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Hi Eric
Thanks for your query. Just right-click anywhere on the document window, and choose Extension Manager. In the Extension Manager dialog, select the "Map to Abstraction Model" check box (this will automatically turn on the "Map to Relatonal View" option). If you want to see the relational schema ...
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This is a response to both Ken and Sjir's previous responses.
First, Ken, your new model now has the subset constraint on the correct arguments but it is pointed in the wrong direction (assuming we agree that a habitation may have a start date without necessarily having an end date).
Second, Ken's model includes a uniqueness ...
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Hi Ken
Thanks for your model, which does correctly identify two ternaries that are derivable from the original example. However, your model has some problems. As a trivial error, the subset constraint in your model is wrong (it should go between the person-country role-pairs). But the main problem is that it assumes COMPLETE ...
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As yet another solution to the habitation example, we could use the quaternary "Person lived in Country from Date to Date" for cases where the end date is known, and run a subset constraint from the sequence of its first three roles to the ternary "Person began a habitation in Country on Date". This would ...
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Dear Sjir
Your example is an interesting one, and does illustrate a difference between ORM and CogNIAM. In CogNIAM, I take it that you treat a fact type such as
Person lived in Country from Date to Date
as an asserted fact type, allowing that the end date is optional, which means that you allow nulls in asserted fact instances. For ...
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ORM, CogNIAM and SBVR are all fact-oriented approaches, and it is possible to define a common core metamodel based on an intersection of these approaches, and hence enable translation between useful subsets of them. ORM and CogNIAM have much in common, and the difference between them is not so much one of formality (as both can be given a ...
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Thanks for setting up the literature forum.
The second edition of Information Modeling and Relational Databases was released March 3 in the US, and is currently available there, but I'm told that it won't be available in Europe until around April 11.
The publishers's online website for the book is still being set up, but will contain ...
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Currently NORMA requires at least the standard version of VS2005 or VS2008. We are hoping that the free VS2008 shell will be extended with a module that would allow NORMA to run with that, but we are still waiting on a decision in this regard.
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Unfortunately the fact editor has had little done to it since Scott graduated from Neumont.
We are currently focusing most of our efforts on rearchitecting the transformation process from ORM to allow live views of target structures (e.g. database schemas and class models) and to enable much better handling of data types and name generation. ...
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Hi Clifford
Your claim that ''unique and mandatory constraints are just instances of frequency constraint'' is only party true. You may treat a uniqueness constraint as a frequency constraint of 1, but a mandatory constraint cannot be reduced to a frequency constraint. A frequency constraint of n on a role says that any instance playing that ...