php连接MySQL的类，支持读写分离

来源：互联网发布：matlab求矩阵行列式编辑：程序博客网时间：2024/06/07 20:56
<?php/** * MySQL读写分离类的实现 * $db_config = array( *          'master' => array('host'=>'localhost:3306','user'=>'admin','passwd'=>'123456','db'=>'stat'), *          'slave'  => array( *                           array('host'=>'localhost:3307','user'=>'admin','passwd'=>'123456','db'=>'stat'), *                           array('host'=>'localhost:3308','user'=>'admin','passwd'=>'123456','db'=>'stat') *                      ) *  ); *   *  注释：如果slave有多个时随机连接其中的一个 *//*$db_config = array(    'master' => array('host'=>'localhost:3306','user'=>'admin','passwd'=>'123456','db'=>'stat'),    'slave'  => array(                    array('host'=>'localhost:3307','user'=>'admin','passwd'=>'123456','db'=>'stat'),                    array('host'=>'localhost:3308','user'=>'admin','passwd'=>'123456','db'=>'stat')                ));$db = MySQL::getInstance('','r-w');$sql = "select * from admin";$rs = $db->query($sql);while ($row = $db->fetch($rs)){    echo "uid:".$row['uid']."   ".$row['userName']."<br />";}echo "<hr />"; */class MySQL{        private static $_instance = null;//数据库连接实例    private static $_master = null;//主数据库连接实例    private static $_slave = null;//重数据库连接实例        public $_config = array();//数据库连接配置信息    public $_res = null;//查询实例句柄    public $_flag = '';//标识当前语句是在主还是重数据库上执行    public $_link = null;        /**     * 单实例     * Enter description here ...     * @param unknown_type $dbname     * @param unknown_type $mode     */    public static function & getInstance($dbname='',$mode='rw'){        if (is_null(self::$_instance)){            self::$_instance = new self();            self::$_instance->__getConf();            self::$_instance->connect($dbname,$mode);        }                return self::$_instance;    }    /**     * 获取数据库配置信息     * Enter description here ...     */    public function __getConf(){        global $db_config;        $this->_config['master'] = $db_config['master'];        $this->_config['slave'] = $db_config['slave'];    }        /**     * 数据库连接     * Enter description here ...     * @param $dbname 指定连接的数据库名，默认情况下连接配置文件的库     * @param $mode rw表示连接主库，r-w表示读写分离        */    public function connect($dbname='',$mode = 'rw'){        if($mode == 'rw'){            if(is_null(self::$_master)){                $this->_master = $this->_slave = $this->conn_master($dbname);            }        }else{            if(is_null(self::$_master)){                $this->_master = $this->conn_master($dbname);            }            if(is_null(self::$_slave)){                $this->_slave = $this->conn_slave($dbname);            }        }    }        /**     * 连接到主数据库服务器     * Enter description here ...     */    public function conn_master($dbname=''){        $_link = mysql_connect($this->_config['master']['host'],$this->_config['master']['user'],$this->_config['master']['passwd'],true) or die ("Connect ".$this->_config['master']['host']." fail.");        mysql_select_db(empty($dbname)?$this->_config['master']['db']:$dbname,$_link) or die(" The DB name ".$this->_config['master']['db']." is not exists.");        mysql_query("set names utf8",$_link);        return $_link;    }        /**     * 连接到从数据库服务器     * Enter description here ...     */    public function conn_slave($dbname=''){        $offset = rand(0,count($this->_config['slave'])-1);        $_link = @mysql_connect($this->_config['slave'][$offset]['host'],$this->_config['slave'][$offset]['user'],$this->_config['slave'][$offset]['passwd'],true) or die(" Connect ".$this->_config['slave'][$offset]['host']." fail.");        mysql_select_db(empty($dbname)?$this->_config['slave'][$offset]['db']:$dbname,$_link) or die(" The DB name ".$this->_config['slave'][$offset]['db']." is not exists.");        mysql_query("set names utf8",$_link);        return $_link;    }    /**     * 执行数据库查询     * Enter description here ...     * @param string $sql     */    public function query($sql,$master=true){        if($master == true || (substr(strtolower($sql),0,6) != 'select') && $master == false){            $this->_res = mysql_query($sql,$this->_master);            if(!$this->_res){                $this->_error[] = mysql_error($this->_master);            }            $this->_flag = 'master';            $this->_link = $this->_master;        } else {            $this->_res = mysql_query($sql,$this->_slave);            if(!$this->_res){                $this->_error[] = mysql_error($this->_slave);            }            $this->_flag = 'slave';            $this->_link = $this->_slave;        }        return $this->_res;    }        /**     * 获取单行记录     * Enter description here ...     * @param mixed $rs     */    public function get($rs=''){        if(empty($rs)){            $rs = $this->_res;        }        return mysql_fetch_row($rs);    }        /**     * 获取多行记录     * Enter description here ...     * @param mixed $rs     * @param  $result_type     */    public function fetch($rs = ''){        if(empty($rs)){            $rs = $this->_res;        }        return mysql_fetch_array($rs,MYSQL_ASSOC);    }        /**     * 插入数据     * Enter description here ...     * @param unknown_type $sql     */    public function add($sql){        $rs = $this->query($sql);        if($rs)            return mysql_insert_id($this->_link);        return false;    }        /**     * 更新数据     * Enter description here ...     * @param unknown_type $sql     */    public function update($sql){        if(empty($sql)) return false;        $rs = $this->query($sql);        if($rs)            return $this->fetchNum();        return false;    }    /**     * 获取上一条语句影响的行数     * Enter description here ...     */    public function fetchNum(){        return mysql_affected_rows($this->_link);    }        /**     * 析构函数,释放数据库连接资源     * Enter description here ...     */    public function __destruct(){        mysql_close($this->_link);    }}
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