[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XML Schema question
I came across this while trying to subset WXS and explain the use of the subset and it is partly a curiosity to me but partly it raises questions about what is minimally required for maximum simplicity with maximum utility in a MicroXSD subset: Are these three ways to do exactly the same thing, i.e. defined precisely the same constraints on an XML instance (in this case a single element named 'Greeting' of datatype 'string' <Greeting>Hello World</Greeting>)? 1. <schema xmlns="http://www.w3.org/2001/XMLSchema" attributeFormDefault="unqualified" elementFormDefault="qualified"> <element name="Greeting"> <complexType> <simpleContent> <extension base="string"/> </simpleContent> </complexType> </element> </schema> 2. <schema xmlns="http://www.w3.org/2001/XMLSchema" attributeFormDefault="unqualified" elementFormDefault="qualified"> <element name="Greeting"> <simpleType> <restriction base="string"/> </simpleType> </element> </schema> 3. <schema xmlns="http://www.w3.org/2001/XMLSchema" attributeFormDefault="unqualified" elementFormDefault="qualified"> <element name="Greeting" type="string"/> </schema> I kind of tend to want to remove such redundancy unless there is some value keeping three ways to do the same thing. I guess a processor trying to take of advantage of only having to conform to the conformance target of the subset might prefer to only have to handle one kind of rep- resentation in the markup. I prefer to prune out the attribute 'type' because it introduces complications for my metaschema but I'm inclined to prune away the simpleType as a child of an element and just keep simple type for an attribute. Then a processor need only expect 'complexType' as an element child. Does this make sense? Option 1 seems to give most extensibility so why bother with 2 and 3? Maybe some of the redundancy could have been removed from WXS but I guess it is too late now to make big changes in any future version. Not having to handle multiple namespaces makes a great difference to the pain of explaining the subset - makes me happy about MicroXML. Cheers ---- Stephen D Green On 01/03/2011, Stephen Green <stephengreenubl@gmail.com> wrote: > OK, maybe it is impossible to get it perfect but I updated > the MicroXSD subset of W3C XML Schema and gave it a > version number '2012' - "future-looking", "going-forward" :-) > > I have posted it on my blog > http://stephengreenxml.blogspot.com/2011/02/microxsd.html > > Comments welcome > > ---- > Stephen D Green > > >
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