Rails多个belongs_to关联

Question

我有附图中的模式

现在在答案模块中我有以下代码

class Answer < ActiveRecord::Base
    belongs_to :project, class_name: "Project", foreign_key: "project_id"
    belongs_to :questionair, class_name: "Questionair", foreign_key: "questionair_id"
end

这些belongs_to行是否正确？当我删除项目时，答案会按预期被删除，但在问卷调查的情况下，它无法删除相关的答案行。 我必须做些什么。我有：

class Project < ActiveRecord::Base
    has_many :answers, dependent: :destroy
end
class Questionair < ActiveRecord::Base
    has_many :answers, dependent: :destroy
end 

Answer 1

试试这种方式

class Answer < ActiveRecord::Base
    belongs_to :project
    belongs_to :questionair
end

class Project < ActiveRecord::Base
    has_many :answers, dependent: :destroy
end

class Questionair < ActiveRecord::Base
    has_many :answers, dependent: :destroy
end 

要删除关联记录，您必须使用

project.destroy

如果您使用

project.delete #this does not trigger dependent destroy

Answer 2

我如何理解你，你只想在单个命令中销毁所有依赖项：

project.destroy 
# delete all nested answers, 
# questionairies and questionairies->answers

因此，您需要在项目模型中添加一行。

class Project < ActiveRecord::Base
  has_many :answers, dependent: :destroy
  has_many :questionairies, dependent: :destroy
end

而不是

class Project < ActiveRecord::Base
    has_many :answers, dependent: :destroy
end

如果我理解你的错误，请更深入地解释你的问题。