php连接数据库类

框架用多啦,别忘记了原生,多练练手 phpmysqli 链接数据库

<?phpclass mysql{    private $db_name;    private $db_host;    private $db_user;    private $db_pwd;    private $conn;    private $querysql;    private $result;    private $resultarray=array();    private $row;    //创建构造函数 数据库名 主机名 用户名 密码    function __construct($dbname,$dbhost,$dbuser,$dbpwd){        $this->db_name=$dbname;        $this->db_host=$dbhost;        $this->db_pwd=$dbpwd;        $this->db_user=$dbuser;    }    //连接数据库    private function db_connect(){        $this->conn = mysqli_connect($this->db_host,$this->db_user,$this->db_pwd,$this->db_name) or die("Could not Connect MySql Server");        return $this->conn;    }    //选择数据库    private function selectdb(){        mysql_select_db($this->db_name) or die("unable to select dbname");    }    //执行sql语句    private function query($sql){        $conn = self::db_connect();        return $this->result=mysqli_query($conn,$sql);    }    //$result返回值为 bool类型 false为没有数据    private function get_num($result){        return $this->num=mysqli_num_rows($result);    }    //执行结果 返回数据    public function get_result($sql){        $result = $this->query($sql);        if($this->get_num($result)>0){            //mysql_fetch_assoc()和 mysql_fetch_array(,MYSQL_ASSOC)从结果集中取得一行作为关联数组 没有则返回false            while($this->rows=mysqli_fetch_array($result)){            //赋值 数组赋值 resultarray[]= 将影响的行数赋值给数组            $this->resultarray[]=$this->rows;            }            return $this->resultarray;        }else{            echo "暂无数据!";        }    }    //版本信息    function version() {         $conn = self::db_connect();        return mysqli_get_server_info($conn);    }    //关闭资源    function close() {        $conn = self::db_connect();        return mysqli_close();    }    //向$table表中插入值    function fn_insert($table,$name,$value){        $this->query("insert into $table ($name) value ($value)");    }    //根据$id值删除表$table中的一条记录    function fn_delete($table,$id,$value){        $this->query("delete from $table where $id=$value");        echo "id为". $id." 的记录被成功删除!";    }}$m = new mysql("admin","127.0.0.1","root","root");$arreresult = $m->get_result("select * from yii_msg");