Hi. i have a table Login Info which has the following fields: Lets say:

FK
UserID, LoginID, LoginTime, Status
Composite PK

Status is showing the current status of user whether he is login or logout. What i want is that if once user logsIn so he is not allowed to login on any other place, but if he tries to do, so a message will be displayed that you are already logged In. And when he LogsOut so his current status is LoggedOut. Please guide me that how do i do this?

There are also other complexities in it, but in start i want to work on it.