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  • Re: Question about join constraints and paths

    Nicola, ORM is better: The point about &quot;ORM being better than anything else&quot;&nbsp; is in part related to the fact that NORMA uses RMAP to instantly create a 5NF logical model. This is &quot;better&quot; than alternative methods such as ERM because it saves a great deal of time. This was the subject of my 2007 MSc project which is ...
    Posted to Contributed Models (Forum) by Ken Evans on Fri, Oct 26 2018
  • Relational Mapping Algorithm - is it OK?

    &nbsp;In this separate thread, Nicola said: &quot;I am disappointed (but not surprised) by the ORM-to-Relational mapping performed by NORMA. This is a topic for a different thread, though.&quot; So the purpose of this thread is to discuss Nicola&#39;s concerns about relational mapping in ORM and its RMAP implementation in NORMA. RMAP is ...
    Posted to ORM Techniques (Forum) by Ken Evans on Fri, Oct 26 2018
  • Re: Question about join constraints and paths

    Nicola, &quot;your view of a conceptual model is obviously biased towards a fact-oriented view: not all conceptual models are&quot; In this website, we use the term &quot;conceptual model&quot; within the universe of discourse called &quot;object-role modeling&quot; as defined by Terry Halpin in his 1989 thesis and in many subsequent ...
    Posted to Contributed Models (Forum) by Ken Evans on Fri, Oct 26 2018
  • Re: Question about join constraints and paths

    Inter-predicate role-path editing is not yet implemented in NORMA for VS2017. Yesterday,&nbsp; Terry added some clarification to the role path editing issue. This is the relevant part of what he said.NORMA for VS2017 automatically infers the join path for unambiguous cases (e.g. Figure 10.4 of the &quot;Big Brown Book&quot;, and in your example, ...
    Posted to Contributed Models (Forum) by Ken Evans on Fri, Oct 26 2018
  • Re: Question about join constraints and paths

    &nbsp;Nicola, I posted a question about the Kohler paper in the &quot;database experts&quot; group on LinkedIn. Fabian Pascal confirmed my own view that logical models are not related to physical models.&nbsp; This is what Fabian said;&nbsp; One of the most common and entrenched misconceptions is the logical-physical confusion (LPC) (another ...
    Posted to Contributed Models (Forum) by Ken Evans on Fri, Oct 26 2018
  • Re: Question about join constraints and paths

    &nbsp;&quot;The model is loosely &nbsp;based on an example from Koehler&quot; Kohler gives this example of a relation:&nbsp; R ={Student, Course, Chapter, Time, Room} Whilst this may be true in mathematical terms, it does not contain the ORM concept of using a predicate to define the roles played by each of the &quot;attributes&quot; in the ...
    Posted to Contributed Models (Forum) by Ken Evans on Thu, Oct 25 2018
  • Re: Question about join constraints and paths

    &nbsp;Thanks for the orm file. I think that it would be useful to split this discussion into two separate subjects. (1) &quot;Role paths in NORMA&quot; and (2) &quot;How to design an object-role model&quot;.&nbsp; Inter-predicate role-path editing is not yet implemented in NORMA for VS2017. (2) Designing object-role models You said that your ...
    Posted to Contributed Models (Forum) by Ken Evans on Thu, Oct 25 2018
  • Re: Question about join constraints and paths

    Thanks for posting your updated model.&nbsp; However, it would be helpful if you could post the &quot;equivalent&quot; ORM file, because that would allow people to use the powerful features in NORMA to review your model. .&nbsp;
    Posted to Contributed Models (Forum) by Ken Evans on Thu, Oct 25 2018
  • Re: Question about join constraints and paths

    &nbsp;Nicola, I see that your model is named &quot;Koehler2007s.orm&quot; If this is a reference to a publication, please let me have the reference so that I can follow up. Thanks Ken &nbsp;
    Posted to Contributed Models (Forum) by Ken Evans on Thu, Oct 25 2018
  • Re: Question about join constraints and paths

    The simple answer is &quot;partially&quot;. Since it is Terry&#39;s book, I have asked him to give a response. In the meantime, if you put &quot;join path&quot; in the search box at the top right and select &quot;entire site&quot; , you will see that join paths have been &quot;in discussion&quot; for about ten years. &nbsp;Ken
    Posted to Contributed Models (Forum) by Ken Evans on Thu, Oct 25 2018
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