I am just now starting to see the value in these names, especially after discovering one of them yesterday that is actually an Internet key word with thousands of inquiries thru a key word service suggestion tool. Don’t pass them up if you find one.
Value domains are the collections of values which may be assumed by a Normal Attribute. Sometimes these may be context-dependent, which may lead to the separation of sub-domains.
Value Sub-Domains arise because there are many attributes, that, while they mean or refer to different things, draw their values from the same source.