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  • Re: What is a fact?

    &nbsp;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.&nbsp; Your phylogenetics example reminds ...
    Posted to Philosophy (Forum) by Terry Halpin on Wed, Mar 26 2014
  • Re: Spanning Role Value Constraint

    &nbsp;Currently, role value constraints apply only to single roles. Objectification can be a solution in some cases, but is not advisable in your example since there is no uniqueness constraint over the (A,B) role pair. If you have a real world example where you wish to apply a value constraint matching the pattern you show, please provide it and ...
    Posted to ORM Techniques (Forum) by Terry Halpin on Wed, Mar 26 2014
  • Re: What is a fact?

    &nbsp;I basically agree with Niels on how to conceive of propositions. In philosophy, there are different schools of thought on the precise nature of propositions, but I subscribe to one of the more popular viewpoints that treats propositions as extra-linguistic entities that are are always true or false (and hence truth-bearers). Their truth or ...
    Posted to Philosophy (Forum) by Terry Halpin on Tue, Mar 25 2014
  • Re: Exclusion constraints

    &nbsp;Hi Niels &nbsp;If a person can work only once for a given organization, then you can objectify &quot;Person worked for Organization&quot; as Employment and attach functional fact types to it for valid and transaction start and end dates.&nbsp; &nbsp; If a person can work multiple periods for the same organization (e.g. resign, then rehire ...
    Posted to Extensions to ORM (Forum) by Terry Halpin on Mon, Mar 17 2014
  • Re: Exclusion constraints

    Hi Niels I use &quot;period&quot; to mean an anchored duration of time. In the example I gave, periods were closed (anchored at both start and end), so had start and end times (includes date and time of day). If we modify the example to open periods (e.g. each period has a start but in not necessarily an end) the modeling (including constraints) ...
    Posted to Extensions to ORM (Forum) by Terry Halpin on Mon, Mar 17 2014
  • Re: Exclusion constraints

    &nbsp;Hi Niels &nbsp;We are considering support of structured datatypes, that would be modeled explicitly as coreferenced types to facilitate easy conceptual access to their components. An example would be ComplexNumber defined using two relationships to one-dimensional numbers (one for the real part and one for the imaginary part). Conceptually, ...
    Posted to Extensions to ORM (Forum) by Terry Halpin on Sun, Mar 16 2014
  • Re: Exclusion constraints

    &nbsp;NORMA doesn&#39;t yet provide graphical support for those two constraints. Nor does it directly support a temporal range data type. As discussed below, there are multiple ways (I show two ways) to model the basic scenario, but currently those constraints need to be added as textual constraints and implemented manually.&nbsp; We added ...
    Posted to Extensions to ORM (Forum) by Terry Halpin on Sun, Mar 16 2014
  • Re: Question on BBB exercise 3.3

    J is not a conjunction of facts (unlike &quot;Brisbane and Sydney are in some Country&quot; which may be rephrased as a conjunction of &quot;Brisbane is in some Country&quot; and &quot;Sydney is in some Country&quot;. It simply means &quot;Brisbane is in the same country as Sydney&quot; -- you can&#39;t split this into two facts without loss of ...
    Posted to User experience (Forum) by Terry Halpin on Sun, Oct 13 2013
  • Re: Value comparison constraints?

    Hi Clifford, we do plan to implement value comparison constraints, using the graphical notation shown in the &quot;Big Brown Book&quot;, but do not yet have a definite date for that. The precise form of the verbalization for cases like yours is yet to be finalized.
    Posted to Open Discussion & Feature Requests (Forum) by Terry Halpin on Thu, Aug 22 2013
  • Re: NORMA | displaying sample population in orm diagram

    Hi Karl Currently, the only way to display sample data on the diagram would be to include the sample data in Note boxes, which you can place next to the relevant fact types and object types. You can also overlay Sample Population Editor windows on the diagram window, but this would be awkward if you want to view the population of several ...
    Posted to Open Discussion & Feature Requests (Forum) by Terry Halpin on Sat, Aug 10 2013
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