Listing 1. Example Database Table

Seminars
ID title cost places_left
1 Python Programming 200 15
2 Intro to Linux 100 32
3 Socket Programming 475 7
4 Web Commerce 300 26
Attendees
name seminar paid
Albert 1 no
Albert 4 no
Beth 1 yes
Chuck 2 no
Dale 4 yes
Elaine 3 yes
Elaine 1 yes
Felix 4 no