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CBSE Class 12 Informatics Practices Question 28 of 44

Solved 2025 Sample Question Paper CBSE Class 12 Informatics Practices (065) — Question 7

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Question 26

Define the term Primary Key in a database. Explain how it is different from a Candidate Key.

Answer

A primary key is a set of one or more attributes/fields that can uniquely identify tuples/rows within the relation (table). It must contain unique values and cannot be null.

A candidate key, on the other hand, refers to all the attributes in a relation that are candidates or are capable of becoming a primary key. A table can have multiple candidate keys, but only one of them is chosen as the primary key.