What is a foreign key?(a) A foreign key is a primary key of a relation which is an attribute in another relation(b) A foreign key is a superkey of a relation which is an attribute in more than one other relations(c) A foreign key is an attribute of a relation that is a primary key of another relation(d) A foreign key is the primary key of a relation that does not occur anywhere else in the schema

What is a foreign key?(a) A foreign key is a primary key of a relation

1.	What is a foreign key?(a) A foreign key is a primary key of a relation which is an attribute in another relation(b) A foreign key is a superkey of a relation which is an attribute in more than one other relations(c) A foreign key is an attribute of a relation that is a primary key of another relation(d) A foreign key is the primary key of a relation that does not occur anywhere else in the schema
Answer» Correct answer is (c) A foreign key is an attribute of a relation that is a primary key of another relation The explanation is: A foreign key is an attribute of a relation that is initially a primary key of another relation. A foreign key usage preserves referential integrity.

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