$elemMatch in field.include

[toppac]

Does Spring Data support the elemMatch projections?

http://docs.mongodb.org/manual/reference/projection/elemMatch/


Using the query.fields.include() it does not appear to work, since this method treats every field as a <field>:1 in the underlying mongo query. What I really want is a

{ _id: 0, dependents: { $elemMatch: { school: 102 }}};

Can anyone let me know if this is possible with Spring Data or even the Java Driver?

[anztenney]

We're trying to do the same thing. I've found a forum saying using the @Query annotation someone got it working, but is there a way to do this through the Query classes?

[kl3os]

Hi,

Did you finally find a way to do it with Spring Data?

Cheers
Kim

[mevric75]

I had similar requirement. Following worked for me. Finding this was a nightmare.

Query q1 = new Query(Criteria.where("topElementId").is("B00121")) ;
Query q2 = new Query(Criteria.where("innerArrayElement").elemMatc h(Criteria.where("_id").is(new ObjectId(someId))));
BasicQuery bsq = new BasicQuery(q1.getQueryObject() , q2.getQueryObject());
template.findOne(bsq, TopClassName.class);

The _id can be replaced with any element from the innerArrayElement.



------------------------
Following is the mongo and spring data sample.

db.schools.find( { zipcode: 63109 },
{ students: { $elemMatch: { school: 102 } } } )


Query q1 = new Query(Criteria.where("zipcode").is("63109"));
Query q2 = new Query(Criteria.where("students").elemMatch(Criteri a.where("school").is("102")));
BasicQuery bsq = new BasicQuery(q1.getQueryObject() , q2.getQueryObject());
template.findOne(bsq, SchoolList.class);

[anztenney]

The answer given by mevric75 is exactly what we ended up doing as well.