In ERwin, you can define domains or use system-defined domains. Each domain has properties that you can apply to one or more columns. You can use domains to reuse a given set of properties for multiple columns.

In ERwin, domains have hierarchies. The system-defined domains are the top-level domains of the hierarchy. You can create sub-levels in the domain hierarchy by creating user-defined domains.

You can also apply validation rules to domains in ERwin.