Which of the following best defines an identifier in data management?

• A. A unique value for each business entity.
• B. A data type used for numeric values.
• C. A password used for logins.
• D. A backup file name.

Answer: (A)

An identifier is a value that uniquely identifies a single entity in a dataset. This distinctness lets you distinguish one record from another and link related data across tables, which is essential for reliable data retrieval, updates, and relationships. In databases, identifiers often serve as primary keys or unique keys, and they’re usually stable so references don’t break over time. Examples include customer IDs, product codes, or employee numbers.

It’s not a numeric data type—that describes how data is stored, not its role in distinguishing records. It isn’t a password used for logins, which are credentials for authentication. It isn’t a backup file name, which is just a label. Therefore, a unique value for each business entity best defines an identifier.