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Cyclic Reference in GovernmentalServices.xsd

Katharina SCHLEIDT
By Katharina SCHLEIDT Replies (2)


I'm currently working on a simple extension to the GovernmentalServiceType; while trying to chase down a bug in my extension schema I saved a local copy of GovernmentalServices.xsd and got an error that all types are already declared.

In the process of chasing this down I noticed that there's a cyclic reference:

  • GovernmentalServices.xsd includes UtilityNetworksCommon.xsd
  • UtilityNetworksCommon.xsd includes GovernmentalServices.xsd

To my memory this isn't legal (but maybe there are better brains out there who know that it is). It does make XMLSpy unhappy, so probably other tools are also suffering.

Anybody else run into this yet? Ideas/Thoughts?



  • Angel LOPEZ ALOS

    By Angel LOPEZ ALOS

    Hi Katharina,

    Thanks for pointing this out.  I consider that you are completely right and most probably other tools will also suffer. Nevertheless the domain scope of the references is a relevant added value in the model that should not be removed whenever possible.

    It would be interesting to get some ideas from experts about how this cyclic reference could be broken when keeping the scope. Probaly this problem has been already addressed by other themes so it would be good to share the questions with other clusters/themes. 

    Please, let me know if you want me to do it on your behalf.




  • Katharina SCHLEIDT

    By Katharina SCHLEIDT

    Hi Angel,

    my Spy problems actually turned out to be elsewhere, so not sure if these cyclic references really are a problem or if I'm just too careful (seems like it should cause a problem! ;) )

    While thinking on possible solutions I came to the conclusion that such cyclic references are unavoidable the moment we have bidirectional references; to avoid such cycles we'd need a directed graph, which doesn't work with bidirectional references.

    But, it again underscores one of my current pet peeves that we'd really need a cross-theme technical cluster to deal with this type of issues (one of the initial triggers for this was the topic:

    Back to the cyclic references - think this is the least of our worries for the present, but good if a few of us have it at the back of our minds in case it does become a problem



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