mysql_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) 2008, EllisLab, Inc.
 * @license             http://codeigniter.com/user_guide/license.html
 * @link                http://codeigniter.com
 * @since               Version 1.0
 * @filesource
 */

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

/**
 * MySQL 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_mysql_driver extends CI_DB {

        var $dbdriver = 'mysql';

        // The character used for escaping
        var     $_escape_char = '`';
        
        /**
         * Whether to use the MySQL "delete hack" which allows the number
         * of affected rows to be shown. Uses a preg_replace when enabled,
         * adding a bit more processing to all queries.
         */     
        var $delete_hack = TRUE;
        
        /**
         * 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 = ' RAND()'; // database specific random keyword

        /**
         * Non-persistent database connection
         *
         * @access      private called by the base class
         * @return      resource
         */     
        function db_connect()
        {
                if ($this->port != '')
                {
                        $this->hostname .= ':'.$this->port;
                }
                
                return @mysql_connect($this->hostname, $this->username, $this->password, TRUE);
        }
        
        // --------------------------------------------------------------------

        /**
         * Persistent database connection
         *
         * @access      private called by the base class
         * @return      resource
         */     
        function db_pconnect()
        {
                if ($this->port != '')
                {
                        $this->hostname .= ':'.$this->port;
                }

                return @mysql_pconnect($this->hostname, $this->username, $this->password);
        }
        
        // --------------------------------------------------------------------

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

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

        /**
         * Set client character set
         *
         * @access      public
         * @param       string
         * @param       string
         * @return      resource
         */
        function db_set_charset($charset, $collation)
        {
                return @mysql_query("SET NAMES '".$this->escape_str($charset)."' COLLATE '".$this->escape_str($collation)."'", $this->conn_id);
        }

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

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

        /**
         * 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 @mysql_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($sql)
        {
                // "DELETE FROM TABLE" returns 0 affected rows This hack modifies
                // the query so that it returns the number of affected rows
                if ($this->delete_hack === TRUE)
                {
                        if (preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))
                        {
                                $sql = preg_replace("/^\s*DELETE\s+FROM\s+(\S+)\s*$/", "DELETE FROM \\1 WHERE 1=1", $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('SET AUTOCOMMIT=0');
                $this->simple_query('START TRANSACTION'); // can also be BEGIN or BEGIN WORK
                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');
                $this->simple_query('SET AUTOCOMMIT=1');
                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');
                $this->simple_query('SET AUTOCOMMIT=1');
                return TRUE;
        }
        
        // --------------------------------------------------------------------

        /**
         * Escape String
         *
         * @access      public
         * @param       string
         * @return      string
         */
        function escape_str($str)       
        {       
                if (is_array($str))
                {
                        foreach($str as $key => $val)
                        {
                                $str[$key] = $this->escape_str($val);
                        }
                
                        return $str;
                }

                if (function_exists('mysql_real_escape_string') AND is_resource($this->conn_id))
                {
                        return mysql_real_escape_string($str, $this->conn_id);
                }
                elseif (function_exists('mysql_escape_string'))
                {
                        return mysql_escape_string($str);
                }
                else
                {
                        return addslashes($str);
                }
        }
                
        // --------------------------------------------------------------------

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

        /**
         * Insert ID
         *
         * @access      public
         * @return      integer
         */
        function insert_id()
        {
                return @mysql_insert_id($this->conn_id);
        }

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

        /**
         * "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 " . $this->_protect_identifiers($table, TRUE, NULL, FALSE));
                
                if ($query->num_rows() == 0)
                        return '0';

                $row = $query->row();
                return (int)$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)
        {
                $sql = "SHOW TABLES FROM ".$this->_escape_char.$this->database.$this->_escape_char;     

                if ($prefix_limit !== FALSE AND $this->dbprefix != '')
                {
                        $sql .= " LIKE '".$this->dbprefix."%'";
                }

                return $sql;
        }
        
        // --------------------------------------------------------------------

        /**
         * Show column query
         *
         * Generates a platform-specific query string so that the column names can be fetched
         *
         * @access      public
         * @param       string  the table name
         * @return      string
         */
        function _list_columns($table = '')
        {
                return "SHOW COLUMNS FROM ".$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($table)
        {
                return "SELECT * FROM ".$table." LIMIT 1";
        }

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

        /**
         * The error message string
         *
         * @access      private
         * @return      string
         */
        function _error_message()
        {
                return mysql_error($this->conn_id);
        }
        
        // --------------------------------------------------------------------

        /**
         * The error message number
         *
         * @access      private
         * @return      integer
         */
        function _error_number()
        {
                return mysql_errno($this->conn_id);
        }

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

        /**
         * Escape the SQL Identifiers
         *
         * This function escapes column and table names
         *
         * @access      private
         * @param       string
         * @return      string
         */
        function _escape_identifiers($item)
        {
                if ($this->_escape_char == '')
                {
                        return $item;
                }
        
                if (strpos($item, '.') !== FALSE)
                {
                        $str = $this->_escape_char.str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item).$this->_escape_char;                    
                }
                else
                {
                        $str = $this->_escape_char.$item.$this->_escape_char;
                }
                
                // remove duplicates if the user already included the escape
                return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);
        }
                        
        // --------------------------------------------------------------------

        /**
         * 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, $values)
        {       
                return "INSERT INTO ".$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):'';
        
                $sql = "UPDATE ".$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($table)
        {
                return "TRUNCATE ".$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, $offset)
        {       
                if ($offset == 0)
                {
                        $offset = '';
                }
                else
                {
                        $offset .= ", ";
                }
                
                return $sql."LIMIT ".$offset.$limit;
        }

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

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


/* End of file mysql_driver.php */
/* Location: ./system/database/drivers/mysql/mysql_driver.php */