Re: What is ur-definition ?

OK, that's been FAQ'd -
http://www.schemaValid.com/faq/xml-schema.html#c6

Noah_Mendelsohn@lotus.com wrote:
> 
> >> Hi:
> 
> >> Could some of the members of the mailing list share views
> >> on what is a ur-definition ? what is the rationale behind it
> >> and why it is called so ?
> 
> >> Thanks in advance.
> 
> >> best regards
> >> Dev.
> 
> Dear Mr. or Ms. Dev,
> 
> >From [1] in the specification:
> 
> "[Definition:]  A distinguished ur-type definition is present in each XML
> Schema, serving as the root of the type definition hierarchy for that
> schema. The ur-type definition, whose name is anyType, has the unique
> characteristic that it can function as a complex or a simple type
> definition, according to context. Specifically, restrictions of the
> ur-type definition can themselves be either simple or complex type
> definitions."
> 
> I think that says it, the ur-type is the root of the type hierarchy in
> each schema.  It's like "object" in Java, everything derives from it.  As
> to the name, I don't speak German, but I believe ur is an abbreviation for
> über", which I believe translates as "above" or upper, and is commonly
> used as a prefix adjective.  So, ur-type is approximately supertype or
> root type.  I personally would not have gone for such an obscure name,
> but....  Anyway, the actual string name you use for it in a schema
> document is "anyType".  e.g.
> 
>         <xs:element name="envelope"  type="xs:anyType"/>
> 
> The manifestation of the urType that admits only simple types is
> anySimpleType:
> 
>         <xs:attribute name="thisAttrCanHoldAnyString"
> type="xs:anySimpleType"/>
> 
> The term urType shows up only when you read the specification itself
> (historically we called it the urType, then added the convenience name,
> and decided not to change the whole rest of the spec.  Users see "anyType"
> and "anySimpleType".)  There are some subtleties in the type hierarchy,
> but the above should get you through 99%+ of what you need to do.  Hope
> this helps.
> 
> [1] http://www.w3.org/TR/xmlschema-1/#key-urType
> 
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