Which of the following describes a non-key attribute?

Which of the following describes a non-key attribute?

• A. An attribute that helps define a primary key
• B. An attribute that is part of a foreign key
• C. An attribute that does not uniquely identify an entity
• D. Only attributes that relate to integer values

Answer: (C)

A non-key attribute is best described as an attribute that does not uniquely identify an entity. In a database context, entities are typically defined by their unique identifiers known as primary keys. Non-key attributes provide more information about the entity but do not contribute to establishing that uniqueness. For instance, in a customer database, the customer ID might serve as the primary key to uniquely identify each customer, while attributes like name, email, or phone number provide additional details without being unique identifiers. The other options involve attributes that have specific relational database functions or characteristics. An attribute that helps define a primary key refers to characteristics that may aid in building a unique identifier, which does not align with the concept of a non-key attribute. An attribute that is part of a foreign key connects to relationships between tables but still has implications for unique identification within those contexts. Lastly, the statement regarding attributes that relate only to integer values is too restrictive, as non-key attributes can include various types, such as strings, dates, or other data types, reflecting diverse data features beyond just integers.

A non-key attribute is best described as an attribute that does not uniquely identify an entity. In a database context, entities are typically defined by their unique identifiers known as primary keys. Non-key attributes provide more information about the entity but do not contribute to establishing that uniqueness. For instance, in a customer database, the customer ID might serve as the primary key to uniquely identify each customer, while attributes like name, email, or phone number provide additional details without being unique identifiers.

The other options involve attributes that have specific relational database functions or characteristics. An attribute that helps define a primary key refers to characteristics that may aid in building a unique identifier, which does not align with the concept of a non-key attribute. An attribute that is part of a foreign key connects to relationships between tables but still has implications for unique identification within those contexts. Lastly, the statement regarding attributes that relate only to integer values is too restrictive, as non-key attributes can include various types, such as strings, dates, or other data types, reflecting diverse data features beyond just integers.