> Are there examples of using XML as a substitute for
> an SQL query? I mean examples of using a DTD to define
> a valid search given as XML as the search criteria in
> a database?
I have seen several approaches to this. None of them seemed all that useful.
> Is it a good idea to make an abstraction of a
> valid database entity in a DTD and make an abstraction of
> a valid search criteria in a DTD? I have searched for such
> examples and I couldn't find any. Maybe the lack of such
> examples is telling me that it is not a way to go. XQL
> is not what we need.
The XML Query Working Group's use cases include "Use Case R" , which performs queries on an XML view of a relational database. The use case assumes these views are created automatically.
 Use Case R (http://www.w3.org/TR/xmlquery-use-cases#rdb)