This short article makes a number of good points about design of XML Schemas and they also apply to DFDL schemas.

http://www.xfront.com/HideVersusExpose.pdf

I would summarize it as "define types, not elements", though there is a little bit more to it than that.

Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com
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