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Rick Jelliffe on XML Schema

From the TAG list:

XML Schemas is like using a Swiss Army knife to cook with. Most Asian kitchens get by with a handful of simple tools: chopsticks, hatchet, a good knife, perhaps even a spoon. But the logic of  the XSD WG is “Oh, the French need to make quenelles, we must have a quenelling spoon as a grave matter of Internationalization because it is not our business to judge what people need… as long it is more stuff.”    So XSD 1.1 welds another Swiss Army knife onto the existing one, so that no kitchen should suffer without a quenelling spoon.

See also earlier comments on the Schema Experience Workshop from W3C.

So tool-makers blame users for generating non-standard schemas, and users blame the spec for being to difficult to know whether their schemas are standard or not, and spec makers blame tool makers for not implementing the spec properly. Who will free us from this cycle of sin and death?

[...] The only way that XML Schemas can be refactored is with a different core XML Schemas working group. My current expectation is that a lot of nothing will happen until XQuery/XSLT2 becomes seen as a more central technology than XML Schemas; the goal will then be how to support XQuery most minimally.

XSD doesn’t trouble me as much as it troubles Rick, but I have long sympathised with the approach he advocates with Schematron. The RDF equivalent of this is the approach Libby and I called “Schemarama”, expressing constraints against RDF instance data using queries. See original 2001 demo using SquishQL, and a later reworking by Alistair Miles using SPARQL (currently offline?). Recent work from the OWL experts at Clark & Parsia (blog post; another blog post) is heading in the same direction. I wonder whether Rick’s observation about XML applies to RDF too, and that at some point, SPARQL querying facilities will be so ubiquitous in RDF tools that it becomes second nature to apply it to data checking tasks too…?

Update: see also SpinRDF from Holger & co. at Top Quadrant

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