The ORM Foundation

In "Temporal Modeling: Part 4," Terry Halpin discusses using rigid subtypes in ORM and provides some examples (e.g., in figures 3, 4, and 7). Is there any way of identifying/portraying rigid subtypes in NORMA, even though rigidity is a dynamic constraint?

Hi Richard,

Sorry, but at the moment we have no way of marking either a fact type or a subtype as rigid. We plan on adding this support in the future, but it is not very high on the priority list right now.

 -Matt

Hi Clifford,

We haven't locked anything down at this point, but it will likely be similar to what Terry shows in his book (brackets or bold vertical lines at the edges of the fact type and on the text of the object type). I'd probably do something that doesn't look exactly like a character (brackets have other meanings as well).

So, no, I can't give you a graphical representation at this point because I haven't mocked it up or given it extensive thought. 

-Matt