Question

I’ve got an array of referenced objects in a Mongoid document. Using current_user.add_to_set(:whatever, @object.id) works just fine, adding an BSON ObjectId element to the array and saving current_user.

However, when I try to remove the element with pull_all, it’s doesn’t work. Nothing seems to happen:

current_user.pull_all(:whatever, BSON::ObjectId(@object.id))

Any idea what I’m doing wrong?

Thanks!

Answer 1

You need to wrap the items you want to pull_all in an array, I ran something (in Mongoid 2.0.2) similar to this and it worked fine:

current_user.add_to_set(:whatever, @object.id) # worked exactly as you said, added the id to the `whatever` array
current_user.pull_all(:whatever, [@object.id]) # removed the id from the `whatever` array

That way, you can also specify multiple ids to remove, in one operation, thusly:

current_user.pull_all(:whatever, [@object1.id, @object2.id])