Which statement best describes the difference between relational integrity and referential integrity?

Which statement best describes the difference between relational integrity and referential integrity?

• A. Referential integrity requires every row to have a null foreign key.
• B. Relational integrity enforces encryption of data across the database.
• C. Relational integrity ensures the validity of relationships between tables.
• D. Referential integrity ensures that all data in non-key columns are unique.

Answer: (C)

Relational integrity is about keeping data in related tables consistent and meaningful, ensuring the relationships among tables stay valid. Referential integrity is a specific rule within that broader idea: a value in a foreign key must exist as a primary key in the related table (or be null if the relationship allows it). Because of this, the statement that relational integrity ensures the validity of relationships between tables best captures the broader concept. The other statements misalign with what integrity means here: encryption is a security concern, not an integrity constraint; requiring every row to have a null foreign key would break useful links between tables; and requiring non-key columns to be unique is about uniqueness constraints, not maintaining relational links.

Relational integrity is about keeping data in related tables consistent and meaningful, ensuring the relationships among tables stay valid. Referential integrity is a specific rule within that broader idea: a value in a foreign key must exist as a primary key in the related table (or be null if the relationship allows it). Because of this, the statement that relational integrity ensures the validity of relationships between tables best captures the broader concept. The other statements misalign with what integrity means here: encryption is a security concern, not an integrity constraint; requiring every row to have a null foreign key would break useful links between tables; and requiring non-key columns to be unique is about uniqueness constraints, not maintaining relational links.