| erik@jpox.org 2006-02-10, 7:45 am |
| Thanks for the comments, I agree with you all.
Regards,
Quoting Michael Bouschen <mbo.tech@spree.de>:
> Hi,
>
> I have the same understanding of the semantics of projections of
> collection and map fields as Wes and Bin Sun. The query would return the
> collections or maps as single cells, so the query result would be a list
> of collections or maps. I also agree that support for projections of
> collection and map fields does not add much value, but AFAIK the current
> spec allows this.
>
> I think the shape of the query result is different whether projecting a
> collection field or including a variable in the result that iterates the
> collection:
> (1) SELECT employees FROM Department
> (2) SELECT e FROM Department WHERE employees.contains(e)
> The first query returns a list of collections of employees, so for each
> department it returns the department's employee collection. Query (2)
> returns a list of employees, where each returned employee is included in
> an employee collection of at least one department.
>
> Given the above is correct, JDOQL would never return Map.Entry
> instances. Either the query projects the entire map or it iterates the
> map using containsKey or containsValue, but there is no contains for maps.
>
> Regards Michael
>
>
>
> --
> Michael Bouschen Tech@Spree Engineering GmbH
> mailto:mbo.tech@spree.de http://www.tech.spree.de/
> Tel.:++49/30/235 520-33 Buelowstr. 66
> Fax.:++49/30/2175 2012 D-10783 Berlin
>
|