Basic XMLSchema questions

Henry S. Thompson ht at cogsci.ed.ac.uk
Wed Jan 5 23:37:01 GMT 2000


Brett McLaughlin <bmclaugh at algx.net> writes:

> Alan Santos wrote:
> > 
> > Hi,
> >  I'm trying to wrap my head around the XMLSchema drafts to determine their
> > immediate usefulness (to myself), and have some very basic questions.
> > 
> > 1)  What is the difference between an archetype, type and datatype?
> > When is one used in place of the other.
> 
> <archetype> is gone, replaced by <type>, which is used for specifying
> non-"primitive" (i.e. predefined) types for elements.
> 
> <datatype> is for doing the same sort of operation on attributes.
> 
> for example:
> 
> <element name="myElement">
>   <type>
>     <element name="nestedElement" type="string" />
>     <element name="anotherNestedElement" type="string" />
>     <attribute name="isPrimary">
>       <datatype content="empty" />
>     </attribute>
>     <attribute name="focus">
>       <datatype content="NMTOKENS">
>         <enumeration value="Java" />
>         <enumeration value="C" />
>         <enumeration value="XML" />
>       </datatype>
>     </attribute>
>   </type>
> </element>

The spirit of the above is entirely correct, there are a few mistakes
in the details.  For the overall story, see my reply to the original
post.

The example above is not quite schema-valid, as follows:

> <element name="myElement">
>   <type>
>     <element name="nestedElement" type="string" />
>     <element name="anotherNestedElement" type="string" />
>     <attribute name="isPrimary">
>       <datatype content="empty" />
                  ^^^^^^^
         not allowed on <datatype>, I guess you want something like
         <attribute name="isPrimary" type="boolean"/>
>     </attribute>
>     <attribute name="focus">
>       <datatype content="NMTOKENS">
                  ^^^^^^^
         again, not quite right, I think you mean source="NMTOKEN"
>         <enumeration value="Java" />
>         <enumeration value="C" />
>         <enumeration value="XML" />
>       </datatype>
>     </attribute>
>   </type>
> </element>

Not surprisingly, I'm more positive about the utility of type
derivation than you are :-).

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht at cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/

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