The ORM Foundation

Just my limited experience, but I've never heard of constraints on a derrived fact type. I would expect that the derrivation rule itself would provide all the constraints necessary. If you're running into problems with derrivation rules, it probably means there are facts about the UoD that are not being stored. Let me try an example to argue ...

Thanks, I think you understand what I am trying to model. Your proposal works and I believe it is the same as the second option I proposed. I still am just a little bit troubled by it, more from a theoretical than from a practical point of view. The fact ''LocalTeam(Name) is of School'' (or ''SCHOOL(name) manages TEAM(id)”) doesn't add new ...

Hi, Sometimes it a bit hard to understand what a person is trying to model, when they start in with methodology specific assertions, rather than the basic facts that they are trying to model - we'll I find it hard, anyway. The basic facts for your model might be stated: A school enrolls students A given student is enrolled in at ...

If… SCHOOL(name) enrolls STUDENT(id) STUDENT(id) plays on TEAM(id) …then what kind of constraint should I create to ensure that a team only includes students from a single school? One option is to create a derived fact “SCHOOL(name) enrolls some student who plays on TEAM(id)”, and then put a ...

Thanks for the reply, For now I'm going to the diagram and selecting an Object (Object, Role, Constraint...), and using that to find the approx place in the OB - sort of object browsing in reverse. Yes, the new OB will be very welcome. BTW, what kind of scale/dimension are you testing with the current release? I'd like to know what you folks ...

Hi, Gonna take a little while to digest what you passed along! Thanks for the reply, Matt. There's an apparent subtext in what you said, and that is there's a great deal of cooking going on in great many pots - to paraphrase a line from John LeCarre's ''A Spy who Came in From the Cold.'' I hope you and others will post more ''heads up'' ...

The current model browser has a number limitations, and we are putting very few cycles into addressing them because we are actively working on a new, much more flexible browser. A few of the major issues: 1) Performance. The performance is dreadful as the models get larger. If you see even small changes getting sluggish (for example, ...

The NORMA designer is a highly extensible system based on the Microsoft DSLTools framework, enhanced with a number of our own extension points to allow multiple models, multiple diagrams, etc. In fact, the main distinction between the two default models (the core model and the shape model) lie in the fact that you can't turn off these two main ...

Hi, A recurring point of frustration is in having to manually change role names, to avoid mapping errors when generating DDL scripts. A common problem concerns ring constraints with a FactType like 'Team(ID) plays Team on Date()' with an asymetric ring constraint to keep a team from playing itself. A solution is to rename the first role to ...

Hi, Openning up the ORM object browser drills doown to a list of object (like constraints), but it's not allways easy to know where the listed object is in the ORM diagram (let alone a multi-page ORM diagram). Seeing 'Internal Uniquness Constraint 17' doesn't give a lot of info about just where in the model diagram IUC is to be found. Any way ...