Sorry forgot to add using Cay3-RC1 (congrats on the release!)
2010/1/12 Steve Wells <[email protected]>
> 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
>
