How is a one-to-one relationship defined in database terms?

A one-to-one relationship in database terms is characterized by a specific pairing between records in two tables. Specifically, this means that each record in Table A is linked to only one record in Table B, and vice versa. This unique pairing ensures that for every entry in Table A, there exists a corresponding and exclusive entry in Table B.

For instance, consider two tables: one for employees and one for employee badges. In this scenario, each employee would have exactly one badge assigned to them, and each badge would only be assigned to one specific employee. This clear and direct association exemplifies the one-to-one relationship, affirming that each record in Table A (employees) can have only one matching record in Table B (badges).

In contrast, the other options describe different types of relationships. A scenario where each record in Table A can have multiple matching records in Table B refers to a one-to-many relationship. If many records in Table A correspond to many records in Table B, that exemplifies a many-to-many relationship. Lastly, if one record in Table A connects to none in Table B, that reflects a potential situation of absence but not a defined relationship structure like one-to-one. Therefore, the definition of a one-to-one relationship