BCNFn

BCNFn is a term that refers to a specific property in relational database theory. It is a normalization form that extends the concept of Boyce-Codd Normal Form (BCNF). While BCNF aims to eliminate anomalies by ensuring that every determinant is a candidate key, BCNFn introduces further constraints to achieve a higher degree of data integrity.

A relation is in BCNFn if it is in BCNF and for every non-trivial functional dependency X -> Y, X is a superkey. This means that not only must all determinants be candidate keys, but also that any set of attributes that determines another set must be a superkey of the relation. This stricter condition helps to prevent certain types of update, insertion, and deletion anomalies that might still exist in relations that are only in BCNF.

The primary goal of achieving BCNFn is to minimize redundancy and ensure that data is stored in a way that is as independent as possible. By decomposing relations to satisfy BCNFn, database designers can create more robust and maintainable schemas. However, achieving BCNFn can sometimes lead to a larger number of smaller relations, which might increase the complexity of queries due to the need for more joins. The decision to normalize to BCNFn, or another normal form, involves a trade-off between data integrity and query performance.