6 lessons
A complete tour of integrity constraints
Domain, entity, referential, and key constraints gathered into one formal picture, plus general assertions and how constraints connect to everything covered so far.
Functional dependencies and Armstrong's axioms
The formal definition of a functional dependency, trivial vs non-trivial dependencies, and the three inference rules that let you derive every dependency implied by a given set.
First, Second, and Third Normal Form
The three foundational normal forms explained through the update, insertion, and deletion anomalies they each eliminate, with worked decomposition examples.
Boyce-Codd Normal Form (BCNF)
The subtle gap 3NF leaves open with overlapping candidate keys, the stricter BCNF definition that closes it, and why BCNF sometimes trades away dependency preservation.
Multivalued dependencies, 4NF, and 5NF
What happens when a single-valued functional dependency isn't enough to describe a table's redundancy, and the two higher normal forms built to handle it.
Decomposition properties — lossless join and dependency preservation
The two correctness guarantees every normalization decomposition must satisfy, with the exact test for each and worked examples of what happens when they fail.