Answer by DrabJay for How to model "Courses prerequisites" for a university?

You have some Courses:

COURSES-------course_idcourse_numbercourse_name

You need to combine one or more of these Courses with a logical operator:

COMBINATIONS------------combination_idlogical_operator (AND, OR or NOT)COMBINATION_COURSES-------------------combination_idcourse_id

You may also need to combine some of these combinations (so changing the COMBINATION_COURSES table):

COMBINATION_COURSES-------------------combination_idcourse_idsub_combination_id

where one and only one of course_id and sub_combination_id is not null.

A Course may have one of the combinations as a prerequisite (so changing the COMBINATIONS table):

COURSES-------course_idcourse_numbercourse_nameprerequisite_combination_id

EDIT

So, given your original examples your tables would be populated:

COURSES=======course_id course_name                    prerequisite_combination_id--------- ------------------------------ ---------------------------        1 Artificial Intelligence                                 12        2 Data Structures        3 Introduction to Logic        4 Mathematical Logic and Proofs         5 Calculus 1        6 Calculus 2                                              13        7 Analytical GeometryCOMBINATIONS============combination_id logical_operator-------------- ----------------            11 OR            12 AND            13 ANDCOMBINATION_COURSES===================combination_id course_id sub_combination_id-------------- --------- ------------------            11         3            11         4            12         2            12                           11            13         7            13         5

Course 1 - Artificial Intelligence has a prerequisite of the Combination 12. Combination 12 is Course 2 - Data Structures AND Combination 11. Combination 11 is Course 3 - Introduction to Logic OR Course 4 - Mathematical Logic and Proofs.

Hence, the prerequisite of Course 1 - Artificial Intelligence is Course 2 - Data Structures AND (Course 3 - Introduction to Logic OR Course 4 - Mathematical Logic and Proofs).

This structure should allow you to store any prerequisite that is the any logical combination of any number of courses.