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Data Descriptors formalize properties of our data.

The sorts of properties which can be expressed involve:

Potential benefit from descriptors is determined by the ability of the descriptor language to express appropriate constraints. Therefore, we need a powerful language for expressing (and a broad interpretation of what are ) datatype constraints.

Why shouldn't ``an IDREF whose target is an element of type foo'' be a type?

Schema Datatype specification actually defines a standard in which we can write trans-vendor invariants for Data Verification.

This is NOT program verification.




1999-08-20