mssql_driver.php

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<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package             CodeIgniter
 * @author              ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2006, EllisLab, Inc.
 * @license             http://codeigniter.com/user_guide/license.html
 * @link                http://codeigniter.com
 * @since               Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * MS SQL Database Adapter Class
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the active record
 * class is being used or not.
 *
 * @package             CodeIgniter
 * @subpackage  Drivers
 * @category    Database
 * @author              ExpressionEngine Dev Team
 * @link                http://codeigniter.com/user_guide/database/
 */
class CI_DB_mssql_driver extends CI_DB {

        /**
         * The syntax to count rows is slightly different across different
         * database engines, so this string appears in each driver and is
         * used for the count_all() and count_all_results() functions.
         */
        var $_count_string = "SELECT COUNT(*) AS ";
        var $_random_keyword = ' ASC'; // not currently supported
        
        /**
         * Non-persistent database connection
         *
         * @access      private called by the base class
         * @return      resource
         */     
        function db_connect()
        {
                return @mssql_connect($this->hostname, $this->username, $this->password);
        }
        
        // --------------------------------------------------------------------

        /**
         * Persistent database connection
         *
         * @access      private called by the base class
         * @return      resource
         */     
        function db_pconnect()
        {
                return @mssql_pconnect($this->hostname, $this->username, $this->password);
        }
        
        // --------------------------------------------------------------------

        /**
         * Select the database
         *
         * @access      private called by the base class
         * @return      resource
         */     
        function db_select()
        {
                return @mssql_select_db($this->database, $this->conn_id);
        }

        // --------------------------------------------------------------------
        
        /**
         * Set client character set
         *
         * @access      public
         * @param       string
         * @param       string
         * @return      resource
         */
        function db_set_charset($charset, $collation)
        {
                // TODO - add support if needed
                return TRUE;
        }

        // --------------------------------------------------------------------
        
        /**
         * Execute the query
         *
         * @access      private called by the base class
         * @param       string  an SQL query
         * @return      resource
         */     
        function _execute($sql)
        {
                $sql = $this->_prep_query($sql);
                return @mssql_query($sql, $this->conn_id);
        }
        
        // --------------------------------------------------------------------

        /**
         * Prep the query
         *
         * If needed, each database adapter can prep the query string
         *
         * @access      private called by execute()
         * @param       string  an SQL query
         * @return      string
         */     
        function _prep_query($sql)
        {
                return $sql;
        }

        // --------------------------------------------------------------------

        /**
         * Begin Transaction
         *
         * @access      public
         * @return      bool            
         */     
        function trans_begin($test_mode = FALSE)
        {
                if ( ! $this->trans_enabled)
                {
                        return TRUE;
                }
                
                // When transactions are nested we only begin/commit/rollback the outermost ones
                if ($this->_trans_depth > 0)
                {
                        return TRUE;
                }

                // Reset the transaction failure flag.
                // If the $test_mode flag is set to TRUE transactions will be rolled back
                // even if the queries produce a successful result.
                $this->_trans_failure = ($test_mode === TRUE) ? TRUE : FALSE;

                $this->simple_query('BEGIN TRAN');
                return TRUE;
        }

        // --------------------------------------------------------------------

        /**
         * Commit Transaction
         *
         * @access      public
         * @return      bool            
         */     
        function trans_commit()
        {
                if ( ! $this->trans_enabled)
                {
                        return TRUE;
                }

                // When transactions are nested we only begin/commit/rollback the outermost ones
                if ($this->_trans_depth > 0)
                {
                        return TRUE;
                }

                $this->simple_query('COMMIT TRAN');
                return TRUE;
        }

        // --------------------------------------------------------------------

        /**
         * Rollback Transaction
         *
         * @access      public
         * @return      bool            
         */     
        function trans_rollback()
        {
                if ( ! $this->trans_enabled)
                {
                        return TRUE;
                }

                // When transactions are nested we only begin/commit/rollback the outermost ones
                if ($this->_trans_depth > 0)
                {
                        return TRUE;
                }

                $this->simple_query('ROLLBACK TRAN');
                return TRUE;
        }
        
        // --------------------------------------------------------------------

        /**
         * Escape String
         *
         * @access      public
         * @param       string
         * @return      string
         */
        function escape_str($str)       
        {       
                // Escape single quotes
                return str_replace("'", "''", $str);
        }
        
        // --------------------------------------------------------------------

        /**
         * Affected Rows
         *
         * @access      public
         * @return      integer
         */
        function affected_rows()
        {
                return @mssql_rows_affected($this->conn_id);
        }
        
        // --------------------------------------------------------------------

        /**
        * Insert ID
        *
        * Returns the last id created in the Identity column.
        *
        * @access public
        * @return integer
        */
        function insert_id()
        {
                $ver = self::_parse_major_version($this->version());
                $sql = ($ver >= 8 ? "SELECT SCOPE_IDENTITY() AS last_id" : "SELECT @@IDENTITY AS last_id");
                $query = $this->query($sql);
                $row = $query->row();
                return $row->last_id;
        }

        // --------------------------------------------------------------------

        /**
        * Parse major version
        *
        * Grabs the major version number from the 
        * database server version string passed in.
        *
        * @access private
        * @param string $version
        * @return int16 major version number
        */
        function _parse_major_version($version)
        {
                preg_match('/([0-9]+)\.([0-9]+)\.([0-9]+)/', $version, $ver_info);
                return $ver_info[1]; // return the major version b/c that's all we're interested in.
        }

        // --------------------------------------------------------------------

        /**
        * Version number query string
        *
        * @access public
        * @return string
        */
        function _version()
        {
                return "SELECT @@VERSION AS ver";
        }

        // --------------------------------------------------------------------

        /**
         * "Count All" query
         *
         * Generates a platform-specific query string that counts all records in
         * the specified database
         *
         * @access      public
         * @param       string
         * @return      string
         */
        function count_all($table = '')
        {
                if ($table == '')
                        return '0';
        
                $query = $this->query($this->_count_string . $this->_protect_identifiers('numrows'). " FROM " . $this->_protect_identifiers($this->dbprefix.$table));

                if ($query->num_rows() == 0)
                        return '0';

                $row = $query->row();
                return $row->numrows;
        }

        // --------------------------------------------------------------------

        /**
         * List table query
         *
         * Generates a platform-specific query string so that the table names can be fetched
         *
         * @access      private
         * @param       boolean
         * @return      string
         */
        function _list_tables($prefix_limit = FALSE)
        {
                $sql = "SELECT name FROM sysobjects WHERE type = 'U' ORDER BY name";
                
                // for future compatibility
                if ($prefix_limit !== FALSE AND $this->dbprefix != '')
                {
                        //$sql .= " LIKE '".$this->dbprefix."%'";
                        return FALSE; // not currently supported
                }
                
                return $sql;
        }

        // --------------------------------------------------------------------

        /**
         * List column query
         *
         * Generates a platform-specific query string so that the column names can be fetched
         *
         * @access      private
         * @param       string  the table name
         * @return      string
         */
        function _list_columns($table = '')
        {
                return "SELECT * FROM INFORMATION_SCHEMA.Columns WHERE TABLE_NAME = '".$this->_escape_table($table)."'";        
        }

        // --------------------------------------------------------------------

        /**
         * Field data query
         *
         * Generates a platform-specific query so that the column data can be retrieved
         *
         * @access      public
         * @param       string  the table name
         * @return      object
         */
        function _field_data($table)
        {
                return "SELECT TOP 1 * FROM ".$this->_escape_table($table);     
        }

        // --------------------------------------------------------------------

        /**
         * The error message string
         *
         * @access      private
         * @return      string
         */
        function _error_message()
        {
                // Are errros even supported in MS SQL?
                return '';
        }
        
        // --------------------------------------------------------------------

        /**
         * The error message number
         *
         * @access      private
         * @return      integer
         */
        function _error_number()
        {
                // Are error numbers supported?
                return '';
        }
        
        // --------------------------------------------------------------------

        /**
         * Escape Table Name
         *
         * This function adds backticks if the table name has a period
         * in it. Some DBs will get cranky unless periods are escaped
         *
         * @access      private
         * @param       string  the table name
         * @return      string
         */
        function _escape_table($table)
        {
                // I don't believe this is necessary with MS SQL.  Not sure, though. - Rick
        
                /*
                if (strpos($table, '.') !== FALSE)
                {
                        $table = '"' . str_replace('.', '"."', $table) . '"';
                }
                */
                
                return $table;
        }       
        
        // --------------------------------------------------------------------

        /**
         * Protect Identifiers
         *
         * This function adds backticks if appropriate based on db type
         *
         * @access      private
         * @param       mixed   the item(s)
         * @param       boolean should spaces be backticked
         * @param       boolean only affect the first word
         * @return      mixed   the item with backticks
         */     
        function _protect_identifiers($item, $first_word_only = FALSE)
        {
                if (is_array($item))
                {
                        $escaped_array = array();

                        foreach($item as $k=>$v)
                        {
                                $escaped_array[$this->_protect_identifiers($k)] = $this->_protect_identifiers($v, $first_word_only);
                        }

                        return $escaped_array;
                }       

                // This function may get "item1 item2" as a string, and so
                // we may need ""item1" "item2"" and not ""item1 item2""
                if (ctype_alnum($item) === FALSE)
                {
                        if (strpos($item, '.') !== FALSE)
                        {
                                $aliased_tables = implode(".",$this->ar_aliased_tables).'.';
                                $table_name =  substr($item, 0, strpos($item, '.')+1);
                                $item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;
                        }

                        // This function may get "field >= 1", and need it to return ""field" >= 1"
                        $lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

                        $item = preg_replace('/(^'.$lbound.')([\w\d\-\_]+?)(\s|\)|$)/iS', '$1"$2"$3', $item);
                }
                else
                {
                        return "\"{$item}\"";
                }

                $exceptions = array('AS', '/', '-', '%', '+', '*', 'OR', 'IS');
                
                foreach ($exceptions as $exception)
                {
                
                        if (stristr($item, " \"{$exception}\" ") !== FALSE)
                        {
                                $item = preg_replace('/ "('.preg_quote($exception).')" /i', ' $1 ', $item);
                        }
                }
                return $item;
        }
                        
        // --------------------------------------------------------------------

        /**
         * From Tables
         *
         * This function implicitly groups FROM tables so there is no confusion
         * about operator precedence in harmony with SQL standards
         *
         * @access      public
         * @param       type
         * @return      type
         */
        function _from_tables($tables)
        {
                if ( ! is_array($tables))
                {
                        $tables = array($tables);
                }
                
                return implode(', ', $tables);
        }

        // --------------------------------------------------------------------
        
        /**
         * Insert statement
         *
         * Generates a platform-specific insert string from the supplied data
         *
         * @access      public
         * @param       string  the table name
         * @param       array   the insert keys
         * @param       array   the insert values
         * @return      string
         */
        function _insert($table, $keys, $values)
        {       
                return "INSERT INTO ".$this->_escape_table($table)." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
        }
        
        // --------------------------------------------------------------------

        /**
         * Update statement
         *
         * Generates a platform-specific update string from the supplied data
         *
         * @access      public
         * @param       string  the table name
         * @param       array   the update data
         * @param       array   the where clause
         * @param       array   the orderby clause
         * @param       array   the limit clause
         * @return      string
         */
        function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
        {
                foreach($values as $key => $val)
                {
                        $valstr[] = $key." = ".$val;
                }
                
                $limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
                
                $orderby = (count($orderby) >= 1)?' ORDER BY '.implode(", ", $orderby):'';
        
                $sql = "UPDATE ".$this->_escape_table($table)." SET ".implode(', ', $valstr);
                $sql .= ($where != '' AND count($where) >=1) ? " WHERE ".implode(" ", $where) : '';
                $sql .= $orderby.$limit;
                
                return $sql;
        }

        
        // --------------------------------------------------------------------

        /**
         * Truncate statement
         *
         * Generates a platform-specific truncate string from the supplied data
         * If the database does not support the truncate() command
         * This function maps to "DELETE FROM table"
         *
         * @access      public
         * @param       string  the table name
         * @return      string
         */     
        function _truncate($table)
        {
                return "TRUNCATE ".$this->_escape_table($table);
        }
        
        // --------------------------------------------------------------------

        /**
         * Delete statement
         *
         * Generates a platform-specific delete string from the supplied data
         *
         * @access      public
         * @param       string  the table name
         * @param       array   the where clause
         * @param       string  the limit clause
         * @return      string
         */     
        function _delete($table, $where = array(), $like = array(), $limit = FALSE)
        {
                $conditions = '';

                if (count($where) > 0 OR count($like) > 0)
                {
                        $conditions = "\nWHERE ";
                        $conditions .= implode("\n", $this->ar_where);

                        if (count($where) > 0 && count($like) > 0)
                        {
                                $conditions .= " AND ";
                        }
                        $conditions .= implode("\n", $like);
                }

                $limit = ( ! $limit) ? '' : ' LIMIT '.$limit;
        
                return "DELETE FROM ".$table.$conditions.$limit;
        }

        // --------------------------------------------------------------------

        /**
         * Limit string
         *
         * Generates a platform-specific LIMIT clause
         *
         * @access      public
         * @param       string  the sql query string
         * @param       integer the number of rows to limit the query to
         * @param       integer the offset value
         * @return      string
         */
        function _limit($sql, $limit, $offset)
        {
                $i = $limit + $offset;
        
                return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$i.' ', $sql);               
        }

        // --------------------------------------------------------------------

        /**
         * Close DB Connection
         *
         * @access      public
         * @param       resource
         * @return      void
         */
        function _close($conn_id)
        {
                @mssql_close($conn_id);
        }       

}



/* End of file mssql_driver.php */
/* Location: ./system/database/drivers/mssql/mssql_driver.php */