我的模型中包含 "has_many"，但出现 "ActiveRecord::HasManyThroughAssociationNotFoundError" 错误

Question

我正在使用 Rails 5.1。我对如何创建模型和关联感到困惑，其中我有一个连接两个模型的连接 table。下面是我的 PostGres 连接 table 两个 tables ...

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 |

然后我像这样定义模型

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 一个引用

的测试时

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

我收到错误

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

您需要先为联接table本身定义一个has_many，然后您可以定义through关联。否则，Rails 将不知道去哪里寻找弥合差距。

您的连接模型看起来不错。但是您要加入的模型应该如下所示：

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