Which type of relationship involves one record in a table that associates with only one record in another table?

• A. One-to-many relationship
• B. One-to-one relationship
• C. Many-to-many relationship
• D. Hierarchy relationship

Answer: (B)

A one-to-one relationship occurs when a record in one table corresponds to exactly one record in another table. This means that for every entry in the first table, there is a unique entry in the second table that it is associated with. This relationship is useful in scenarios where you might have distinct data that logically belongs but does not need to be stored in the same table for various reasons such as normalization, access speed, or modular design.

For example, consider a database for an organization where each employee has a unique employment record, and each employment record may be associated with only one employee. This setup highlights how a one-to-one relationship structures data, ensuring that the integrity and uniqueness of the associations are maintained. Overall, this relationship type emphasizes the uniqueness and exclusivity of the association between corresponding records in the thereby establishing a clear link without redundancy.