Task by Task · Free local practice
Give AI a data dictionary before it combines your files
Fictional invoice and customer files. This example runs locally; files selected here stay in browser memory.
Protect field meaning before a join
- Customer IDs are text with leading zeros
- Amounts are pence
- Open rows only; unique customer keys
001 is not automatically 1. Duplicate lookup keys or unmatched IDs need an explicit rule before totals.
Take the technique to your next job
Before combining these supplied files, use this data dictionary:
[field meaning, type, unit, grain, key and missing convention].
Confirm the intended join and scope. Preserve text identifiers including
leading zeros, valid numeric zero and explicit missing values.
Check required key uniqueness and unmatched records. Do not infer units,
aggregate grain or duplicate policy from column names. Ask a focused
question for any definition needed before the calculation can be valid.