Which of the following describes a candidate key?

Which of the following describes a candidate key?

• A. Any set of attributes
• B. Attributes that do not uniquely identify an entity
• C. A minimal set of identifiers for an entity instance
• D. Only primary keys

Answer: (C)

A candidate key is defined as a minimal set of attributes necessary to uniquely identify an entity instance within a dataset. This means that every attribute within this set contributes to the unique identification, and removing any attribute would cause it to no longer provide uniqueness. In the context of database design, the concept of a candidate key is crucial, as it allows for the identification of potential primary keys. While there can be multiple candidate keys for a single entity, only one of these will ultimately be chosen as the primary key. However, each candidate key must satisfy the uniqueness requirement for identifying records in the database. The other definitions do not accurately capture the correct characteristics of a candidate key. For instance, a random set of attributes does not guarantee uniqueness, and a group of attributes that cannot uniquely identify an entity does not qualify as a candidate key. Similarly, limiting the definition to only primary keys overlooks the broader context where candidate keys may exist without being designated as the primary key.

A candidate key is defined as a minimal set of attributes necessary to uniquely identify an entity instance within a dataset. This means that every attribute within this set contributes to the unique identification, and removing any attribute would cause it to no longer provide uniqueness.

In the context of database design, the concept of a candidate key is crucial, as it allows for the identification of potential primary keys. While there can be multiple candidate keys for a single entity, only one of these will ultimately be chosen as the primary key. However, each candidate key must satisfy the uniqueness requirement for identifying records in the database.

The other definitions do not accurately capture the correct characteristics of a candidate key. For instance, a random set of attributes does not guarantee uniqueness, and a group of attributes that cannot uniquely identify an entity does not qualify as a candidate key. Similarly, limiting the definition to only primary keys overlooks the broader context where candidate keys may exist without being designated as the primary key.