Re: SQL/XML extension

Paul, Rob,

I just read with some interest your paper on XML queries with PostgreSQL.   
I'm particularly puzzled by some of your conclusions, and thought you might 
want to discuss them with the PGSQL-Hackers mailing list.

Particulary:
Functions should be able to have a variable amount of arguments.

I find this conclusion odd, because function overloading (that is, the idea 
that a function is defined by the combination of its name and the number and 
type of arguments) is now enshrined in the SQL2003 standard.      Of course, 
I wouldn't be at all surprised to find out that the SQL committee had broken 
their own standard.  ;-)

Re-defining AS would, as you notice, break many things.   However, you could 
easily get around this through quoting.  While that would not be exactly 
adherent to the standard, it's easier that re-writing the parser.

In some ways, it seems to me that SQL/XML might be better defined as a 
separate interface to the database; that is, it's own "shell" which is 
incompatible with SQL (since the committee seems to have deliberately made it 
incompatible).  

Thoughts?

-- 
Josh Berkus
Aglio Database Solutions
San Francisco