Quoting Robert Haas <robertmh...@gmail.com>:


I'm not sure I understand how this more convenient than just using
xpath() with exists()?


It will save a lot of complexity in WHERE clauses. For example using exists() in xpath() you might construct something like:

WHERE array_dims(xpath('exists(/foo/bar)','<bar><foo/></bar>'::xml) IS NOT NULL ...

Whereas a dedicated xpath_exists() would look like:

WHERE xpath_exists('/foo/bar','<bar><foo/></bar>'::xml) ....

I accept this example is quite basic, but I hope it illustrates the added usability. I think xml in sql is complex enough, especially when you start considering namespaces, that anything we can do to simplify common use cases can only help improve the uptake of postgres xml.

Thanks,

--
Mike Fowler


--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

Reply via email to