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CBSE Class 12 Computer Science Question 7 of 78

Relational Databases — Question 7

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Question

Question 7

Assertion. All types of keys contain unique values for each row.

Reason. A foreign-key attribute of a table is the primary key of another table.

Answer

(d)

Assertion is false but Reason is true.

Explanation
Not all types of keys necessarily contain unique values for each row. While primary keys ensure uniqueness for each row in a table, other types of keys, such as foreign keys and candidate keys, may not guarantee uniqueness. A non-key attribute, whose values are derived from the primary key of some other table, is known as foreign key in its current table.