Mongoid 不在查询中 [英] Mongoid not in query

问题描述

我在使用 mongoid 时遇到了一些问题:

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

测试失败.我尝试使用 where(:id => {'$nid' => [2]})，但效果相同.

Test failed. I've tried to use where(:id => {'$nid' => [2]}), but it have same effect.

怎么了?如何在 mongoid 中使用不在"状态?

What is wrong? How to use "not in" condition with mongoid?

PS，第二个"没问题，第一个"测试通过，因为 id=1

PS, "second" is ok, with "first" test passed, because id=1

推荐答案

试试这个查询:

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

在 MongoDB 中，主键的名称为 _id.Mongoid 试图变得友好，并通过在对象模型中将其别名为 id 来部分地向开发人员隐藏这一事实.但是当你进行查询时，它无法判断你想要主键_id还是一些完全普通的字段id.

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.

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