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6 days ago
What is an association relationship and how does it differ from a many-to-many (N:M) relationship?
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Database Processing: Fundamentals, Design, and Implementation
Edition: 15th
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An association relationship is very similar to an N:M relationship except that the intersection table has attributes of its own. This means that in addition to the foreign key fields linking to the two strong entities, there is at least one additional field in what would otherwise be called the intersection table but is now an association table. For example, intersection table ENROLLMENT for STUDENT and CLASS showing student enrollment in each class would normally have two columns: StudentID and ClassID. However, we can turn this intersection table into an association table by adding the column Grade, which records each student's grade in each class.
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