Boyce-Codd Normal Form (BCNF)

BCNF helps reduce data duplication and ensures accurate data storage in relational databases

By Kevin McAleer,    3 Minutes


Aside: “The Truth, the Whole Truth, and Nothing but the Truth, So Help Me Codd”

“The truth, the whole truth, and nothing but the truth, so help me Codd” is a phrase often used in the context of database management. It is a playful reference to the principles set forth by Edgar F. Codd, the father of the relational model of databases.

Edgar F. Codd revolutionized the field of database management with his groundbreaking work on relational databases in the 1970s. He emphasized the importance of data integrity and consistency within a database system.

By stating “the truth, the whole truth, and nothing but the truth,” Codd emphasized the need for databases to accurately and faithfully represent the real-world entities they model. It signifies the commitment to maintain the accuracy and completeness of data stored within a database.

“So help me Codd” is a humorous addition, drawing inspiration from the oath sworn by witnesses in courtrooms to tell the truth. It highlights the significance of adhering to Codd’s principles and best practices in the realm of database management.

The phrase serves as a reminder of the core principles of database design, including maintaining data integrity, eliminating data redundancy, and ensuring consistency and accuracy. Following these principles helps create reliable and trustworthy databases that accurately reflect the information they store.


Boyce-Codd Normal Form (BCNF) is an important concept in database organization. It was developed by Raymond F. Boyce and Edgar F. Codd in the 1970s. BCNF helps reduce data duplication and ensures accurate data storage in relational databases.

BCNF is an advanced level of organizing data in databases. It builds upon the ideas of a previous organization level called the Third Normal Form (3NF). BCNF focuses on how data attributes are related to each other.

In BCNF, a table is considered properly organized if each attribute uniquely determines another attribute in the table. This means that the values in one column determine the values in another column. BCNF helps prevent errors when updating, inserting, or deleting data by strictly defining these relationships.

BCNF is important because it reduces data duplication and keeps data consistent in a relational database. By following BCNF, databases can store data efficiently, ensure accuracy, and make it easier to search for specific information.

However, achieving BCNF may make the database structure more complex and require more processing power. It’s important to balance the benefits of BCNF with the practical needs of the database.

Database designers and developers should aim to understand and apply BCNF principles when organizing relational databases. By following BCNF, they can create well-structured databases that minimize duplication and maintain consistent and reliable data.


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