addToSet using java api

[Omprakash Verma]

Dear All,

                We are now using mongodb for our internal project to get experience on it. Here is one issue, in which I need your help..

I have a table ..

book_issued

Fields : user_id, book_id

Table data are like 

user_id  book_id

1           1

1           4

2           5

2           6

I want to show it as grouped using java api.

user_id  book_id

1           1,4

2           5,6

Please suggest and help me. We are using $match and $group.

Thanks,

Op

[Rob Moore]

I just pushed an example application using the asynchronous Java driver up to GitHub.

The pipeline it generated is:

'$pipeline' : [

  {

    '$match' : {

      'user_id' : {

        '$gt' : 0,

        '$lt' : 10

      },

      'book_id' : {

        '$gt' : 0,

        '$lt' : 10

      }

    }

  }, 

  {

    '$group' : {

      '_id' : '$user_id',

      'book_id' : { '$addToSet' : '$book_id' }

    }

  }

]

And gives the results:

{

  '_id' : 2,

  'book_id' : [

    6, 

    5

  ]

}

{

  '_id' : 1,

  'book_id' : [

    4, 

    1

  ]

}