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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
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