Stage 6: Design the physical data model, Stage 8: Generate and review DDL
Knobit of Data modelling · K-618 · Skill
Recognises binary floating point used for an exact quantity
What it means
`FLOAT`, `REAL` or `DOUBLE` for money, areas, shares or anything compared for equality or totalled. Totals do not tie and equality tests fail. A specific form of row 17.
How it is assessed
Flags the deficient case and passes the acceptable one. Deficient: `payment_amount FLOAT`: the sum over payments differs from the statement total by cents. `loan_interest_rate REAL`: a repayment schedule rebuilt from it does not reproduce the instalments Acceptable: `NUMERIC(12,2)` for euro amounts, `NUMERIC(9,6)` for interest rates, scale as the business states it; floating point only for quantities that are approximate by nature (a model's risk score)
Builds on
- Explains exact and approximate numeric typesK-654 · Knowledge
Needed by
- None