Question

我的设置类似于以下设置：

class Project < ActiveRecord:Base
    has_many :targets
    has_many :sectors, :through => :targets, :source => :sector, :conditions => "targets.goal_type = 'Sector'"
    has_many :departments, :through => :targets, :source => :department, :conditions => "targets.goal_type = 'Department'"
end

class Target < ActiveRecord:Base
    belongs_to :project
    belongs_to :goal, :polymorphic => true
    belongs_to :sector, :class_name => 'Sector', :foreign_key => "goal_id"
    belongs_to :department, :class_name => 'Department', :foreign_key => "goal_id"
end

class Sector < ActiveRecord:Base
    has_many :targets, :as => :goal
    has_many :projects, :through => :targets, :conditions => "targets.goal_type = 'Sector'"
end

class Department < ActiveRecord:Base
    has_many :targets, :as => :goal
    has_many :projects, :through => :targets, :conditions => "targets.goal_type = 'Department'"
end

将某个部门分配到项目部门列表时：

p = Project.first
s = Sector.first
p.sectors << s

...导致以下SQL语句（ goal_type IS NULL ）：

INSERT INTO "targets" ("created_at", "updated_at", "goal_type", "project_id", "goal_id") VALUES('2011-11-08 08:53:03.166295', '2011-11-08 08:53:03.166295', NULL, 86, 18) RETURNING "id"

反之亦然（将项目分配到扇区项目列表：

p = Project.first
s = Sector.first
s.projects << p

...正确分配（ goal_type已分配）：

INSERT INTO "targets" ("created_at", "updated_at", "goal_type", "project_id", "goal_id") VALUES('2011-11-08 09:01:46.663663', '2011-11-08 09:01:46.663663', 'Sector', 86, 18) RETURNING "id"

我的问题是：为什么作业在第一种情况下不起作用？

我的设置：Rails 2.3.14，Ruby 1.8.7

Answer 1

你清楚地定义了一个项目的扇区必须具有“goal_type =＆gt;'扇区”（在关联的条件下），而在走另一条路时没有这样的规范。

如果你把条件放在另一边，那么它也会这样。

分配多态关联不适用于两个方向

1 个答案: