On 8/17/06, Mike Kienenberger <mkienen..mail.com> wrote:
> On 8/17/06, Andrus Adamchik <andru..bjectstyle.org> wrote:
> > > simply have a query.setJoinType(JoinType.OUTER) to enable and disable
> >
> > I would say this should be done in Expression, not Query, as this
> > affects individual joins.
>
> Technically, I think it's going to be challenging to implement this at
> the Expression level rather than the query level. By the time the
> SelectTranslator gets involved, it looks to me like the joins have all
> already been disassociated with the Expressions. It's unclear to me
> whether all of the qualifiers have been disassociated with the
> expressions at this point, but I think this wouldn't be a problem.
>
> At least in Oracle, I need to add a (+) after every outer-joined-table
> column name in the join qualifiers ["db relationship joins"] and after
> every outer-joined-table column name in the selection qualifiers
> ["parent qualifier"].
>
> I think in my own use cases, like Øyvind's, I'm ok with everything
> being an outer join if anything is an outer join.
Oops. I wasn't quite ready to hit send yet -- I was still working
through all of this :-)
It's now looking like QueryAssemblerHelper can also record whether
something is an outer join when creating the join list at the same
time it's outputting the column names.
So, perhaps I spoke too soon.
One thing that is going to be annoying is having to specify an outer
join for every expression. I'm thinking we could have an "effective
outer join" value which, if not specified on the current Expression,
inherits from the parent expression. So an Expression join type by
default would be "unspecified" which means ask the parent. Any root
expression with unspecified would default to an inner join.
This archive was generated by hypermail 2.0.0 : Thu Aug 17 2006 - 15:35:33 EDT