Re: Notes on XML Queries proposal

[Vivien Malerba <malerba linuxave net>]

On jeu, 11 mai 2000, you 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...
> 
> John
> 

Ok, I'll wait for your proposals and I will start implement a XMLQuery object
as soon as I have a little time for it.

Regards,

Vivien