has_many通过关联可以是多态吗？

Question

我有一个has_many飞行员的船模型。飞行员可以是角色或派系。我可以使用has_many：通过关联来对此进行建模吗？

class Ship < ActiveRecord::Base 
    has_many :pilots, :through => :pilot_assignments, :polymorphic => true 
    has_many :pilot_assignments 
end 

class Character < ActiveRecord::Base 
    has_many :ships, :through => :pilot_assignments 
    has_many :pilot_assignments 
end 

class Faction < ActiveRecord::Base 
    has_many :ships, :through => :pilot_assignments 
    has_many :pilot_assignments 
end 

class PilotAssignment < ActiveRecord::Base 
    belongs_to :ship 
    belongs_to :pilot, :polymorphic => true 
end 

Answer 1

你可以尝试这样的：

class PilotAssignment < ActiveRecord::Base 
    belongs_to :ship 
    belongs_to :pilot, polymorphic: true 
end 

class Ship < ActiveRecord::Base 
    # i'm not sure should be there some additional options or not (like as: :pilot) 
    has_many :pilots, through: :pilot_assignments 
    has_many :pilot_assignments 
end 

class Character < ActiveRecord::Base 
    has_many :ships, through: :pilot_assignments 
    has_many :pilot_assignments, as: :pilot 
end 

class Faction < ActiveRecord::Base 
    has_many :ships, through: :pilot_assignments 
    has_many :pilot_assignments, as: :pilot 
end 

也PilotAssignment应包含以下内容：pilot_type，pilot_id