Referential integrity, a fundamental principle in relational databases, aims to guarantee the consistency and validity of stored data. Essentially, every foreign key value in one table must correspond to a valid primary key value in another related table. This basic rule ensures that all links between tables are correct and that no isolated data remains. Furthermore, any changes made to one table are consistently reflected in its related tables.

Referential integrity rules serve various purposes and offer undeniable advantages. They preserve data consistency by preventing inconsistencies and errors in inter-table relationships. Similarly, they help reduce duplicate and redundant data, thus optimizing storage space and query efficiency. In addition, they ensure comprehensive integrity by preventing the deletion of records on which other data depends, thereby simplifying data management by facilitating updates and deletions.

To achieve these objectives, several options are available, such as foreign key constraints, which guarantee the validity of values ​​between primary and foreign keys, or cascading, which ensures the automatic propagation of changes from the primary key to its associated foreign keys. Similarly, cascading deletion allows for the automatic removal of related records when the primary record is deleted. Finally, undo deletion prevents the unintentional loss of records if relationships exist in other tables.