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ORM and FCIOM

Last post Mon, May 25 2015 14:07 by berhanu seyoum. 2 replies.
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  • Sun, May 24 2015 23:15

    ORM and FCIOM

     Hello,

    thank you so much for taking the time in answering my questions(!) 

    I read in this article (Weber and Zhang,1996) that NIAM had a construct overload, has this been addressed in ORM2?

     Weber, R. and Zhang, Y. (1996). An analytical evaluation of NIAM'S grammar for conceptual schema diagrams. Information Systems Journal, 6(2), pp.147-170. 

    because again I read in Guido Bakema's , H., J.P.C. Zwart and van der Leek's publication( http://www.fco-im.nl/pdfFiles/FullyCommunicationOrientedNIAM.pdf)

    that they want to implement  Redundancy free modeling principle:

    An IG models the user communication about the UoD in a redundancy free way.

    Each aspect of the communication about the UoD may appear only once in an IG.

    These principles imply that an information grammar (IG) should model the structure of the fact stating user sentence types also (at least for elementary facts) and in a redundancy free way. The main aspect of our work is an attempt to incorporate these principles in NIAM in a consistent way, because we felt strongly that in traditional NIAM (Nijssen & Halpin, 1989) these principles had not been carried through completely. 

    If so, please point me to a publication or article or any explanation is also good

    best regards,

    berhanu 

  • Mon, May 25 2015 1:06 In reply to

    Re: ORM and FCIOM

    Hi Berhanu

    Regarding the 1996 paper by Weber and Zhang, I disagree with some of the claims made in that paper, and not see "construct overload" as a problem for NIAM or ORM.

    It is not uncommon for people to argue that NIAM and ORM are too expressive in their graphical notations, but I believe it is very convenient for modelers to visualize a rich array of constraints that apply to real world businesses that are to be modeled in an information system. 

    Regarding the 1994 paper by Bakema, Zwart and van der Lek, both NIAM and ORM require redundancy-free modeling. FCO-IM is different from ORM in a number of ways, e.g. it treats an entity as an objectification of a fact. For example, in their paper they model a room as an objectification of a relationship between a floor (itself an objectification of a unary fact played by a floor number) and a room number. I personally find this unintuitive, but you can make up your own mind in this regard. Moreover, I believe this approach is awkward when dealing with issues such as multiple inheritance, context-dependent reference schemes, and changes to reference schemes resulting from schema evolution. However, I expect that FCO-IM users might disagree with me in this regard. NIAM, ORM and FCO-IM all agree with the basic principles of fact-based modeling.

    Cheers

    Terry 


  • Mon, May 25 2015 14:07 In reply to

    Re: ORM and FCIOM

     Dear Prof. Terry,

    I thought so too,( regarding the paper by Weber et al,) I just wanted to get your take on it. The first thing you check in the model being that you do not have multiple entities representing the same thing. I fail to see that either.

    As for ORM and NIAM being " expensive" I can  understand. But my uncle used to say to me when I was young " Berhanu do not hurry to make a mistake" The rich array of constarints is where one can avoid making a requirement engineering ambiguity. Personally,  I think and believe that, the  way to pursue excellence in modeling is open . Thank you for showing the way and making it simpler. 

    I did use FCIOM, in school ,about 12 years ago,( in the Netherlands actually). I also did some projects. (But I want to stop there)

    Please allow me to say "thank you again" for the rich set of academic research materials, books, publication that you have made availlable. And thank you for the humble spirit that you showed in  taking  time to answer my questions and teach me. This is more than enough for any one to ask. It is a great group that is behind this amazing tool.

    best regrds,

    berhanu 

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