UGC NET Questions (Paper – 1)

A primary key is chosen from among candidate keys to uniquely identify rows in a table. It enforces entity integrity by preventing duplicate and null values in that field. Proper selection of primary keys is fundamental to relational database design. Thus, the key described is the primary key.

Option A:
Option A is correct because primary key is defined as the main unique identifier for table records.

Option B:
Option B, foreign, key links records between tables but may repeat values and does not uniquely identify rows within its own table.

Option C:
Option C, candidate, key is a potential unique identifier, but once one is chosen as primary, the others are no longer labelled as primary keys.

Option D:
Option D, alternate, key refers to other candidate keys not selected as primary, which is not what the stem describes.

A foreign key is used to link related records across tables by referencing the primary key in another table. It supports referential integrity by ensuring that relationships between data remain consistent. This design allows relational databases to model complex structures. Therefore, the key described is a foreign key.

Option A:
Option A, primary, key uniquely identifies records within its own table but does not specifically represent a reference to another table.

Option B:
Option B is correct because foreign key is defined as a field that points to a primary key in another table, establishing relationships.

Option C:
Option C, composite, key refers to a key made of more than one field, which can be primary or candidate but is not necessarily a cross table reference.

Option D:
Option D, super, key is any set of attributes that uniquely identifies rows and is broader than the specific concept of foreign keys.