Domain Modeling

Purpose

Make the code speak the business's language precisely. Most long-lived complexity comes from a mismatch between the words the business uses and the structures the code has — where "user" means four different things and none of them are named.

When to Use

• The same concept has different names in code, in the database, and in conversation.
• A single model class is used by three subsystems that each need something different from it.
• New requirements consistently require changes in unrelated modules.
• Designing a new subsystem in a domain with real business rules.

Capabilities