Re: XML Schema as a data modeling tool

I do not understand. Here comes my view.

(a) A system is a set of entities, which are concepts.
(b) In isolation, these concepts (say, customer, bookings, accommodations) are best modelled as trees, as all stakeholders understand them immediately and comprehensively, regardless of their background
(c) The fact that these trees reference each other suddenly implies that we should cancel our tree models which served us so well.

Why? And what shall replace point (b)?

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Von: Peter Hunsberger <peter.hunsberger@gmail.com>
An: Hans-Juergen Rennau <hrennau@yahoo.de>
CC: Michael Kay <mike@s...>; "xml-dev@l..." <xml-dev@l...>
Gesendet: 23:14 Montag, 30.September 2013
Betreff: Re: XML Schema as a data modeling tool

We may very well be aiming at different scales.  However, in my experience any set of entities that can be described a single concise hierarchy isn't going to require much management  buy in and as such using XSD for domain management isn't going to revolutionize the world of software development any time soon.  At any reasonable level of complexity -- one that does require management buy in-- hierarchies in the shape of trees become forests and binding them all together requires the modelling equivalent of ID/IDREF.  At that point you've got models that have cross references that must be manually looked up and traversed and you've reinvented the worst possible form of a graph for managing the complexity.

Peter Hunsberger