我正在尝试构建一个表来处理某个营销活动已设置为的位置和类别,并具有以下模型关联:
class Campaign < ActiveRecord::Base
has_many :campaign_category_metro_bids, dependent: :destroy
has_many :metros, through: :campaign_category_metro_bids
has_many :categories, through: :campaign_category_metro_bids
end
class Metro < ActiveRecord::Base
has_many :campaign_category_metro_bids
has_many :campaigns, through: :campaign_category_metro_bids
has_many :categories, through: :campaign_category_metro_bids
end
class Category < ActiveRecord::Base
has_many :campaign_category_metro_bids
has_many :campaigns, through: :campaign_category_metro_bids
has_many :metros, through: :campaign_category_metro_bids
end
class CampaignCategoryMetroBid < ActiveRecord::Base
belongs_to :campaign
belongs_to :category
belongs_to :metro
end
当尝试创建一个选择两个不同城市和类别的营销活动时,其中一个参数的 id 结果为 NULL,如下所示:
活动创建代码:
def new
if signed_in?
# create new campaign
@user = User.find(params[:id])
@campaign = @user.campaigns.new
else
redirect_to signin_path
end
end
def create
@campaign = User.find(params["campaign"]["user_id"]).campaigns.build(campaign_params)
if @campaign.save
flash[:success] = "Campaign created!"
redirect_to current_user
else
render 'new'
end
end
UPDATED创建营销活动的视图对 Category 和 Metro 使用两个单独的 collection_select ,如下所示:
<%= f.collection_select :category_ids, Category.all, :id, :display_category, {}, {multiple: true} %>
and
<%= f.collection_select :metro_ids, Metro.all, :id, :full_name, {}, {multiple: true} %>
活动参数:
def campaign_params
params.require(:campaign).permit(:name, :campaign_category_metro_bid_id,
:metro_ids => [], :category_ids => [])
end
当我尝试时,是否有更好的方法来允许创建 3 个表关系?
或链接的方式Category
and Metro
选择模型,以便在创建活动时生成的表格如下所示: