Stuent(studentid, age)course(course_id, coursename)sc(studentid, course_id)
There already was N in assuming Sc is expressed record, want to inquire the student's Id and curricular Id now, and same a student and same door course can inquire only, the proposal with good what does everybody have? Did not see the effect that SC expresses, be associated Student watch and Course watch?
If so, it is not OK that is a StudentID added in Course the outside and the inside? Inserting a field in Sc watch, the structure is as follows Sc(student_id, course_id, address)
Requirement or aboveUse 3 watches to make associated use DISTINCTI am dizzy, it is inquiry, either insert or update
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