CODEWITHSUNDEEP
google-app-enginejdo
tobik
tobik

Reputation: 7198

AppEngine and JDO: fetch objects in unowned relationship

Unowned one-to-many and many-to-many relationships are defined using Sets or Lists of Keys. Let's say I have an object of an article containing set of keys of labels of the article. So how do I fetch the labels themselves? The objects matching the keys? How do I iterate over them? Naturally I could iterate over the keys and fetch the objects separately, but is this the only way? I tried to find the answer everywhere but I wasn't successful. The documentation describes defining unowned relationships in detail, but is silent about making queries on them...

Upvotes: 0

Views: 499

Answers (1)

DataNucleus
DataNucleus

Reputation: 15577

You mean you have what Google was originally calling an "unowned relation" ? (where you have a Set<Key>). Sadly that is not a relation at all IMHO, since there is no related object involved. With v2.x of their plugin you can have a real unowned relation (the example there is for 1-1, but you can equally have Set<B>) where everything looks as it should. I'd strongly advise you to use that (the keys are stored in the parent, so a single call is made to get the Set of related objects).

Upvotes: 1

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