E-R Diagram Relational reduction results with the student_account relation set b

Question

E-R Diagram Relational reduction results with the student_account relation set being: student_account(student_id, account_id) The student_account relation is forced to not allow null for every attribute in the relation. Based on the Entity-Relation diagram above, which attribute/atributes or combination of attributes should be constrained to be unique? Because the lucid_account relation is not involved with any other entity set, this schema can be simplified. Combine two of the three relations into one relation and give the resulting schema of two relations.

Explanation / Answer

1.

In student_account relation the attributes student_id and account_id should be constrained t o be unique.

2.

The two relations can be

student <---------- has -----------------student_account

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