6. etapp: Füüsilise andmemudeli kujundamine
Kompetentsi Andmete modelleerimine knobit · K-655 · Teadmine
Explains null semantics and three-valued logic
Mida see tähendab
What a null means, and how predicates evaluate to UNKNOWN.
Kuidas seda hinnatakse
Predicts how sample predicates treat nulls
Tugineb
- Puudub
Vajalik
- Recognises nulls left to chance in a check predicateK-714 · Oskus
- Recognises a default inventing a business factK-820 · Oskus
- Recognises a sentinel value standing in for nullK-629 · Oskus
- Recognises a null with a business meaningK-630 · Oskus