update array of embedded documents with array of embedded documents

[Martinus Martinus]

Hi,

Is there any mongodb command to do updating an array of embedded documents with array of embedded documents? So supposed I have below existing document :

{

    "_id" : 1,

    "name" : "Bob",

    "year" : 2012,

    "animal_ref" : DBRef("animal", ObjectId("1")),

    "array" : [{

                    "date" : ISODate("2012-11-11T09:00:00Z"),

                    "food" : 10

                  },

                  {

                    "date" : ISODate("2012-11-11T18:00:00Z"),

                    "food" : 10

                  }]

}

And I have a new "array" to be combined with the existing array like below :

    "array" : [{

                    "date" : ISODate("2012-11-11T09:00:00Z"),

                    "food" : 15

                  },

                  {

                    "date" : ISODate("2012-11-11T19:00:00Z"),

                    "food" : 20

                  }]

And the result of this combining process will become like below :

{

    "_id" : 1,

    "name" : "Bob",

    "year" : 2012,

    "animal_ref" : DBRef("animal", ObjectId("1")),

    "array" : [{

                    "date" : ISODate("2012-11-11T09:00:00Z"),

                    "food" : 15

                  },

                  {

                    "date" : ISODate("2012-11-11T18:00:00Z"),

                    "food" : 10

                  },

                  {

                    "date" : ISODate("2012-11-11T19:00:00Z"),

                    "food" : 20

                  }]

}

Thanks.

               

[Asya Kamsky]

Martinus,

There is a way to do this, it's described in the manual here:  http://docs.mongodb.org/manual/reference/operators/#_S_each

What you want to use is an update with "$addToSet" operator and "$each" operator to specify the new array and have only non-duplicates added to existing array.

For you that would be:  db.collection.update(  { <query>} ,  { $addToSet : { array : { $each : [ <new array you want to merge ] } } } )

Asya

[Martinus Martinus]

Hi Asya,

Thanks for your answer. It's worked.

Thanks again and Happy New Year 2013.

Best regards,

Martinus

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