Functional depandicies by chris

First normal form

staffelwg2 — 2024-05-13 14:31:35 UTC

Attribute values must be atomic (no tuples)

Second normal form

staffelwg2 — 2024-05-13 14:31:59 UTC

An Attribute, that isn‘t contained in a candidate key is not partially functionally dependent on a candidate key. This means that an attribute (not contained in any candidate key) can‘t be functionally determined by a proper subset of a candidate key

Third normal form

staffelwg2 — 2024-05-13 14:32:29 UTC

X —> A is trivial (X —> or XY —> Y)
X is a superkey
A is contained in an candidate key

Fourth normal form

staffelwg2 — 2024-05-13 14:33:10 UTC

What are the prerequisites to be in BCNF?
- X —> A is trivial (X —> or XY —> Y)
- X is a superkey
- In simple terms: Each determinant is a candidate key. Each non-key attribute is dependent only on the candidate key.
- How to get into fourth normal form

Multivalued dependencies

staffelwg2 — 2024-05-13 14:35:44 UTC

Great video!!