Multivalued dependencies should be eliminated
Correct answer: B. commonly
- A. always
- B. commonly
- C. seldom
- D. never
Explanation
Multivalued dependencies (MVDs) are a type of dependency that can occur in relational databases. An MVD says that a certain set of attributes (determinant) determines another set of attributes (dependent). In simpler terms, if you know the value of one set of attributes, you can always know the value of another set of attributes. However, MVDs can lead to data redundancy and anomalies. For example, imagine a table that stores information about courses and the students enrolled in those courses. If there is an MVD that says "CourseID determines StudentID", then this means that a student can only be enrolled in one course. But what if a student can enroll in multiple courses? In this case, the table would need to be duplicated for each course that a student is enrolled in, which would lead to data redundancy. To avoid these problems, database designers try to eliminate MVDs whenever possible. This can be done by decomposing the table into smaller tables that are in a higher normal form
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