Question

I have a Mongo document which holds an array of elements.

I’d like to reset the .handled attribute of all objects in the array where .profile = XX.

The document is in the following form:

{
    "_id": ObjectId("4d2d8deff4e6c1d71fc29a07"),
    "user_id": "714638ba-2e08-2168-2b99-00002f3d43c0",
    "events": [{
            "handled": 1,
            "profile": 10,
            "data": "....."
        } {
            "handled": 1,
            "profile": 10,
            "data": "....."
        } {
            "handled": 1,
            "profile": 20,
            "data": "....."
        }
        ...
    ]
}

so, I tried the following:

.update({"events.profile":10},{$set:{"events.$.handled":0}},false,true)

However it updates only the first matched array element in each document. (That’s the defined behaviour for $ – the positional operator.)

How can I update all matched array elements?

Answer 1

UPDATE:
As of Mongo version 3.6, this answer is no longer valid as the mentioned issue was fixed and there are ways to achieve this. Please check other answers.

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At this moment it is not possible to use the positional operator to update all items in an array. See JIRA http://jira.mongodb.org/browse/SERVER-1243

As a work around you can:

• Update each item individually
  (events.0.handled events.1.handled
  …) or…
• Read the document, do the edits
  manually and save it replacing the
  older one (check "Update if
  Current" if you want to ensure
  atomic updates)