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  • Re: Exclusion constraints

    Hello Clifford, Forgive me my ignorance. I wasn&#39;t even aware of the existence of two separate versions of NORMA. Frankly, I am not necessarily enamoured with graphical notation only, so I don&#39;t necessarily care so much about a tool, as much as about the modelling language itself (its axioms, theorems etc.). My experience with ...
    Posted to Extensions to ORM (Forum) by Niels Hoogeveen on Sun, Mar 16 2014
  • Re: Exclusion constraints

    &nbsp;Hi Ken, The model as it is now, comes much closer to the specification we started with, however it is not exactly what I was trying to accomplish. A great model should in principle be able to express all that is needed to derive the desired implementation. Whether that derivation is algorithmically implemented in a tool is a different ...
    Posted to Extensions to ORM (Forum) by Niels Hoogeveen on Sun, Mar 16 2014
  • Re: Exclusion constraints

    Hello Ken, Thank you for your example. I greatly appreciate the effort you put into answering my question. Let me start with a practical note: I get &quot;Access denied. You do not have permissions to perform the requested action&quot;, when trying to download the files you created (I was logged on when trying to download).&nbsp; Now to the ...
    Posted to Extensions to ORM (Forum) by Niels Hoogeveen on Sun, Mar 16 2014
  • Re: Exclusion constraints

    &nbsp;Hello Ken I am looking forward to see what you are brewing, and thanks for the information about VS.&nbsp; Niels&nbsp; &nbsp;
    Posted to Extensions to ORM (Forum) by Niels Hoogeveen on Sat, Mar 15 2014
  • Re: Exclusion constraints

    Hello Ken, Thank you for your quick response to my question. Back in the 1990s, I worked for a company where we used Infomodeller for our database design, and I very much liked the approach. Ever since I have used the schema techniques on a more informal basis (white board drawing, pen and paper design), but haven&#39;t yet caught up with the ...
    Posted to Extensions to ORM (Forum) by Niels Hoogeveen on Sat, Mar 15 2014
  • Exclusion constraints

    Postgresql since version 9.0, supports the notion of&nbsp;exclusion constraints, which are a generalization of uniqueness constraints. Exclusion constraints are particularly helpful when dealing with datatypes like ranges, where equality is not necessarily the most helpful operator.&nbsp; With exclusion constraints one can state that a certain ...
    Posted to Extensions to ORM (Forum) by Niels Hoogeveen on Fri, Mar 14 2014
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