[xquery-talk] Order of results in XQuery expressions
Enric Jaen
enricjaen at yahoo.es
Tue Dec 5 03:01:27 PST 2006
I am testing with Berkeley DBXML. I have to say that
in general the results follow a document order, but I
have noticed with some mixed-content documents a
non-deterministic order. But I have not been able to
determine a pattern when this occurs. Maybe is simply
an implementation bug.
For example, if I have a mixed document:
<foo>
1 <1> 1 </1> 1
2 <2> 2 </1> 2
3 <3> 3 </3> 3
4 <4> 4 </4> 4
</foo>
and I do " foo/* " then I get this unexpected order:
<2>2</2>
<3>3</3>
<1>1</1>
<4>4</4>
even when I put ordered{ }
But thanks, at least now I know that I should expect
a document order.
I have tried also with Saxon and I think it orders
well.
/Enric
--- Michael Kay <mike at saxonica.com> escribió:
> > <nitpick>
> > Though this is the way how all XQuery processors
> that I am
> > aware of behave, it is not actually demanded by
> the specs.
> > Rather, the default setting of `ordering mode' (if
> nothing is
> > set in the query prolog) is implementation-defined
> (Sect.
> > 4.7, XQuery 1.0 CR).
> > </nitpick>
>
> Technically you are right (and I deliberately
> glossed over this point,
> because I thought it was unlikely to help the OP
> with his problem). The
> results of unordered evaluation of path expressions
> can be so weird that I
> don't think any processor would make this the
> default. For
> "implementation-defined" read "may be controlled
> using an
> implementation-defined API".
>
> Michael Kay
>
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