {
        if (is_string($result)) {
            /*
             * Probably received a table name.
             * Create a result resource identifier.
             */
            $id = @ibase_query(
                $this->connection,
                "SELECT * FROM $result WHERE 1=0"
            );
            $got_string = true;
        } elseif (isset($result->result)) {
            /*
             * Probably received a result object.
             * Extract the result resource identifier.
             */
            $id = $result->result;
            $got_string = false;
        } else {
            /*
             * Probably received a result resource identifier.
             * Copy it.
             * Deprecated.  Here for compatibility only.
             */
            $id = $result;
            $got_string = false;
        }

        if (!is_resource($id)) {
            return $this->ibaseRaiseError(DB_ERROR_NEED_MORE_DATA);
        }

        if ($this->options['portability'] & DB_PORTABILITY_LOWERCASE) {
            $case_func = 'strtolower';
        } else {
            $case_func = 'strval';
        }

        $count = @ibase_num_fields($id);
        $res = array();

        if ($mode) {
            $res['num_fields'] = $count;
        }

        for ($i = 0; $i < $count; $i++) {
            $info = @ibase_field_info($id, $i);
            $res[$i] = array(
                'table' => $got_string ? $case_func($result) : '',
                'name' => $case_func($info['name']),
                'type' => $info['type'],
                'len' => $info['length'],
                'flags' => ($got_string)
                    ? $this->_ibaseFieldFlags($info['name'], $result)
                    : '',
            );
            if ($mode & DB_TABLEINFO_ORDER) {
                $res['order'][$res[$i]['name']] = $i;
            }
            if ($mode & DB_TABLEINFO_ORDERTABLE) {
                $res['ordertable'][$res[$i]['table']][$res[$i]['name']] = $i;
            }
        }

        // free the result only if we were called on a table
        if ($got_string) {
            @ibase_free_result($id);
        }
        return $res;
    }

    // }}}
    // {{{ tableInfo()

    /**
     * Get the column's flags
     *
     * Supports "primary_key", "unique_key", "not_null", "default",
     * "computed" and "blob".
     *
     * @param string $field_name the name of the field
     * @param string $table_name the name of the table
     *
     * @return string  the flags
     *
     * @access private
     */
    public function _ibaseFieldFlags($field_name, $table_name)
    {
        $sql = 'SELECT R.RDB$CONSTRAINT_TYPE CTYPE'
            . ' FROM RDB$INDEX_SEGMENTS I'
            . '  JOIN RDB$RELATION_CONSTRAINTS R ON I.RDB$INDEX_NAME=R.RDB$INDEX_NAME'
            . ' WHERE I.RDB$FIELD_NAME=\'' . $field_name . '\''
            . '  AND UPPER(R.RDB$RELATION_NAME)=\'' . strtoupper($table_name) . '\'';

        $result = @ibase_query($this->connection, $sql);
        if (!$result) {
            return $this->ibaseRaiseError();
        }

        $flags = '';
        if ($obj = @ibase_fetch_object($result)) {
            @ibase_free_result($result);
            if (isset($obj->CTYPE) && trim($obj->CTYPE) == 'PRIMARY KEY') {
                $flags .= 'primary_key ';
            }
            if (isset($obj->CTYPE) && trim($obj->CTYPE) == 'UNIQUE') {
                $flags .= 'unique_key ';
            }
        }

        $sql = 'SELECT R.RDB$NULL_FLAG AS NFLAG,'
            . '  R.RDB$DEFAULT_SOURCE AS DSOURCE,'
            . '  F.RDB$FIELD_TYPE AS FTYPE,'
            . '  F.RDB$COMPUTED_SOURCE AS CSOURCE'
            . ' FROM RDB$RELATION_FIELDS R '
            . '  JOIN RDB$FIELDS F ON R.RDB$FIELD_SOURCE=F.RDB$FIELD_NAME'
            . ' WHERE UPPER(R.RDB$RELATION_NAME)=\'' . strtoupper($table_name) . '\''
            . '  AND R.RDB$FIELD_NAME=\'' . $field_name . '\'';

        $result = @ibase_query($this->connection, $sql);
        if (!$result) {
            return $this->ibaseRaiseError();
        }
        if ($obj = @ibase_fetch_object($result)) {
            @ibase_free_result($result);
            if (isset($obj->NFLAG)) {
                $flags .= 'not_null ';
            }
            if (isset($obj->DSOURCE)) {
                $flags .= 'default ';
            }
            if (isset($obj->CSOURCE)) {
                $flags .= 'computed ';
            }
            if (isset($obj->FTYPE) && $obj->FTYPE == 261) {
                $flags .= 'blob ';
            }
        }

        return trim($flags);
    }

    // }}}
    // {{{ getSpecialQuery()

    /**
     * Obtains the query string needed for listing a given type of objects
     *
     * @param string $type the kind of objects you want to retrieve
     *
     * @return string  the SQL query string or null if the driver doesn't
     *                  support the object type requested
     *
     * @access protected
     * @see DB_common::getListOf()
     */
    public function getSpecialQuery($type)
    {
        switch ($type) {
            case 'tables':
                return 'SELECT DISTINCT R.RDB$RELATION_NAME FROM '
                    . 'RDB$RELATION_FIELDS R WHERE R.RDB$SYSTEM_FLAG=0';
            case 'views':
                return 'SELECT DISTINCT RDB$VIEW_NAME from RDB$VIEW_RELATIONS';
            case 'users':
                return 'SELECT DISTINCT RDB$USER FROM RDB$USER_PRIVILEGES';
            default:
                return null;
        }
    }

    // }}}
}

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 */