Re: [PATCH] Add XMLEXISTS function from the SQL/XML standard

On ons, 2010-05-26 at 11:47 +0100, Mike Fowler wrote:
> > The XMLEXISTS function works with XQuery expressions and doesn't have
> > the call signature that your patch implements
>
> Looking at the manuals of Oracle, Derby and DB2 I see how the call
> signature differs. I also note that Oracle's implementation is XPath
> only, Derby's is partial XQuery and DB2 appears to be full XQuery.
>
> What do people prefer me to do? I see the options as:
>
> 1) Change the call signature to match the standard
> 2) Change the function name back to xpath_exists

It would be nice to make XMLEXISTS work as in the standard, seeing how
many others are providing the same interface.

> Should option one be the more popular there's further choices:
>
> 1) Integrate XQuery support to completely match the standard, however
> this will require the addition of a new library libxquery
> 2) Leave the XPath as is, inline with Oracle's implementation
> 3) Hybrid approach. Since XML is a comple time option, add XQuery as
> another. Conditional completion gives the full XQuery support when
> available or just the XPath when not

I think providing XPath is enough, at least for now.