解析link_mysql的php版

$str_sql_read="select count(*) as num from userinfo";
$str_sql_del="delete from userinfo where id =1";
$res =link_mysql("read",$str_sql_read);
$res_del =link_mysql("delete",$str_sql_del);
echo $res_del."
";
while($row = mysql_fetch_assoc($res))
{
echo "".$row['num']."
";
}

?>

function link_mysql($opt,$str_sql)
{
$con = mysql_connect("localhost","root","root") or die ('Not connected : ' . mysql_error());
mysql_set_charset("gbk",$con);
//if you donot know how to use this function,find it defination;
mysql_select_db("website",$con);
switch($opt){
case "read":
$res =mysql_query($str_sql);
break;
case "update":
case "delete":
case "insert":
$res =mysql_query($str_sql);
break;
}
mysql_close();
return $res;
}
?>