Knobit of Data modelling · K-820 · Skill

Recognises a default inventing a business fact

What it means

A `DEFAULT` on a business column rather than a technical one. `CURRENT_DATE` on a value date fabricates a date when the feed omits one; `0` on an amount turns "unknown" into "zero", and the zero then sums into a total that reconciles; `'OPN'` on a status decides a business state on the loader's behalf.

How it is assessed

Flags the deficient case and passes the acceptable one. Deficient: `settled_amount DECIMAL(14,2) DEFAULT 0`: unsettled payments arrive as zero, the settlement total reconciles to the cent, and the missing settlements are invisible in exactly the figure someone reports Acceptable: `settled_amount` nullable with no default and a completeness DQ rule over the payments that should have settled. Defaults only on `created_at`/`updated_at` and on identity columns — and note the generator rejects a column that declares both `identity: true` and a `default`

Builds on

Recognises a sentinel value standing in for nullK-629 · Skill
Explains null semantics and three-valued logicK-655 · Knowledge

Needed by

None