Three tables and one * * * students, grades, grades

There are student number (xsid) and name (xsname) in the student list.

Grade category includes grade category number (cjid) and grade category name (cjname).

There are two foreign keys in the grade table, namely the student number (xsid) and the grade category number (cjid), including the score.

Together, these three tables can meet your needs and meet three examples.