Er course selection system, a course of course, is the primary key of the curriculum, and each course has a courses outside key (quoted in the curriculum course number),
That if a course has multiple ap classes, that is the content of the foreign key is multiple courses, how to deal with?
Is to modify the data type into a longer char, and is said to be a table level of integrity constraints (on the second day, learn SQL, are less likely to be the problem)

CodePudding user response:

Usually do a relational table, record number to the primary key of the curriculum and courses