PHP encapsulated connection Mysql class and usage analysis

class mysql{
private $db_name;
private $db_host;
private $db_user;
private $db_pwd;
private $conn;
private $querysql;
private $result;
private $resultarray=array();
private $row;
//创建构造函数 数据库名 主机名 用户名 密码
function __counstruct($dbname,$dbhost,$dbuser,$dbpwd){
$this->db_name=$dbname;
$this->db_host=$dbhost;
$this->db_pwd=$dbpwd;
$this->db_user=$dbuser;
$this->dbconnect();
$this->selectdb();
}
//连接数据库
private function db_connect(){
$this->conn=mysql_connect($this->db_host,$this->db_user,$this->db_pwd) or die("Could not Connect MySql Server");
}
private function selectdb(){
mysql_select_db($this->db_name) or die("unable to select dbname")
}
private function query(){
return $this->result=mysql_query($this->querysql);
}
private function get_result($sql){
$this->querysql=$sql;
$this->query();
if($this->get_num()>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($this->rows=mysql_fetch_array($this->result)){
//赋值 数组赋值 resultarray[]= 将影响的行数赋值给数组
$this->resultarray[]=$this->rows
}
return $this->resultarray;
}
}
//$result返回值为 bool类型 false为没有数据
private function get_num(){
return $this->num=mysql_num_rows($this->result);
}
}
$m=new mysql("testuser","localhost","root","root");
$arreresult=$m->get_result("select * from userinfo");