Projections in MongoDB #205

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ufasoli opened this Issue Jul 30, 2012 · 4 comments

3 participants

@ufasoli

It would be great if the MongoDBQuery could support projections as the HibernateQuery does as explained in this post

According to the Mongo offcial documentation much better performances can be achieved when selecting only relevant fields in a query MongoDB Documentation (Optimization # 3: Select only relevant fields)

Best regards

Ulises Fasoli

@timowest
Querydsl member

Projections can now be used via the overloaded list, singleResult, uniqueResult and listResults methods. The projection type is the same as for the other methods to be consistent with previous Mongodb query behaviour.

e.g. User with only firstName and lastName mapped

User u = query.where(user.firstName.eq("Jaakko")).singleResult(user.firstName, user.lastName);
@timowest
Querydsl member

Released in 3.0.0.BETA1

@timowest timowest closed this Jan 13, 2013
@btiernay

Does this support nested projections? For example, a single field from an array property?

@btiernay

I couldn't find an example that illustrates this use case. Am I overlooking something? Thanks!

@timowest timowest added this to the 3.0.0 milestone Apr 14, 2014
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