Ruby on rails 多元关联，并且有很多：通过在试图获取关联记录时生成错误的sql，rails？

为了说明这一点，我创建了一个多态的

标记
关联，它属于
microspost
和
标记

编辑的标记模型错误

class Tagging < ApplicationRecord

  belongs_to :tag, inverse_of: :taggings
  belongs_to :taggable, polymorphic: true
...


它将
tag_id
放入
taggable_id
中，该id实际上应该是micropost id，因此给出空数组

我的怀疑是，正如您在生成的sql中所看到的，它显示了
[“taggable_类型”，“Tag”]，[“taggable_类型”，“Micropost”]
其中
Tag
taggable_类型不应该存在，但我不知道如何摆脱它

为清晰起见，我添加了编辑模式

create_table "taggings", force: :cascade do |t|
  t.string "taggable_type"
  t.bigint "taggable_id"
  t.bigint "tag_id"
  t.string "topic"
  t.datetime "created_at", precision: 6, null: false
  t.datetime "updated_at", precision: 6, null: false
  t.index ["tag_id"], name: "index_taggings_on_tag_id"
  t.index ["taggable_type", "taggable_id"], name: "index_taggings_on_taggable_type_and_taggable_id"
  t.index ["topic"], name: "index_taggings_on_topic"
end

create_table "tags", force: :cascade do |t|
  t.string "name"
  t.datetime "created_at", precision: 6, null: false
  t.datetime "updated_at", precision: 6, null: false
  t.index ["name"], name: "index_tags_on_name"
end

所以丢失了。
更改标记中的关系

类标记

具有其他模型id列的模型属于该模型。

ER模型如下所示：

Micropost ---------> Tagging <------------ Tag
                   :taggable_type
                   :taggable_id
                   :tag_id

microspost-------->标记OK。我意识到我已经在
标签中定义了这个模型

has_many :taggings, as: :taggable, inverse_of: :taggable

应该是

has_many :taggings

因为我们需要tags.taggings而不是tag.taggings作为taggable，它现在将查询
tag\u id
，并为tag.microspots生成正确的sql

Thnx
等等，我把代码搞糟了，我重新编辑了
标签
模型
<Tag id: 10, name: "hello", created_at: "2020-04-01 08:39:36", updated_at: "2020-04-01 08:39:36">

tag.microposts
Micropost Load (0.4ms)  SELECT "microposts".* FROM "microposts" INNER JOIN "taggings" ON "microposts"."id" = "taggings"."taggable_id" WHERE "taggings"."taggable_id" = $1 AND "taggings"."taggable_type" = $2 AND "taggings"."taggable_type" = $3 LIMIT $4  [["taggable_id", 10], ["taggable_type", "Tag"], ["taggable_type", "Micropost"], ["LIMIT", 11]]
=> <ActiveRecord::Associations::CollectionProxy []>

create_table "taggings", force: :cascade do |t|
  t.string "taggable_type"
  t.bigint "taggable_id"
  t.bigint "tag_id"
  t.string "topic"
  t.datetime "created_at", precision: 6, null: false
  t.datetime "updated_at", precision: 6, null: false
  t.index ["tag_id"], name: "index_taggings_on_tag_id"
  t.index ["taggable_type", "taggable_id"], name: "index_taggings_on_taggable_type_and_taggable_id"
  t.index ["topic"], name: "index_taggings_on_topic"
end

create_table "tags", force: :cascade do |t|
  t.string "name"
  t.datetime "created_at", precision: 6, null: false
  t.datetime "updated_at", precision: 6, null: false
  t.index ["name"], name: "index_tags_on_name"
end

Micropost ---------> Tagging <------------ Tag
                   :taggable_type
                   :taggable_id
                   :tag_id

has_many :taggings, as: :taggable, inverse_of: :taggable

has_many :taggings