Normal Forms III
Learning Objectives
- Recognize Armstrong’s axioms to infer all functional dependencies for a relational schema
- Describe Boyce Codd Normal Form (BCNF)
- Decompose a relational schema into 3NF based on the schema’s functional dependencies
How to Complete this Lesson
Complete the following learning activities: (2.25–2.75 hours total)
- Attend the class meeting
(60 minutes)
- Complete the handout
- Take the quiz (10 minutes)
- Start the ER diagram for the project
(60–90 minutes)
- Sketch the entities, attributes, and relationships (with cardinalities and modalities)
Due
As a reminder, the following is due this lesson:
Resources
- Questions for logical database design (90–120 minutes)
Further Information
Edgar F. Codd defined first normal form (1NF) in his seminal paper “A Relational Model of Data for Large Shared Data Banks” (Codd 1970). He later defined the second and third normal forms (2NF and 3NF) and contributed to the development of Boyce-Codd normal form (BCNF), which eliminates all redundancy that can be discovered from the functional dependencies among attributes. Higher-level normal forms exist, such as fourth normal form (4NF), which addresses redundancy due to multivalued dependencies. 4NF was invented by Ronald Fagin, Professor Barry Fagin’s cousin.