1. An enterprise key is a primary key whose value is unique for a given relation.

A. True
B. False

2. A composite attribute does not get mapped into a relation.

A. True
B. False

3. A relation is a two-dimensional table.

A. True
B. False

4. Weak entities do not get mapped into a relation.

A. True
B. False

5. A primary key may be null.

A. True
B. False