[xquery-talk] RE: Future of XQuery and XQuery Update Faclilty
jonathan.robie at redhat.com
Mon Oct 22 10:07:21 PDT 2007
Thomas Lord wrote:
> Why is there a need for XQUF?
Because people need to make changes to data.
> Pending updates could be expressed in straight XML. Why
> is a new and non-externalizable type needed to supplement
The pending update list is purely an abstraction used internally by an
implementation. What benefit would there be to externalizing it in a
standard way? How would you propose to do this with "straight XML"?
> It seems a horrible rule, not least because of the
> segregation of "declare updating function" procedures from
> "declare function" in the static type rules for XQuery.
A great deal of optimization in XQuery is based on the assumption that
there are no side effects. Updates invalidate that assumption. Also, the
user generally knows that calling a function does not result in changes
to the underlying data. For both the compiler and the user, I think it's
helpful to identify functions that update.
More information about the talk