我有与此处描述的完全模式相同的多态连接表:
http://aaronvb.com/articles/a-polymorphic-join-table.html
class Location < ActiveRecord::Base has_many :note_joins,as: :notable has_many :notes,through: :note_joins end class Checkpoint < ActiveRecord::Base has_many :note_joins,through: :note_joins end class NoteJoin < ActiveRecord::Base belongs_to :notable,polymorphic: true belongs_to :note end class Note < ActiveRecord::Base attr_accessible :content,:user_id belongs_to :notable,polymorphic: true belongs_to :user has_many :note_joins end
我希望能够一次创建和更新多种类型的多态关联,而不必执行@ note.locations<< Location.first或@ note.checkpoints<< Checkpoint.first. 像@ note.create note_joins_params和@ note.update note_joins_params这样的东西真棒. 到目前为止,我能够实现创建部分的方法是将一组属性传递给@ note.note_joins.create,例如: :
note_joins_params = [{"notable_id"=>"9225","notable_type"=>"Location"},{"notable_id"=>"9220","notable_type"=>"Checkpoint"}] @note.note_joins.create note_joins_params
是否有更多的Rails方式来实现这一点,或者类似于accepts_nested_attributes或类似的适当属性哈希语法?
我知道如何进行更新的唯一方法是首先删除连接表中的所有现有记录,然后重新创建它们,即
@note.note_joins.destroy_all new_note_joins_params = [{"notable_id"=>"9225","notable_type"=>"Checkpoint"}] @note.note_joins.create new_note_joins_params
解决方法
对于您想要完成的任务,如果您未指定source_type,则Rails实际上没有接受嵌套属性的“smart_way”.请参阅此
The other side of polymorphic :through associations
但你可以试试这个:
class Location < ActiveRecord::Base has_many :note_joins,through: :note_joins accepts_nested_attributes_for :notes end class Checkpoint < ActiveRecord::Base has_many :note_joins,through: :note_joins accepts_nested_attributes_for :notes end class NoteJoin < ActiveRecord::Base belongs_to :notable,polymorphic: true belongs_to :note accepts_nested_attribute_for :note end class Note < ActiveRecord::Base attr_accessible :content,:user_id belongs_to :user has_many :note_joins # add these,otherwise you won't be able to do nested attributes # refer to the blog post I link above. has_many :locations,through: :note_joins,source: :notable,source_type: 'Location' has_many :checkpoints,source_type: 'Checkpoint' end
然后在你的表单中,构建这样的东西:
# In your form # if you want to create from the note,do this <%= form_for @note do |f| %> <%= f.text_field :some_note_field %> <%= text_field_tag 'note[locations_attributes][][some_location_field]' %> <%= text_field_tag 'note[checkpoints_attributes][]some_checkpoint_field]' %> <% end %> # if you want to create from the location/checkpoint,do this. <%= form_for @location do |f| %> <%= f.text_field :name %> <%= text_field_tag 'location[notes_attributes][][body]' %> <% end %> # In your Location/Checkpoint controllers def create @location = Location.create(location_params) redirect_to @location end def location_params params.required(:location).permit(:name,notes_attributes: [:body]) end # In your Note controller def create @note = Note.create(note_params) redirect_to @note end def note_params # the goal here is to create a set of params like this # { note_field: 'foobar',# locations_attributes: [{name: 'somewhere'}],# checkpoints_attributes: [{description: 'lol'}] } params.required(:note).permit(:note_field,locations_attributes: [:location_field],checkpoints_attributes: [:checkpoint_field]) end