In relational database design, what is an attribute or set of attributes that uniquely identifies every tuple in a table without containing null values?
Answer and explanation
Correct answer: B. Primary key
- Step 1: A primary key enforces entity integrity in a relational table. Step 2. It guarantees that every row is distinct and accessible without ambiguity, forbidding NULL values. Answer: Primary key. Why not the others: A foreign key points to a primary key in another table; composite index speeds searches; surrogate candidate is an alternate candidate key.
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