Recognises a functional dependency lost in a decomposition
After a split, a dependency spans two entities and no key in either one enforces it. Typical after a BCNF split (row 11).
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What it looks like in practice
Expected result: The dependency that now spans two entities and that no key enforces
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
Also known as: Dependency lost in decomposition (logical model)
Related knobits
Builds on
All 56 knobits of Derive the logical data model.
Source: Review checklist 05-logical, row 15; Rissanen 1977; E&N ch. 15