When it comes to data quality in large enterprise organizations, what's essential is that the rules be formally documented (before development begins).

For example:

- If Col1 = 'A' then Col2 must be 1, 2, or 3.

- When Col3 is updated, then Col4 must also be updated with Date+Time EST.

The documentation must be continuously revised post-production as the business rules change, be published so that any user who queries the database has access to them, and be endorsed and promoted by mangement.