How to find records by foreign key (dbref) in morphia and mongodb?

Question

I have following entity:

class Linf {
     @Id
     ObjectId id;
     @Reference
     Denied denied;
}

I want to find all Linfs that have Denied object with certain id. How can I do this? Will this query employ indexes? I want to avoid full scan if possible.

Thanx.

score 1 · Answer 1 · answered Dec 18 '13 at 19:00

1

If you don't have an index on "denied" it'll be a full collection scan either way but something like this should do it for you:

datastore.createQuery(Linf.class).field("denied").equal(new Key<Denied>(Denied.class, id)).fetch()

answered Dec 18 '13 at 19:00

evanchooly

6,102
1
16
23

1

I get WARNING: The type(s) for the query/update may be inconsistent; using an instance of type 'com.github.jmkgreen.morphia.Key' for the field 'org.kriyak.orm.Linf.denied' which is declared as 'org.kriyak.orm.Denied' – Stepan Yakovenko Dec 20 '13 at 15:56
That's fixed, I believe, in the official version. James's fork has been essentially shut down in favor of the official version. Please update to the other version and see if that persists. It's just a warning in any case but I believe I fixed that. If it's not in 0.105 it'll be in 0.106 which I'll release after the new year. – evanchooly Dec 20 '13 at 19:45

score 1 · Accepted Answer · answered Dec 21 '13 at 14:50

1

This works for me:

    Denied d2 = new Denied();
    d2.id = new ObjectId("52b4709f423d856472c34fa1");

    List list = datastore
            .createQuery(Linf.class)
            .field("denied")
            .equal(d2).asList();

answered Dec 21 '13 at 14:50

Stepan Yakovenko

8,670
28
113
206

How to find records by foreign key (dbref) in morphia and mongodb?

2 Answers2