Logical Database Design – General Questions

11. A relation has which of the following properties?

A. Each row is not unique.
B. Attributes can have the same name within a given table.
C. Each relation has a unique name.
D. The order of the columns is significant.

Correct Answer: C. Each relation has a unique name.

12. When mapping a ternary relationship with an associative entity into a relation which of the following is true?

A. One relation is created.
B. Two relations are created.
C. Three relations are created.
D. Four relations are created.

Correct Answer: D. Four relations are created.

13. When mapping a regular entity into a relation which of the following is true?

A. One relation is created.
B. Two relations are created.
C. Three relations are created.
D. Four relations are created.

Correct Answer: A. One relation is created.

14. When mapping a supertype/subtype relationship which of the following is true?

A. The supertype primary key is assigned to each subtype.
B. The subtype primary key is assigned to each supertype.
C. There is no link between the supertype/subtype entities.
D. There is no primary key/foreign key relationship between a supertype/subtype.

Correct Answer: A. The supertype primary key is assigned to each subtype.

15. Relations are:

A. two-dimensional tables.
B. three-dimensional tables.
C. four-dimensional tables.
D. five-dimensional tables.

Correct Answer: A. two-dimensional tables.

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