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  • Re: ORM to UML

     The workaround I use is to create a class for the attribute. For the example on p. 404, create a class called PersonTitle and give it an attribute called "value" or "text" to record the actual title, and add another attribute called "restrictedGender" then add a textual constraint (e.g. in OCL) to capture the ...
    Posted to Technical support (Forum) by Terry Halpin on Sat, Apr 18 2015
  • Re: Generate Class Diagram in UML

     Currently, NORMA doesn't generate UML class diagrams from an ORM model. This is something we'd like to support in the future. For a basic procedure on how to manually map ORM to UML, see section 9.8 of Information Modeling and Relational Databases, 2nd edition.   To copy an ORM diagram to the clipboard, right-click an empty ...
    Posted to Technical support (Forum) by Terry Halpin on Wed, Apr 15 2015
  • Re: Implicit disjunctive mandatory constraint

     Hi Matt  Your initial statement of your new understanding of  implicit disjunctive mandatory role constraints is basically accurate. As a fine point, we now say that an object type "hosts" a role, whereas an object instance "plays" a role.  Regarding your first follow-up question, the role hosted by Study ...
    Posted to ORM Techniques (Forum) by Terry Halpin on Wed, Apr 1 2015
  • Re: Implicit disjunctive mandatory constraint

     Hi Matt (Nizol) Matt Curland's response is quite correct and should clarify the issue for you.  Please note however, that the BBB does not claim that elementary fact roles are mandatory for a primitive entity type. The p. 161 reference you mentioned includes the following condition "unless declared independent". Also, ...
    Posted to ORM Techniques (Forum) by Terry Halpin on Wed, Apr 1 2015
  • Re: Transitive implication in a subtype graph

     Subtyping in ORM is always direct subtyping, not indirect subtyping. Direct subtyping is strongly intransitive, so transitively implied subtyping relationships should not be asserted.   Cheers Terry 
    Posted to NORMA (Forum) by Terry Halpin on Sat, Mar 28 2015
  • Re: Model elements that are not displayed on any diagram

     NORMA allows an ORM schema to be displayed on many pages. The same model element may be displayed on many pages. It can be convenient to remove some shapes from a page to better focus that page on a specific subarea of the overall schema. There's probably little practical value in removing the final shape of a model element if you want ...
    Posted to NORMA (Forum) by Terry Halpin on Wed, Mar 11 2015
  • Re: Role value constraints in ORM2

     Yes, that's correct. I added role value constraints to ORM 2 in the mid 1990s. Before that, they applied only to object types. Cheers Terry 
    Posted to ORM Techniques (Forum) by Terry Halpin on Tue, Aug 12 2014
  • Re: What is a fact?

    Hi Ken Although I am not a fully fledged Platonist, I could be classified as one kind of realist, as the term is currently used in philosophy. Your quote from Russell (1920) where he treated a proposition simply as a declarative sentence represents a position that few philosophers (other than Epstein, apparently) would agree with nowadays. ...
    Posted to Philosophy (Forum) by Terry Halpin on Fri, Mar 28 2014
  • Re: What is a fact?

    Hi Ken Sentences are linguistic, but propositions are not. Utterances are speech acts, not propositions. A proposition is what it is that is asserted when a declarative sentence is uttered or inscribed. Of course, to determine the precise proposition expressed by an utterance or inscription of a sentence, one has to know the relevant context of ...
    Posted to Philosophy (Forum) by Terry Halpin on Thu, Mar 27 2014
  • Re: What is a fact?

     Hi Niels You are probably aware that communication act theory (formerly, and sometimes still, known as speech act theory) has been an active field of study for many years, with Austin and Searle being the main early contributors. For a concise overview, see http://en.wikipedia.org/wiki/Speech_act.  Your phylogenetics example reminds ...
    Posted to Philosophy (Forum) by Terry Halpin on Wed, Mar 26 2014
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