Table name: Sessions
Columns : ID, UserID, Timestamp_IN, Timestamp_OUT
Based on the info you've given, I like that simple design. There really isn't enough info though. Will the system automatically detect if it's a punch IN or OUT? Will the user specify? Etc..
It seems that you want to store a session of some sort and the time that session begins and ends. Can you punch out twice in a row without punching in? These questions are important.
