I'm not sure what will happen when you pass this:
(Key) null
As the query parameter. Instead, what happens if you query on "parentKey ==
null"?
On Tue, Dec 29, 2009 at 11:47 AM, dantuluri <pdantul...@gmail.com> wrote:
> Hi,
>
> I have the following code:
>
> query = pm.newQuery(File.class);
> query.setFilter("parentKey == parentKeyParam");
> List<File> storedFiles = (List<File>)query.execute((Key)null);
>
> This query is returning all the Files including those with
> parentKey not null.
>
> What is wrong with this query? I am kinda stuck. Please help me.
>
> Thanks
>
> On Dec 28, 1:24 pm, "Ikai L (Google)" <ika...@google.com> wrote:
> > You should be able to query for a null value, but you will not be able to
> > query for an empty value. What is the query you are issuing? What is this
> > returning?
> >
> >
> >
> >
> >
> > On Wed, Dec 23, 2009 at 8:29 AM, dantuluri <pdantul...@gmail.com> wrote:
> > > I am new GAE and I need some help. Is it possible to query for
> > > entities with a property value null using GAE JDO query?
> >
> > > I want something like
> >
> > > "Get me all the Files that don't have a parent"
> >
> > > In regular relational DBs, it can be queried some thing like this:
> > > "select * from File where parentKey is null"
> >
> > > I have a class something like this:
> >
> > > public class File {
> > > @Persistent
> > > @PrimaryKey
> > > private Key id;
> >
> > > @Persistent
> > > String name;
> >
> > > @Persistent
> > > private Key parentKey;
> > > }
> >
> > > When I am querying for Files that have null parentKey, query returns
> > > all Files including those with non-null parentKey value. Is this
> > > possible to do with GAE?
> >
> > > Thanks!
> >
> > > On Dec 22, 1:33 pm, dantuluri <pdantul...@gmail.com> wrote:
> > > > Hi,
> >
> > > > I have an entity that has the following structure:
> >
> > > > File which has Key as primary key and ParentKey that refers to
> > > > another File which is parent of this File. Example data for this
> > > > structure looks like this:
> >
> > > > Key: File(2)
> > > > Name: Inbox
> > > > parentKey: File(1)
> >
> > > > It is possible that File may not have a parentKey.
> >
> > > > I want to query the DataStore for Files that don't have parent file
> > > > (parentKey == null). But when I am querying with parentKey == null, I
> > > > am still getting all Files including those with parentsKeys. How can
> > > > we do this with JDO query with App Store? I must be missing something
> > > > basic here.
> >
> > > > Similarly I would like to get the child folders of a given folder
> > > > (parentKey == File(1)).
> >
> > > > Any help would be appreciated!
> >
> > > > Thanks
> >
> > > --
> >
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> > --
> > Ikai Lan
> > Developer Programs Engineer, Google App Engine
>
> --
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>
--
Ikai Lan
Developer Programs Engineer, Google App Engine
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