Boyce-Codd Normal Form

What Does Boyce-Codd Normal Form Mean?

Boyce-Codd Normal Form (BCNF) is one of the forms of database normalization. A database table is in BCNF if and only if there are no non-trivial functional dependencies of attributes on anything other than a superset of a candidate key.

Advertisements

BCNF is also sometimes referred to as 3.5NF, or 3.5 Normal Form.

Techopedia Explains Boyce-Codd Normal Form

BCNF was developed by Raymond Boyce and E.F. Codd; the latter is widely considered the father of relational database design.

BCNF is really an extension of 3rd Normal Form (3NF). For this reason it is frequently termed 3.5NF. 3NF states that all data in a table must depend only on that table’s primary key, and not on any other field in the table. At first glance it would seem that BCNF and 3NF are the same thing. However, in some rare cases it does happen that a 3NF table is not BCNF-compliant. This may happen in tables with two or more overlapping composite candidate keys.

Advertisements

Related Terms

Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.