RE: What is a namespace ... really?
Roger Costello wrote: > James Tauber wrote: > > >>(2) A namespace is a URI to a DTD. > > > >No. It doesn't have to be at all (although it *could* be and a URI > for a > DTD > >is as good a URI as any and better than most) > > What good is a namespace if it *doesn't* reference a DTD? > [Ron Daniel] The advantage is namespace scoping, along the lines of Java packages. But let me give an XML-based example. Assume you have gotten 2 XML documents, from different sources, and they both contain the element <title>. How do you know if they mean the same thing? One might be a book title, the other might be a job title. (Or a royal title or a legal title to property or a championship title or ...). But, if one says <dc:title> and another says <aba:title> (and you look up the URIs and see they are different - one for the Dublin Core group and the other from the American Bar Association), then you can tell that they are not the same use of <title> and you should treat them differently. Namespaces allow us to prevent name collisions. This is very good. Now, the next thing to do is have the namespace URI point to something like a DTD, and there are lots of us who want to do such things. But that is outside the narrow bounds of the current spec. While I wish the spec had gone on to deal with parts of that topic, I also have to say that unique names are nothing to sneeze at, and are a valuable step forward. Regards, Ron Daniel Jr. DATAFUSION, Inc. 139 Townsend Street, Ste. 100 San Francisco, CA 94107 415.222.0100 fax 415.222.0150 rdaniel@d... http://www.datafusion.net > xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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