在我的模型中包含了"has_many“，但是我会遇到一个has_many错误

Question

我正在使用Rails 5.1。我很困惑如何创建一个模型和关联，其中我有一个连接两个模型的联接表。下面是两个表的PostGres连接表.

mydb=# \d organization_workers;
                               Table "public.organization_workers"
      Column       |  Type   |                          Modifiers
-------------------+---------+--------------------------------------------------------------
 id                | integer | not null default nextval('organization_workers_id_seq'::regclass)
 organization_id        | integer |
 stratum_worker_id | integer |

所以我定义了这样的模型

class Organization < ApplicationRecord

  has_many :stratum_workers, :through => :organization_workers



class OrganizationWorker < ApplicationRecord
  belongs_to :organization
  belongs_to :stratum_worker
end

但是当我运行一个测试时

assert_false organization.stratum_workers.empty?, "A pre-condition of this test is thta the org have stratum workers."

我知道错误了

Error:
OrganizationTest#test_Test_total_paid:
ActiveRecord::HasManyThroughAssociationNotFoundError: Could not find the association :organization_workers in model Organization
    test/models/organization_test.rb:7:in `block in <class:organizationTest>'

Answer 1

首先需要为联接表本身定义一个has_many，然后才能定义through关联。否则，Rails将不知道在哪里寻找桥梁。

你的加入模型看上去不错。但是你加入的模特应该是这样的：

class Organization < ApplicationRecord

  has_many :organization_workers
  has_many :stratum_workers, through: :organization_workers

end


class StratumWorker < ApplicationRecord

  has_many :organization_workers
  has_many :organizations, through: organization_workers

end