CODEWITHSUNDEEP
mongodbmongodb-querymongo-java
Karthik Balasubramanian
Karthik Balasubramanian

Reputation: 1157

Match Query - MongoDB

Am using mongo to store my documents. And one of them looks like below.

Name:
  first: joe
  last: blo
address:
  city: Paris
  state: London
relatives:
  first order:
      aunt: ashley
      uncle: tom
  second order
      aunt: roma
      uncle: robin

I would like to be able to perform a query which would give me documents that match 'aunt':'roma'. Am using mongo java api to access it

From what I have understood and read the following query should work, but it doesnt

 DBObject winner = new BasicDBObject("$match", new BasicDBObject("aunt", "roma") );
 System.out.println("count "+coll.aggregate(winner).getCommandResult());

Can anyone help me understand and explain why this is failing?

Thanks K

Upvotes: 0

Views: 432

Answers (1)

rdonatoiop
rdonatoiop

Reputation: 1185

My suggestion is that, for better understanding, you practice a bit using the MongoDb javascript console to test your queries first against your database collections, then later you get to write them directly for the driver you are using (Java in your case). An example:

To match a document described like this 

{
    name: {
        first: "joe",
        last: "blo"
    } ,
    address: {
        city: "Paris",
        state: "London"
    },
    relatives: {
        first_order: {
            aunt: "ashley",
            uncle: "tom"
        },
        second_order: {
            aunt: "roma",
            uncle: "robin"
        }
    }
}

you would build a query like this

db.my_collection.find({"relatives.second_order.aunt": "roma"})

To have the document inserted into a collection called my_collection, it´s simple as

db.my_collection.insert(
{
    name: {
        first: "joe",
        last: "blo"
    } ,
    address: {
        city: "Paris",
        state: "London"
    },
    relatives: {
        first_order: {
            aunt: "ashley",
            uncle: "tom"
        },
        second_order: {
            aunt: "roma",
            uncle: "robin"
        }
    }
})

Some references you may read to get your queries properly written to Java API: http://docs.mongodb.org/ecosystem/tutorial/getting-started-with-java-driver/

And the docs for playing around with the MongoDb console, in this case with querying subdocuments: http://docs.mongodb.org/manual/reference/method/db.collection.find/#query-subdocuments

Hope it helps.

Upvotes: 1

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