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From Andrey Razumovsky <razumovsky.and...@gmail.com>
Subject Re: EJBQL with aggregrate function render to Java List
Date Tue, 12 Jan 2010 08:53:54 GMT
Nope, unfortunately (correct me if i'm wrong) Cayenne doesn't support
constructors in EJBQL (yet)

2010/1/12 Steve Wells <websystemz@gmail.com>

> Sorry forgot to add using Cay3-RC1 (congrats on the release!)
>
> 2010/1/12 Steve Wells <websystemz@gmail.com>
>
> > Hi All,
> >
> > I have an EJBQL query selecting a grouped value from a master table
> > (Category.name) and the count of detail rows for each grouping (ie count
> of
> > the Category.questions), so I get results:
> > cat1, 5
> > cat2, 3
> > cat3, 10
> > etc...
> >
> > Ideally what I need to do is get the results into a java List<?>, so I
> was
> > hoping (by waving magic Cayenne wand!) that this would work:
> >
> > "select new CategorySummary(c.name, count(q)) from Category c left join
> > c.questions q group by c.name" returning a List<CategorySummary>...but I
> > can't get it working.  Is there a prescribed approach for this?
> >
> > At the moment I get this:
> >
> > java.lang.NullPointerException
> >       at
> org.apache.cayenne.ejbql.parser.Compiler.compileEntityResult(Compiler.java:219)
> >       at
> org.apache.cayenne.ejbql.parser.Compiler.compile(Compiler.java:200)
> >       at
> org.apache.cayenne.ejbql.parser.EJBQL$EJBQLDefaultParser.compile(EJBQL.java:30)
> >       at
> org.apache.cayenne.query.EJBQLQuery.getExpression(EJBQLQuery.java:122)
> >       at
> org.apache.cayenne.query.EJBQLQueryMetadata.resolve(EJBQLQueryMetadata.java:38)
> >       at
> org.apache.cayenne.query.EJBQLQuery.getMetaData(EJBQLQuery.java:66)
> >       at
> org.apache.cayenne.util.ObjectContextQueryAction.<init>(ObjectContextQueryAction.java:79)
> >       at
> org.apache.cayenne.access.DataContextQueryAction.<init>(DataContextQueryAction.java:48)
> >       at
> org.apache.cayenne.access.DataContext.onQuery(DataContext.java:1278)
> >       at
> org.apache.cayenne.access.DataContext.performQuery(DataContext.java:1267)
> >       at
> org.apache.click.extras.cayenne.CayenneTemplate.performQuery(CayenneTemplate.java:276)
> >
> >
> >
> > CategorySummary.java:
> >
> > CategorySummary {
> >     private String name;
> >     private Number count;
> >
> > plus getters and setters
> >
> > The EJB spec says you can do something like:
> >
> > SELECT NEW com.acme.example.CustomerDetails(c.id, c.status, o.count)
> > FROM Customer c JOIN c.orders o
> > WHERE o.count > 100
> >
> > Does Cayenne support this?
> >
> > Thanks for any help,
> >
> > Steve
> >
>



-- 
Andrey

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