RelationalDBDesign RelationalDBDesign



Third Normal Form   «Prev  Next»
Lesson 10

Third normal form Conclusion

Codd's 12 Criteria

This module covered database normalization up to 3NF, explained how normalizing a database to 3NF meets Codd's 12 criteria for a fully relational database, noted there are normal forms beyond 3NF, and discussed denormalization.
Having completed this module, you should be able to:
  1. Explain the requirements for third normal form (3NF)
  2. Identify transitive dependencies
  3. Normalize a relation to 3NF
  4. Describe Codd's 12 criteria for a fully relational RDBMS
  5. Explain how Codd's 12 criteria relate to normalization
  6. Explain what type of dependencies might require normalization beyond 3NF
  7. Define denormalization and identify when it might be useful

Glossary terms

This module introduced you to the following terms:
  1. third normal form (3NF): A table is in third normal form if it contains no transitive dependencies.
  2. denormalization: To move a table to a lower normal form (e.g., from 3NF to 2NF).
  3. determinant: An attribute upon which another attribute is functionally dependent.
  4. functional dependency: A one-way relationship between two attributes so that, for any unique value of one attribute, there is only one value of the other attribute.
  5. third normal form (3NF): A table is in third normal form if it contains no transitive dependencies.
  6. transitive dependency: A term derived from the mathematical equation for a transitive property: If a>b and b>c, then a>c. In terms of a database, a transitive dependency refers to a relationship between two entities that is dependent upon a second relationship between one of the first two entities and a third entity.
  7. transitivity: Amathematical property which states that if A
The next module discusses joins and user views.

  1. normalization to 3NF,
  2. Codd's rules,
  3. normalization beyond 3NF, and
  4. denormalization.

Third Normal Form - Quiz

Before you continue to the next module, click the Quiz link below to reinforce your understanding of Third Normal Form - Quiz