Reference data is database data that must be prepopulated for an application to operate properly and cannot be modified by that application. It belongs to the database schema alongside tables, views, indexes, and stored procedures. section 10.1
User types in a CRM system
A UserType table containing Customer and Employee values is reference data when users depend on those rows through a foreign key. The application relies on the values but does not modify them. section 10.1
Manage reference data as part of database delivery:
- Store it in source control with the rest of the database schema. section 10.1
- Apply every change through explicit migrations rather than treating the data as disposable test data. section 10.7
- When resetting integration tests, delete regular data but preserve reference data; let migrations control it. section 10.3
