Referential integrity is defined by which of the following?

Referential integrity is defined by which of the following?

• A. Foreign key in one table must match the primary key in another table
• B. It ensures that every value in every table is unique
• C. It prevents duplicates within a single table
• D. It encrypts data across related tables

Answer: (A)

Referential integrity ensures that relationships between tables stay consistent. It is achieved by placing a foreign key in a child table that must correspond to an existing primary key in a parent table, so every referenced value actually exists. This guarantees you don’t end up with references to non-existent records and helps prevent orphaned data when records are updated or removed. It’s not about making every value across all tables unique or preventing duplicates within a single table (that’s about general uniqueness constraints or primary keys within one table), and it has nothing to do with encrypting data across related tables.

Referential integrity ensures that relationships between tables stay consistent. It is achieved by placing a foreign key in a child table that must correspond to an existing primary key in a parent table, so every referenced value actually exists. This guarantees you don’t end up with references to non-existent records and helps prevent orphaned data when records are updated or removed. It’s not about making every value across all tables unique or preventing duplicates within a single table (that’s about general uniqueness constraints or primary keys within one table), and it has nothing to do with encrypting data across related tables.