Re: Notes on XML Queries proposal

[Rodrigo Moya <rodrigo linuxave net>]

> John Margaglione wrote:
> 
> Hi all,
> 
> I just finished looking at the XML Query proposal.  Looks good, but
> there are a few missing entities (not in the XML entity sense :)
> 
> ORDER BY ( ASC | DESC )
> UNION | INTERSECT
> INNER JOIN, OUTER JOIN and friends.
> Stored Procedures
> 
> Those don't seem to fit into any of the categories so far.  Joins, in
> particular, are funny.  In Oracle you place joins in the WHERE clause:
>     where a.thing = b.thing (+)
> 
> But SQL-92 specifies an
>     INNER JOIN blah on blah
> 
> type of phrasing (I just read the changelog for Postgres 7.0 and it
> uses the SQL-92 INNER JOIN terminology now).  The XML Query spec as
> written doesn't clearly differentiate between a join and a qualifier.
> I imagine a new node alongside of TARGET, SOURCES, VALUES and
> QUALIFICATION.  Perhaps JOINS.
> 
> <!ELEMENT QUERY (TARGET?, SOURCES?, VALUES, QUALIFICATION?)>
> <!ELEMENT JOINS (TABLE, TABLE, FIELD, FIELD)+>
> <!ATTLIST JOIN
>     type CDATA #REQUIRED>
> etc.
> 
> Also, some databases (Interbase comes to mind) allow the user to
> specify the execution plan.  That might be nice too, but far from
> critical.  I'm off to buy a book on XML so I can actually add more
> structured suggestions...
> 
perfect! That was the reason to have it on the web site!

And yes, you're right, something for the joins must be done.