CS Professional · Artificial Intelligence, Data Analytics and Cyber Security - Laws and Practice · Database Management
Referential integrity in a relational database ensures that:
Referential integrity ensures every non-NULL foreign key value matches an existing primary key in the referenced table, preventing orphan records. It concerns consistency between related tables, not encryption or uniqueness of every column.
- AEvery non-NULL foreign key value matches an existing primary key value in the referenced tableCorrect
- BEvery column in a table holds a unique value
- CData stored on disk is always encrypted
- DEach table contains at least one NULL value
Explanation
Referential integrity prevents orphan records: a foreign key value must either be NULL or exist as a primary key in the parent table. It is unrelated to encryption or uniqueness of all columns.
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