[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Question for updating existing XML file
Michael Kay scripsit: > XML has a clear story on hierarchical relationships, but a very confused > story on those that aren't hierarchical. There are lots of ways of doing it: > URIs, IDREFs, XLinks, or just "unmarked" foreign keys. None of these is > clearly definitive. Only one of these (ID/IDREF) actually belongs to the model. The rest belong to higher-level protocols, which could just as well be layered on the relational model as the XML model. > There are probably two design decisions in XML that are really hard to make > correctly, yet very hard to change later. One is "what goes in a document?", > the other is "which relationships should be represented as parent-child > relationships?". XML was designed to model documents, which are the most complex form of data, and where the answers to these questions are evident. Probably if the answer isn't evident for a particular job of modeling simpler data, you shouldn't use these features except in stereotyped ways. See Henry Thompson's paper on various normal forms of XML. -- John Cowan cowan@c... www.reutershealth.com www.ccil.org/~cowan Heckler: "Go on, Al, tell 'em all you know. It won't take long." Al Smith: "I'll tell 'em all we *both* know. It won't take any longer."
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