Stage 6: Design the physical data model
Knobit of Data modelling · K-655 · Knowledge
Explains null semantics and three-valued logic
What it means
What a null means, and how predicates evaluate to UNKNOWN.
How it is assessed
Predicts how sample predicates treat nulls
Builds on
- None
Needed by
- Recognises nulls left to chance in a check predicateK-714 · Skill
- Recognises a default inventing a business factK-820 · Skill
- Recognises a sentinel value standing in for nullK-629 · Skill
- Recognises a null with a business meaningK-630 · Skill