The ORM Foundation

Hi,

In NORMA (June 2007 a), setting the "ExpandRefMode" property, for an Entity Object Type with a Reference Mode/Scheme, to "True" has the expected result of displaying the compact version of Item(ModNum), as Item has ModNum, with a UC over each role in the FactType, with a MRC for Item's role.  That's fine.

If You select a value object type, the properties window still offers a "ExpandRefMod."  I can't see why this is a property for a VOT.  Out of curiousity, I switched one from the default "False" to "True" but the is no apparent result for doing so.

BRN..

You do have a point, which could also be extended to say that the property should not be offered if there is no reference mode.

On the other hand, to extend your scenario, if you now set 'IsValueType' to False, the RefMode property will appear and you can set the RefMode property, which will then appear in expanded form. Basically, ExpandRefMode is a property on the ObjectTypeShape element that says 'If the ObjectType I'm associated with does have a RefMode, should the pattern be collapsed?'. This is a moot point if you're currently a value type, but a value type can easily morph into an ObjectType with a ref mode.

For kicks, enter 'A has B()' in the Fact Editor (or 'A has/is of B()' in the new fact editor). Now select the value type role and a uniqueness constraint. Select the new constraint and set its IsPreferredIdentifier property True. If you select A, you'll see that ExpandRefMode is now true.

-Matt

Hi Matt,

This looks like one of those things where the requirements of a working application impose themselves on the methodology and theory.  I sometimes think of the tool as like a butler: there to carry out the wishes of his master, but with the limitations of any human being.  As the tool architect, do you ever feel a bit like that yourself?  "Very good sir; but may I inquire if the master has any ideas as to how I might carry out the master's wishes - given that they seem to run contrary to the immutable laws of physics?"  "Quickly and quietly?; as you say sir. Thank you sir.  I'll see to immediately.  If there's nothing else, I'll leave you to your breakfast sir; and again I apologize for the excessive yellowness of the egg yokes - I'll have a word with the hens sir."  BRN..