Explain the concept of referential integrity in the context of database normalization.

Referential integrity is a fundamental concept in database normalization that ensures the consistency and accuracy of data relationships within a database. It is a set of rules that define the relationships between tables in a relational database and ensures that these relationships are maintained and enforced.

In the context of database normalization, referential integrity ensures that any foreign key values in a table must correspond to a primary key value in another related table. This means that every foreign key value must have a matching primary key value in the referenced table, or it must be null.

By enforcing referential integrity, the database management system (DBMS) guarantees that data relationships are valid and consistent. It prevents the creation of orphaned records, where a foreign key value references a non-existent primary key value. It also ensures that any updates or deletions in the referenced table are properly cascaded to the related tables, maintaining the integrity of the data.

Referential integrity is typically implemented through the use of constraints, such as foreign key constraints, which are defined during the database design phase. These constraints specify the relationships between tables and the actions to be taken when changes are made to the referenced table.

Overall, referential integrity plays a crucial role in maintaining the accuracy and reliability of data relationships in a normalized database. It helps to eliminate data inconsistencies, improve data quality, and ensure the integrity of the overall database structure.