Re: Foreign Keys Question

At 1:55 PM -0500 12/11/08, Robert Cummings wrote:

Student attendance should be a table with rows for each student in attendance. If you want to limit the number make a check before adding another student. Don't hard code the number via fields like above or you'll find it overly ugly to add/remove students or even increase the number of allowed students. As it stands to allow 6 students you would have to add 2 more columns. With attendance controled by a table with a row for ewach attendance you would only need to update a configuration variable the determines the maximim number of allowed students in attendance. Cheers, Rob.

Rob: I see -- the solution is a table for courses, students, instructors and enrollment. The enrollment table will hold links to all (third normal). If I want to limit the number of students in a course, then just count the number of students enrolled in a specific course within the enrollment table and check that number against the maximum allowed before adding another enrollment record. Also, if a student cancels, then it's only a deletion of an enrollment record and all is right with the world. That's good. Sometimes it's good to talk things like this through -- clears the fuzzy thinking. Thanks, tedd -- ------- http://sperling.com http://ancientstones.com http://earthstones.com