Which of the following defines entity integrity constraint?
2022
Which of the following defines entity integrity constraint?
- A.
The value of primary key cannot be null.
- B.
The value of foreign key cannot be null.
- C.
The value of prime attribute cannot be null.
- D.
The value of non-prime attribute cannot be null.
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Correct answer: A
Entity integrity ensures that every row in a table is uniquely identifiable. This constraint mandates that the primary key column cannot contain null values, as nulls would prevent unique identification of records.