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我有這些模型:導軌的ActiveRecord的has_many:通過多態關聯
class User < ActiveRecord::Base
has_many :managements, class_name: 'Management', foreign_key: :manager_id
has_many :primary_locations, -> { where managements:
{ manager_role: "primary" } }, through: :managements,
source: :manageable, source_type: 'Location'
has_many :secondary_locations, -> { where managements:
{ manager_role: "secondary" } }, through: :managements,
source: :manageable, source_type: 'Location'
has_many :primary_departments, -> { where managements:
{ manager_role: "primary" } }, through: :managements,
source: :manageable, source_type: 'Department'
has_many :secondary_departments, -> { where managements:
{ manager_role: "secondary" } }, through: :managements,
source: :manageable, source_type: 'Department'
end
用戶可以管理多個部門和位置的,可以是每個伯或仲經理:
class Management < ActiveRecord::Base
belongs_to :manager, class_name: 'User', foreign_key: :manager_id
belongs_to :manageable, polymorphic: true
end
class Location < ActiveRecord::Base
has_many :managements, class_name: "Management", foreign_key: :manageable_id,
as: :manageable
has_many :primary_managers, -> { where management:
{ manager_role: "primary" } }, through: :managements, source: :manager
has_many :secondary_managers, -> { where management:
{manager_role: "secondary"} }, through: :managements, source: :manager
end
class Department < ActiveRecord::Base
has_many :managements, class_name: "Management", foreign_key: :manageable_id,
as: :manageable
has_many :primary_managers, -> { where management:
{ manager_role: "primary" } }, through: :managements, source: :manager
has_many :secondary_managers, -> { where management:
{manager_role: "secondary"} }, through: :managements, source: :manager
end
的以下協會產生錯誤時,我致電user.primary_departments
:
SELECT "departments".* FROM "departments" INNER JOIN "managements" ON
"departments"."id" = "managements"."manageable_id" WHERE
"managements"."manager_role" = 'primary' AND "managements"."manager_id" = $1
AND "departments"."manageable_type" = 'Department' [["manager_id", 1]]
PG::UndefinedColumn: ERROR: column department.manageable_type does not exist
location.primary_managers
協會工作。所以它似乎幾乎工作,除了多態類型指向錯誤的表格。如何在management
表中找到manageable_type
?
您有一個錯字問題:在where方法中總是使用複數名稱:'where(managements:{manager_role:'primary'})'(注意管理上的複數) – MrYoshiji
謝謝。其實我有不同的表格名稱,爲了簡化問題我已經審查過。我將編輯以反映問題中的表名。 –
我有完全相同的問題。肯定會喜歡解決方案。但是當我從頭開始構造一個多態結構時,一切都有效。 –