[hibernate-dev] [OGM] @JoinColumns, @EmbeddedId & IN_ENTITY mode

[Emmanuel Bernard]

Hey Guillaume,
I think I have properly fixed the issue. Can you test and review the
pull request https://github.com/hibernate/hibernate-ogm/pull/141 ?
Sanne it would be useful for you to check it out too.

Emmanuel

On Tue 2012-09-25  9:58, Emmanuel Bernard wrote:
> Let me investigate this further first. Ideally the engine would use the right column names ie the fk and not the ones from the entity ids. 
> I must have messed up when I fixed the bug I discussed with you. 
> 
> On 24 sept. 2012, at 20:20, Guillaume SCHEIBEL <guillaume.scheibel at gmail.com> wrote:
> 
> > Hi guys,
> > 
> > I'm working on OGM-236 which consists to use by default the IN_ENTITY mode
> > for association storage strategy instead of COLLECTION.
> > I've just found out a little issue, when we use @JoinColumns over a
> > @OneToMany property to map an @EmbeddedID with the IN_ENTITY mode, the
> > navigation information are not stored directly into the document itself but
> > another document composed by the join columns as the _id and the navigation
> > information (in that case the IDs that the entity is related to).
> > 
> > Concretely, let's starting from this mapping:
> > https://github.com/hibernate/hibernate-ogm/blob/master/hibernate-ogm-core/src/test/java/org/hibernate/ogm/test/id/Label.java
> > https://github.com/hibernate/hibernate-ogm/blob/master/hibernate-ogm-core/src/test/java/org/hibernate/ogm/test/id/News.java
> > https://github.com/hibernate/hibernate-ogm/blob/master/hibernate-ogm-core/src/test/java/org/hibernate/ogm/test/id/NewsID.java
> > 
> > and run this test with the IN_ENTITY mode on (to make the switch, a
> > modification into MongoDBDatastoreProvider.configure() is needed)
> > https://github.com/hibernate/hibernate-ogm/blob/master/hibernate-ogm-core/src/test/java/org/hibernate/ogm/test/id/CompositeIdTest.java
> > 
> > 
> > We can expect to have something like:
> > 
> > {
> >    "_id": {
> >        "author": "Guillaume",
> >        "title": "There are more than 20 JUGs in France"
> >    },
> >   "content": "Great! Congratulations folks",
> >    "labels": [
> > 
> >        { "id": NumberLong(5) }
> > 
> > ]
> > 
> > }
> > 
> > It means this News is related to 1 Label of which ID is 5.
> > But due to @JoinColumns we got this (both documents are from the News
> > collection):
> > 
> > {
> >    "_id": {
> >        "author": "Guillaume",
> >        "title": "There are more than 20 JUGs in France"
> >    },
> >    "content": "Great! Congratulations folks",
> >    "labels": []
> > } {
> >    "_id": {
> >        "news_author_fk": "Guillaume",
> >        "news_topic_fk": "There are more than 20 JUGs in France"
> >    },
> >    "labels": [{
> >        "id": NumberLong(5)
> >    }]
> > }
> > 
> > Of course at the loading, when the News seems not related to any Label
> > because the "labels" field is empty.
> > A workaround it to change the @JoinColumns from:
> > 
> > @JoinColumns({@JoinColumn(name="news_topic_fk", referencedColumnName =
> > "newsid.title", nullable = false) ,
> >          @JoinColumn(name="news_author_fk", referencedColumnName =
> > "newsid.author", nullable = false)})
> > private List<Label> labels;
> > 
> > @JoinColumns({@JoinColumn(name="title", referencedColumnName =
> > "newsid.title", nullable = false) ,
> >          @JoinColumn(name="author", referencedColumnName =
> > "newsid.author", nullable = false)})
> > private List<Label> labels;
> > 
> > Note that the new value of each @JoinColumn's name is the same as
> > referenced property from the @Embedded entity.
> > 
> > I see there are 2 fix possible for this issue:
> > - we can say in case of IN_ENTITY mode don't use @JoinColumns' name to
> > store the navigation property but the property from the referenced
> > column.
> > - at the loading, we can check also the documents created due to @JoinColumns
> > 
> > Personally, I would tend to the first approach which is more natural
> > in terms of storage and more readable.
> > 
> > What do you think ?
> > Let me know if you need more information.
> > 
> > Guillaume
> > _______________________________________________
> > hibernate-dev mailing list
> > hibernate-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/hibernate-dev
> 
> _______________________________________________
> hibernate-dev mailing list
> hibernate-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/hibernate-dev