Knobit of Data modelling · K-515 · Skill

Recognises a functional dependency lost in a decomposition

What it means

After a split, a dependency spans two entities and no key in either one enforces it. Typical after a BCNF split (row 11).

How it is assessed

Flags the deficient case and passes the acceptable one. Deficient: After row 11's split, nothing says a loan has only one collections officer per product family Acceptable: Either stay in 3NF with a waiver naming the accepted anomaly, or record the dependency as a data rule with `enforcement: application` or `dq-check`

Builds on

Explains dependency preservationK-564 · Knowledge

Needed by

None