Rails Unpermitted parameters: topic_ids
我有一个多对多关系 Explaination 和 Topic，创建 Explaination 绑定若干 Topics，其他的都对了，就是这个关联一直绑不上，日志说 Unpermitted parameters: topic_ids，请问这是啥情况，知道请指点，谢啦先！
我的 Controller 是这样写的
def create
params.permit!
@place = Place.find(params[:place_id])
@explaination = @place.explainations.create(params[:explaination].permit(:title, :speaker, :speaker_title, :like, :topic_ids))
@explaination.save
redirect_to @place
end
其他相关代码如下
class Explaination < ActiveRecord::Base
belongs_to :place
has_many :explaination_segments, :dependent => :destroy
has_and_belongs_to_many :topics
def segments
self.explaination_segments
end
end
class Topic < ActiveRecord::Base
belongs_to :place
has_and_belongs_to_many :explainations
end
create_table "explainations_topics", force: true do |t|
t.integer "explaination_id"
t.integer "topic_id"
t.datetime "created_at"
t.datetime "updated_at"
end
#1 楼 @themorecolor 多谢指点，不过多 save 一次也不致错 我改成这样，就可以了
def create
params.permit!
@place = Place.find(params[:place_id])
@explaination = @place.explainations.create(params[:explaination].permit(:title, :speaker, :speaker_title, :like))
@explaination.topic_ids = params[:explaination][:topic_ids]
@explaination.save
redirect_to @place
end
我猜测，在 create 那一句，explaination 的 id 还没有确定，无法同时往 explainations_topics 插入记录。必须得先把 explaination 生成了，再往他身上绑 topics。
@explaination = @place.explainations.create(params.require(:explaination).permit(:title, :speaker, :speaker_title, :like, topic_ids: []))
