Ruby on rails ActiveRecord:：语句无效。SQLite3:：SQLException:没有这样的表

我正在创建一个社交网络，在添加“好友请求”时遇到问题。 当我按下“AddFriend”按钮时，Rails控制台显示以下内容

移民友谊：

class CreateFriendships < ActiveRecord::Migration[5.1]
  def change
    create_table :friendships do |t|
      t.references :user, foreign_key: true
      t.references :friend, foreign_key: true
      t.string :status

      t.timestamps
    end
  end
end

模式：

  create_table "friendships", force: :cascade do |t|
    t.integer "user_id"
    t.integer "friend_id"
    t.string "status"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["friend_id"], name: "index_friendships_on_friend_id"
    t.index ["user_id"], name: "index_friendships_on_user_id"
  end

  create_table "posts", force: :cascade do |t|
    t.text "body"
    t.integer "user_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["user_id"], name: "index_posts_on_user_id"
  end

  create_table "users", force: :cascade do |t|
    t.string "email", default: "", null: false
    t.string "username", default: "", null: false
    t.string "name"
    t.string "last_name"
    t.string "rut", default: "", null: false
    t.string "bio"
    t.string "uid"
    ...
    end

end

轨道：轨道5.1.6

Ruby:Ruby 2.3.1p112（2016-04-26）[x86_64-linux-gnu]

---

有什么想法吗谢谢

您需要更改此迁移。由于外键约束，数据库正在尝试查找id为

friend\u id

class CreateFriendships < ActiveRecord::Migration[5.1]
  def change
    create_table :friendships do |t|
      t.references :user, foreign_key: true
      t.references :friend, foreign_key: true
      t.string :status

      t.timestamps
    end
  end
end

手动添加

add_foreign_key :friendships, :users, column: :friend_id

迁移的最终内容

class CreateFriendships < ActiveRecord::Migration[5.1]
  def change
    create_table :friendships do |t|
      t.references :user, foreign_key: true

      t.references :friend, foreign_key: false
      # OR
      # t.integer :friend_id, index: true #=> Alternative to above line

      t.string :status

      t.timestamps
    end
    add_foreign_key :friendships, :users, column: :friend_id
  end
end

class-CreateFriendships上述行的替代项
t、 字符串：状态
t、 时间戳
结束
添加\外键\友情，：用户，列：：朋友\ id
结束
结束

能否添加完整的模式？@SebastianPalma否，“friend”表不存在。朋友毕竟是用户。@SebastianPalma和no，当尝试控制台时会抛出相同的错误。@TheCretmaster现在是了added@SebastianPalma但是，当以以下方式映射类“属于：朋友，类名称：”用户“”时，我没有以正确的方式进行引用：C

  create_table "friendships", force: :cascade do |t|
    t.integer "user_id"
    t.integer "friend_id"
    t.string "status"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["friend_id"], name: "index_friendships_on_friend_id"
    t.index ["user_id"], name: "index_friendships_on_user_id"
  end

  create_table "posts", force: :cascade do |t|
    t.text "body"
    t.integer "user_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["user_id"], name: "index_posts_on_user_id"
  end

  create_table "users", force: :cascade do |t|
    t.string "email", default: "", null: false
    t.string "username", default: "", null: false
    t.string "name"
    t.string "last_name"
    t.string "rut", default: "", null: false
    t.string "bio"
    t.string "uid"
    ...
    end

end

class CreateFriendships < ActiveRecord::Migration[5.1]
  def change
    create_table :friendships do |t|
      t.references :user, foreign_key: true
      t.references :friend, foreign_key: true
      t.string :status

      t.timestamps
    end
  end
end

t.references :friend, foreign_key: false

add_foreign_key :friendships, :users, column: :friend_id

class CreateFriendships < ActiveRecord::Migration[5.1]
  def change
    create_table :friendships do |t|
      t.references :user, foreign_key: true

      t.references :friend, foreign_key: false
      # OR
      # t.integer :friend_id, index: true #=> Alternative to above line

      t.string :status

      t.timestamps
    end
    add_foreign_key :friendships, :users, column: :friend_id
  end
end