What is the purpose of a reference dimension in a data model?

• A. To store static code mappings for lookups
• B. To store transaction facts
• C. To store user credentials
• D. To log errors

Answer: (A)

Reference dimensions provide stable codes and their descriptive attributes used for lookups across the data model. They centralize code-to-description mappings (like country codes to names or product category codes to categories) so fact tables can join to a consistent, descriptive set of attributes. This enables conformed dimensions and reliable filtering and labeling in reports. They’re not intended to store transactional measures, user credentials, or error logs—those belong in fact data, security systems, or logging systems. So the purpose is to store static code mappings for lookups.