A ______ is the candidate key selected as the main unique identifier for each…
2020
A ______ is the candidate key selected as the main unique identifier for each row in a table. It must contain unique values and cannot contain NULL values.
- A.
foreign key
- B.
natural key
- C.
candidate key
- D.
primary key
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Correct answer: D
A candidate key is any minimal attribute or set of attributes that can uniquely identify a row.
A primary key is the candidate key selected as the main unique identifier for the table. It must be unique and cannot contain NULL values.
Since the question asks for the selected main unique identifier, the correct answer is primary key.
Correct option: D