MongoDB dot notation query

Question

I have a BasicDBObject which while debugging seems to hold:

{ "_id" : { "p_key" : { "$date" : "2012-02-02T00:00:00Z"} , "d_key" : 222} , "t_key" : 10195 , "w_key" : 4 , "f_key" : { "$date" : "2012-02-02T00:00:00Z"}}

Now, when I try:

dbObject.get("_id.d_key"));

I get a null pointer exception.

Any thoughts on what I am doing wrong here?

I am trying to get the value of d_key inside _id.

Answer 1

DBObject and it's children do not support dot notation gets. You will have to do :

if(dbObject.containsField("_id"))
    ((DBOBject)dbObject.get("_id")).get("p_key")

That's an extremely large _id field by the way. It will result in huge indexes which is generally not a good idea.