Question

I’m using MongoDB and Spring 3. I have the following domain object:

@Document(collection = "users")
public class User {

    @Id
    private String id;

    private List<Post> posts;
}

I want to add a Post to a User, but what is the best/most efficient way to do that? I can see a way to do this programmatically – find the user, add a new post object to the list and save the user again – but I don’t think this is very elegant or efficient.

From the documentation it seems like I need to use the $push operator but I can’t seem to find any examples of how to do this with Spring’s MongoTemplate. Can anyone provide an example?

Answer 1

$push would be the correct way to add a new document to the array.

You can see example code in this presentation (slide 22). The relevant line would be:

mongoTemplate.updateFirst(collection, 
... new Query(where("_id").is(...)),
... new Update().push("field", dbo));