gnu-social/extlib/DB/mssql.php

<?php

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

/**
 * The PEAR DB driver for PHP's mssql extension
 * for interacting with Microsoft SQL Server 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     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 mssql extension
 * for interacting with Microsoft SQL Server databases
 *
 * These methods overload the ones declared in DB_common.
 *
 * DB's mssql driver is only for Microsfoft SQL Server databases.
 *
 * If you're connecting to a Sybase database, you MUST specify "sybase"
 * as the "phptype" in the DSN.
 *
 * This class only works correctly if you have compiled PHP using
 * --with-mssql=[dir_to_FreeTDS].
 *
 * @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
 */
class DB_mssql extends DB_common
{
    // {{{ properties

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

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

    /**
     * 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
     */
    public $features = array(
        'limit' => 'emulate',
        'new_link' => false,
        'numrows' => true,
        'pconnect' => true,
        'prepare' => false,
        'ssl' => false,
        'transactions' => true,
    );

    /**
     * A mapping of native error codes to DB error codes
     * @var array
     */
    // XXX Add here error codes ie: 'S100E' => DB_ERROR_SYNTAX
    public $errorcode_map = array(
        102 => DB_ERROR_SYNTAX,
        110 => DB_ERROR_VALUE_COUNT_ON_ROW,
        155 => DB_ERROR_NOSUCHFIELD,
        156 => DB_ERROR_SYNTAX,
        170 => DB_ERROR_SYNTAX,
        207 => DB_ERROR_NOSUCHFIELD,
        208 => DB_ERROR_NOSUCHTABLE,
        245 => DB_ERROR_INVALID_NUMBER,
        319 => DB_ERROR_SYNTAX,
        321 => DB_ERROR_NOSUCHFIELD,
        325 => DB_ERROR_SYNTAX,
        336 => DB_ERROR_SYNTAX,
        515 => DB_ERROR_CONSTRAINT_NOT_NULL,
        547 => DB_ERROR_CONSTRAINT,
        1018 => DB_ERROR_SYNTAX,
        1035 => DB_ERROR_SYNTAX,
        1913 => DB_ERROR_ALREADY_EXISTS,
        2209 => DB_ERROR_SYNTAX,
        2223 => DB_ERROR_SYNTAX,
        2248 => DB_ERROR_SYNTAX,
        2256 => DB_ERROR_SYNTAX,
        2257 => DB_ERROR_SYNTAX,
        2627 => DB_ERROR_CONSTRAINT,
        2714 => DB_ERROR_ALREADY_EXISTS,
        3607 => DB_ERROR_DIVZERO,
        3701 => DB_ERROR_NOSUCHTABLE,
        7630 => DB_ERROR_SYNTAX,
        8134 => DB_ERROR_DIVZERO,
        9303 => DB_ERROR_SYNTAX,
        9317 => DB_ERROR_SYNTAX,
        9318 => DB_ERROR_SYNTAX,
        9331 => DB_ERROR_SYNTAX,
        9332 => DB_ERROR_SYNTAX,
        15253 => DB_ERROR_SYNTAX,
    );

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

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


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

    /**
     * The quantity of transactions begun
     *
     * {@internal  While this is private, it can't actually be designated
     * private in PHP 5 because it is directly accessed in the test suite.}}
     *
     * @var integer
     * @access private
     */
    public $transaction_opcount = 0;

    /**
     * The database specified in the DSN
     *
     * It's a fix to allow calls to different databases in the same script.
     *
     * @var string
     * @access private
     */
    public $_db = null;


    // }}}
    // {{{ 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.
     *
     * @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('mssql') && !PEAR::loadExtension('sybase')
            && !PEAR::loadExtension('sybase_ct')) {
            return $this->raiseError(DB_ERROR_EXTENSION_NOT_FOUND);
        }

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

        $params = array(
            $dsn['hostspec'] ? $dsn['hostspec'] : 'localhost',
            $dsn['username'] ? $dsn['username'] : null,
            $dsn['password'] ? $dsn['password'] : null,
        );
        if ($dsn['port']) {
            $params[0] .= ((substr(PHP_OS, 0, 3) == 'WIN') ? ',' : ':')
                . $dsn['port'];
        }

        $connect_function = $persistent ? 'mssql_pconnect' : 'mssql_connect';

        $this->connection = @call_user_func_array($connect_function, $params);

        if (!$this->connection) {
            return $this->raiseError(
                DB_ERROR_CONNECT_FAILED,
                null,
                null,
                null,
                @mssql_get_last_message()
            );
        }
        if ($dsn['database']) {
            if (!@mssql_select_db($dsn['database'], $this->connection)) {
                return $this->raiseError(
                    DB_ERROR_NODBSELECTED,
                    null,
                    null,
                    null,
                    @mssql_get_last_message()
                );
            }
            $this->_db = $dsn['database'];
        }
        return DB_OK;
    }

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

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

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

    /**
     * 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 = $query;
        if (!@mssql_select_db($this->_db, $this->connection)) {
            return $this->mssqlRaiseError(DB_ERROR_NODBSELECTED);
        }
        $query = $this->modifyQuery($query);
        if (!$this->autocommit && $ismanip) {
            if ($this->transaction_opcount == 0) {
                $result = @mssql_query('BEGIN TRAN', $this->connection);
                if (!$result) {
                    return $this->mssqlRaiseError();
                }
            }
            $this->transaction_opcount++;
        }
        $result = @mssql_query($query, $this->connection);
        if (!$result) {
            return $this->mssqlRaiseError();
        }
        // Determine which queries that should return data, and which
        // should return an error code only.
        return $ismanip ? DB_OK : $result;
    }

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

    /**
     * Produces a DB_Error object regarding the current problem
     *
     * @param null $code
     * @return object  the DB_Error object
     *
     * @see DB_common::raiseError(),
     *      DB_mssql::errorNative(), DB_mssql::errorCode()
     */
    public function mssqlRaiseError($code = null)
    {
        $message = @mssql_get_last_message();
        if (!$code) {
            $code = $this->errorNative();
        }
        return $this->raiseError(
            $this->errorCode($code, $message),
            null,
            null,
            null,
            "$code - $message"
        );
    }

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

    /**
     * Gets the DBMS' native error code produced by the last query
     *
     * @return int  the DBMS' error code
     */
    public function errorNative()
    {
        $res = @mssql_query('select @@ERROR as ErrorCode', $this->connection);
        if (!$res) {
            return DB_ERROR;
        }
        $row = @mssql_fetch_row($res);
        return $row[0];
    }

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

    /**
     * Determines PEAR::DB error code from mssql's native codes.
     *
     * If <var>$nativecode</var> isn't known yet, it will be looked up.
     *
     * @param mixed $nativecode mssql error code, if known
     * @param string $msg
     * @return integer  an error number from a DB error constant
     * @see errorNative()
     */
    public function errorCode($nativecode = null, $msg = '')
    {
        if (!$nativecode) {
            $nativecode = $this->errorNative();
        }
        if (isset($this->errorcode_map[$nativecode])) {
            if ($nativecode == 3701
                && preg_match('/Cannot drop the index/i', $msg)) {
                return DB_ERROR_NOT_FOUND;
            }
            return $this->errorcode_map[$nativecode];
        } else {
            return DB_ERROR;
        }
    }

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

    /**
     * Move the internal mssql 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($result)
    {
        return @mssql_next_result($result);
    }

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

    /**
     * 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) {
            if (!@mssql_data_seek($result, $rownum)) {
                return null;
            }
        }
        if ($fetchmode & DB_FETCHMODE_ASSOC) {
            $arr = @mssql_fetch_assoc($result);
            if ($this->options['portability'] & DB_PORTABILITY_LOWERCASE && $arr) {
                $arr = array_change_key_case($arr, CASE_LOWER);
            }
        } else {
            $arr = @mssql_fetch_row($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;
    }

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

    /**
     * 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($result) ? mssql_free_result($result) : false;
    }

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

    /**
     * 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)
    {
        $cols = @mssql_num_fields($result);
        if (!$cols) {
            return $this->mssqlRaiseError();
        }
        return $cols;
    }

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

    /**
     * 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 $result PHP's query result resource
     *
     * @return int|object
     *
     * @see DB_result::numRows()
     */
    public function numRows($result)
    {
        $rows = @mssql_num_rows($result);
        if ($rows === false) {
            return $this->mssqlRaiseError();
        }
        return $rows;
    }

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

    /**
     * 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)
    {
        // XXX if $this->transaction_opcount > 0, we should probably
        // issue a warning here.
        $this->autocommit = $onoff ? true : false;
        return DB_OK;
    }

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

    /**
     * Commits the current transaction
     *
     * @return int|object
     */
    public function commit()
    {
        if ($this->transaction_opcount > 0) {
            if (!@mssql_select_db($this->_db, $this->connection)) {
                return $this->mssqlRaiseError(DB_ERROR_NODBSELECTED);
            }
            $result = @mssql_query('COMMIT TRAN', $this->connection);
            $this->transaction_opcount = 0;
            if (!$result) {
                return $this->mssqlRaiseError();
            }
        }
        return DB_OK;
    }

    /**
     * Reverts the current transaction
     *
     * @return int|object
     */
    public function rollback()
    {
        if ($this->transaction_opcount > 0) {
            if (!@mssql_select_db($this->_db, $this->connection)) {
                return $this->mssqlRaiseError(DB_ERROR_NODBSELECTED);
            }
            $result = @mssql_query('ROLLBACK TRAN', $this->connection);
            $this->transaction_opcount = 0;
            if (!$result) {
                return $this->mssqlRaiseError();
            }
        }
        return DB_OK;
    }

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

    /**
     * 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 ($this->_last_query_manip) {
            $res = @mssql_query('select @@rowcount', $this->connection);
            if (!$res) {
                return $this->mssqlRaiseError();
            }
            $ar = @mssql_fetch_row($res);
            if (!$ar) {
                $result = 0;
            } else {
                @mssql_free_result($res);
                $result = $ar[0];
            }
        } else {
            $result = 0;
        }
        return $result;
    }

    // }}}
    // {{{ escapeSimple()

    /**
     * Returns the next free id in a sequence
     *
     * @param string $seq_name name of the sequence
     * @param boolean $ondemand when true, the seqence is automatically
     *                            created if it does not exist
     *
     * @return int|object
     *               A DB_Error object on failure.
     *
     * @see DB_common::nextID(), DB_common::getSequenceName(),
     *      DB_mssql::createSequence(), DB_mssql::dropSequence()
     */
    public function nextId($seq_name, $ondemand = true)
    {
        $seqname = $this->getSequenceName($seq_name);
        if (!@mssql_select_db($this->_db, $this->connection)) {
            return $this->mssqlRaiseError(DB_ERROR_NODBSELECTED);
        }
        $repeat = 0;
        do {
            $this->pushErrorHandling(PEAR_ERROR_RETURN);
            $result = $this->query("INSERT INTO $seqname (vapor) VALUES (0)");
            $this->popErrorHandling();
            if ($ondemand && DB::isError($result) &&
                ($result->getCode() == DB_ERROR || $result->getCode() == DB_ERROR_NOSUCHTABLE)) {
                $repeat = 1;
                $result = $this->createSequence($seq_name);
                if (DB::isError($result)) {
                    return $this->raiseError($result);
                }
            } elseif (!DB::isError($result)) {
                $result = $this->query("SELECT IDENT_CURRENT('$seqname')");
                if (DB::isError($result)) {
                    /* Fallback code for MS SQL Server 7.0, which doesn't have
                     * IDENT_CURRENT. This is *not* safe for concurrent
                     * requests, and really, if you're using it, you're in a
                     * world of hurt. Nevertheless, it's here to ensure BC. See
                     * bug #181 for the gory details.*/
                    $result = $this->query("SELECT @@IDENTITY FROM $seqname");
                }
                $repeat = 0;
            } else {
                $repeat = false;
            }
        } while ($repeat);
        if (DB::isError($result)) {
            return $this->raiseError($result);
        }
        $result = $result->fetchRow(DB_FETCHMODE_ORDERED);
        return $result[0];
    }

    // }}}
    // {{{ quoteIdentifier()

    /**
     * Creates a new sequence
     *
     * @param string $seq_name name of the new sequence
     *
     * @return int  DB_OK on success.  A DB_Error object on failure.
     *
     * @see DB_common::createSequence(), DB_common::getSequenceName(),
     *      DB_mssql::nextID(), DB_mssql::dropSequence()
     */
    public function createSequence($seq_name)
    {
        return $this->query('CREATE TABLE '
            . $this->getSequenceName($seq_name)
            . ' ([id] [int] IDENTITY (1, 1) NOT NULL,'
            . ' [vapor] [int] NULL)');
    }

    // }}}
    // {{{ mssqlRaiseError()

    /**
     * Deletes a sequence
     *
     * @param string $seq_name name of the sequence to be deleted
     *
     * @return int  DB_OK on success.  A DB_Error object on failure.
     *
     * @see DB_common::dropSequence(), DB_common::getSequenceName(),
     *      DB_mssql::nextID(), DB_mssql::createSequence()
     */
    public function dropSequence($seq_name)
    {
        return $this->query('DROP TABLE ' . $this->getSequenceName($seq_name));
    }

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

    /**
     * Escapes a string in a manner suitable for SQL Server.
     *
     * @param string $str the string to be escaped
     * @return string  the escaped string
     *
     * @see DB_common::quoteSmart()
     * @since Method available since Release 1.6.0
     */
    public function escapeSimple($str)
    {
        return str_replace(
            array("'", "\\\r\n", "\\\n"),
            array("''", "\\\\\r\n\r\n", "\\\\\n\n"),
            $str
        );
    }

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

    /**
     * Quotes a string so it can be safely used as a table or column name
     *
     * @param string $str identifier name to be quoted
     *
     * @return string  quoted identifier string
     *
     * @see DB_common::quoteIdentifier()
     * @since Method available since Release 1.6.0
     */
    public function quoteIdentifier($str)
    {
        return '[' . str_replace(']', ']]', $str) . ']';
    }

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

    /**
     * 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.
             */
            if (!@mssql_select_db($this->_db, $this->connection)) {
                return $this->mssqlRaiseError(DB_ERROR_NODBSELECTED);
            }
            $id = @mssql_query(
                "SELECT * FROM $result WHERE 1=0",
                $this->connection
            );
            $got_string = true;
        } elseif (isset($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->mssqlRaiseError(DB_ERROR_NEED_MORE_DATA);
        }

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

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

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

        for ($i = 0; $i < $count; $i++) {
            if ($got_string) {
                $flags = $this->_mssql_field_flags(
                    $result,
                    @mssql_field_name($id, $i)
                );
                if (DB::isError($flags)) {
                    return $flags;
                }
            } else {
                $flags = '';
            }

            $res[$i] = array(
                'table' => $got_string ? $case_func($result) : '',
                'name' => $case_func(@mssql_field_name($id, $i)),
                'type' => @mssql_field_type($id, $i),
                'len' => @mssql_field_length($id, $i),
                '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;
            }
        }

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

    // }}}
    // {{{ _mssql_field_flags()

    /**
     * Get a column's flags
     *
     * Supports "not_null", "primary_key",
     * "auto_increment" (mssql identity), "timestamp" (mssql timestamp),
     * "unique_key" (mssql unique index, unique check or primary_key) and
     * "multiple_key" (multikey index)
     *
     * mssql timestamp is NOT similar to the mysql timestamp so this is maybe
     * not useful at all - is the behaviour of mysql_field_flags that primary
     * keys are alway unique? is the interpretation of multiple_key correct?
     *
     * @param string $table the table name
     * @param string $column the field name
     *
     * @return array|string
     *
     * @access private
     * @author Joern Barthel <j_barthel@web.de>
     */
    public function _mssql_field_flags($table, $column)
    {
        static $tableName = null;
        static $flags = array();

        if ($table != $tableName) {
            $flags = array();
            $tableName = $table;

            // get unique and primary keys
            $res = $this->getAll("EXEC SP_HELPINDEX $table", DB_FETCHMODE_ASSOC);
            if (DB::isError($res)) {
                return $res;
            }

            foreach ($res as $val) {
                $keys = explode(', ', $val['index_keys']);

                if (sizeof($keys) > 1) {
                    foreach ($keys as $key) {
                        $this->_add_flag($flags[$key], 'multiple_key');
                    }
                }

                if (strpos($val['index_description'], 'primary key')) {
                    foreach ($keys as $key) {
                        $this->_add_flag($flags[$key], 'primary_key');
                    }
                } elseif (strpos($val['index_description'], 'unique')) {
                    foreach ($keys as $key) {
                        $this->_add_flag($flags[$key], 'unique_key');
                    }
                }
            }

            // get auto_increment, not_null and timestamp
            $res = $this->getAll("EXEC SP_COLUMNS $table", DB_FETCHMODE_ASSOC);
            if (DB::isError($res)) {
                return $res;
            }

            foreach ($res as $val) {
                $val = array_change_key_case($val, CASE_LOWER);
                if ($val['nullable'] == '0') {
                    $this->_add_flag($flags[$val['column_name']], 'not_null');
                }
                if (strpos($val['type_name'], 'identity')) {
                    $this->_add_flag($flags[$val['column_name']], 'auto_increment');
                }
                if (strpos($val['type_name'], 'timestamp')) {
                    $this->_add_flag($flags[$val['column_name']], 'timestamp');
                }
            }
        }

        if (array_key_exists($column, $flags)) {
            return (implode(' ', $flags[$column]));
        }
        return '';
    }

    // }}}
    // {{{ _add_flag()

    /**
     * Adds a string to the flags array if the flag is not yet in there
     * - if there is no flag present the array is created
     *
     * @param array  &$array the reference to the flag-array
     * @param string $value the flag value
     *
     * @return void
     *
     * @access private
     * @author Joern Barthel <j_barthel@web.de>
     */
    public function _add_flag(&$array, $value)
    {
        if (!is_array($array)) {
            $array = array($value);
        } elseif (!in_array($value, $array)) {
            array_push($array, $value);
        }
    }

    // }}}
    // {{{ 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 name FROM sysobjects WHERE type = 'U'"
                    . ' ORDER BY name';
            case 'views':
                return "SELECT name FROM sysobjects WHERE type = 'V'";
            default:
                return null;
        }
    }

    // }}}
}

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