mongodb push element into array of objects

Question

I have a collection with a following schema:

{
  "_id" : ObjectId("4ee3ddc346b3b8880a000000"),
  ...
  "msgs" : [{
      "mid" : ObjectId("4ee3ddc346b3b8880a000000"),
      "deleted" : []
    },
    {
      "mid" : ObjectId("4ee3ddc346b3b8880a000100"),
      "deleted" : []
    }]
}

I want to do this query: for the specific _id insert into each "deleted" array an element

so after doing this query I will receive something like this:

{
  "_id" : ObjectId("4ee3ddc346b3b8880a000000"),
  ...
  "msgs" : [{
      "mid" : ObjectId("4ee3ddc346b3b8880a000000"),
      "deleted" : [2]
    },
    {
      "mid" : ObjectId("4ee3ddc346b3b8880a000100"),
      "deleted" : [2]
    }]
}

What I tried to do:

db.dialogs.update(
{ "_id" : ObjectId("4ee3ddc346b3b8880a000000")},
{$addToSet : {'msgs.$.deleted' : 2}}
)

the problem is that it only updating the first element element in the array, instead of all the elements

Any ideas?

Possible duplicate of : stackoverflow.com/questions/4669178/… — DhruvPathak
– DhruvPathak, Commented Dec 11, 2011 at 19:24

James Chen · Accepted Answer · 2011-12-11 16:29:30Z

1

Specify the multiple update option:

db.dialogs.update(
  { "_id" : ObjectId("4ee3ddc346b3b8880a000000")},
  {$addToSet : {'msgs.$.deleted' : 2}},
  false,
  true
)

The last parameter true tells mongodb to update all matching documents. (the third parameter tells mongodb not to do upset).

PS: the above assumes your original query and $ operation is correct, I didn't confirm that in MongoDB.

answered Dec 11, 2011 at 16:29

James Chen

10.9k1 gold badge44 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

DhruvPathak Over a year ago

incorrect. What he wants here is to update several elements of a single document. Not all matching documents.

Collectives™ on Stack Overflow

mongodb push element into array of objects

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related