# Changes to Schema Processing

Element values participating in uniqueness or key/keyref constraints may now contain embedded comments and/or processing instructions.

Elements and attributes participating in uniqueness or key/keyref constraints may now contain namespace-sensitive values (xs:QName and xs:NOTATION).

The type of elements and attributes participating in uniqueness or key/keyref constraints may now be a list or union type. (Previously list types were allowed under restricted circumstances.)

The fixed value of an element or attribute may now be a namespace-sensitive value such as an xs:QName or xs:NOTATION. The default value may alse be namespace-sensitive; however, the default value will be rejected unless the namespace prefix it uses is in scope in the source document, and bound to the correct URI. (The schema specification is unclear on this point, but this seems to be the only reasonable interpretation.)

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