Re: [eclipselink-users] Expression API - Subquery referencing parent que

[Tom Ware <tom.ware@xxxxxxxxxx>]

All EclipseLink queries use the Expression API as the basis - any query that can 
be written in JPA can be written using expressions.

rough pseudo-code:

RAQ query = new ReadAllQuery(Department.class);
EB eb = query.getExpressionBuilder();

RQ rq = new ReportQuery(Employee.class);
rq.addItem(1);
EB innerEb = rq.getExpressionBuilder();
Expression innerExp = innerEb.get("departmentId").equal(eb.get("departementId"));
rq.setSelectionCritiera(innerExp);

Expression outerExp = eb.exists(rq);
query.setSelectionCriteria(outerExp);

-Tom

Tim Hollosy wrote:
> What we're trying to do, is make a utility to do this generically
> within the expression API. We've got a spring service that allows
> developers to create search forms on entities without having to know
> how to work the expression API.
>
> Currently all our code uses expressions to build up the query so it's
> more generic, I'd like to continue to do it this way. Would it be
> possible to mix and match the two if the expression API can't do it?
>
> Tim
>
>
>
> On Tue, Jan 11, 2011 at 2:52 PM, Tom Ware <tom.ware@xxxxxxxxxx> wrote:
> > JPQL like what you have written below should work.  Are you having an issue?
> >
> > Tim Hollosy wrote:
> > > I'm not sure what this is called, but is it possible to create sql
> > > like this with the expression API?
> > >
> > > select * from department d
> > > where
> > > exists (select 1 from employee e where e.department_id = d.department_id)
> > >
> > > This is important when to do when you're paging parent data but want
> > > to search inside child data.
> > >
> > > Thanks!
> > > Tim
> > > _______________________________________________
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