On 06/03/2012 02:27, David Lee wrote:
I've been contemplating the relationship between schema and type in schema
aware xquery.
Is xquery strictly tied to XSD? That is, could an implementation support
another schema format such as rng to provide for the type system?
It would be possible to support a different schema language, but not
without difficulty.
(a) XSD is the only schema language I know of that defines how elements
and attributes in the instance document are associated with types, and
that includes constraints (such as the notorious UPA) to make this
association unambiguous.
(b) Many of the concepts of XSD, such as the distinction between simple
and complex types, substitution groups, and nullability, turn up in the
semantics of XQuery, and would need to be mapped to the concepts of a
different schema language.
Michael Kay
Saxonica
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