duplicate / null problem

[cuttsy]

I have the following database to track school children (Mentees) that attend our academic sessions.

tblMentees(menteeID, fName, sName, school, year)

tblSchools(schoolID, schoolName, schoolType, address)

tblSessions(sessionID, mentorName, date, start, end, activity)

tblMenteeToSession(Mentee, Session)

tblActivity(activityID, activityName, description)

the problem I have is that when a user is going through the motions of adding children to the attended list on the session form if they add all of the children in the database which is likely early on in its use then there can be a problem.

Say they add every child to the session then they add one of them for a second time access will tell them no duplicates of a primary key. If they try to click delete it will tell them again and re set the focus to the same object. If they delete the text in the combobox access tells them that a null value is not permitted. The only way out is to close down access.

what should i be doing to prevent this trap?

 

[cuttsy]

thanks

thanks.

Will the cancel button work as it seems that every time that I click away from the combobox the error comes up before anything else is allowed to happen.

thanks for the table tips too.