Referential Integrity refers to the ability of the database to keep related data from being corrupted. Data references between tables must remain intact. Referential Integrity means that two specific database rules must exist between tables:
•Do not delete data required by another table. Check that there are no records in related tables that require the record you are deleting.
•Do not add incomplete data to a table. Check whether related information exists in a related table before adding information to a table.