To maintain data integrity within a relational database, what key design aspect must be upheld when references are made across tables?

The correct answer is referential integrity. This concept is essential in relational databases because it ensures that relationships between tables remain consistent. When a table references another table, referential integrity enforces rules that protect the validity of these references. For example, if a foreign key in one table points to a primary key in another, referential integrity ensures that every foreign key entry corresponds to a valid primary key entry. This prevents orphaned records—instances where a record in one table points to a record in another table that does not exist.

By maintaining referential integrity, databases ensure that relationships between tables do not lead to inconsistencies, which is crucial for data accuracy and reliability. It is a fundamental principle that maintains data integrity and can help prevent data anomalies during insert, update, or delete operations.

In contrast, while data normalization helps organize the database to reduce redundancy, it does not specifically enforce the relationships between tables. Database indexing improves performance and speed of data retrieval, but it does not impact the integrity of references across tables. Access control mechanisms, although critical for security and user permissions, do not directly affect data integrity within the relational model. Each of these elements plays a role in database management, but referential integrity is the key aspect specifically related to maintaining