Question
Which of the following statements about a relation R in first normal form (1NF) is/are TRUE ?
Official answer and solution
- Official answer
- A and C
- From
- Official GATE 2024 answer key
Solution
Recall the definition of First Normal Form (1NF): all attribute domains must be atomic (no composite or multi-valued attributes), with no restriction on the number or size of keys.
- (A) is TRUE: A relation in 1NF can have a primary or candidate key consisting of multiple attributes (a composite key).
- (B) is FALSE: Any relation in 1NF can reference another relation via a foreign key.
- (C) is TRUE: By definition, a relation is in 1NF if and only if every attribute is atomic (indivisible); hence it cannot have composite or multi-valued attributes.
- (D) is FALSE: A 1NF relation can have multiple candidate keys.
Final answer
Options (A), (C)
Common trap
Confusing a composite attribute (non-atomic structure within a single column, forbidden in 1NF) with a composite/multi-attribute key (allowed in all normal forms).
The answer is the one in the official GATE answer key. The solution is this site's own explanation.
Source
- Paper
- GATE 2024 Computer Science and Information Technology - Set 1 (CS1)
- Question
- 22 of 65
- Section
- Computer Science and Information Technology
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