Mongoid not in query

Question

I have some trouble with mongoid: ``` test "Test candidate" do User.create(:id => 1, :sex => User::Male, :country => 1, :city => 1) User.create(:id => 2, :sex => User::Female, :country => 1, :city => 1) User.create(:id => 3, :sex => User::Female, :country => 1, :city => 1) user = User.not_in(:id => [2]).second assert_not_equal(user.id, 2) end ``` Test failed. I've tried to use where(:id => {'$nid' => [2]}), but it have same effect. What is wrong? How to use "not in" condition with mongoid? PS, "second" is ok, with "first" test passed, because id=1

Accepted Answer

Try this query:

```
user = User.not_in(:_id => [2]).second
```

In MongoDB primary key has name `_id`. Mongoid tries to be friendly and partially hides this fact from the developer by aliasing it to `id` in the object model. But when you do queries, it cannot tell if you want primary key `_id` or some completely ordinary field `id`.

Mongoid not in query

Solution

Problem