php session的应用详细介绍

function _session_destroy(){
global $handle;
$sql ="delete from tb_session where session_key ='$key'";
$result =mysql_query($sql,$handle);
}

functin _session_gc($expiry_time){
global $handle;
$sql ="delete from tb_session where session_expiry_time<$expiry_time";
$result =mysql_query($sql,$handle);
return($result);
}