Free practice · matching · hard
Practice
Match grain mistakes to their risks
Match each mistake to the most direct analytical risk.
Order extract · structure card
One row per order, with every field assigned a role
- Observation
- One completed or open order
- Candidate key
- order_id · complete and unique
- Measure
- revenue · quantitative · USD
- Dimensions
- order_date, region, refunded
The row grain and candidate key must be verified before revenue is summarized or tables are joined.