elixir - Ecto.Queryable 未针对用户/Phoenix 错误实现

Question

遵循Programming Phoenix 1.4一书。当我使用手动数据库时，该模块工作正常，但是当我尝试切换我的accounts.ex文件时(就像书上告诉我的那样)，它坏了:

defmodule Rumbl.Accounts do
  alias Rumbl.Repo

  def get_user(id) do
    Repo.get(User, id)
  end

  def get_user!(id) do
    Repo.get!(User, id)
  end

  def get_user_by(params) do
    Repo.get_by(User, params)
  end

  def list_users do
    Repo.all(User)
  end
end

以下是更改 account.ex 文件时出现的完整错误:

[error] #PID<0.732.0> running RumblWeb.Endpoint (connection #PID<0.731.0>, stream id 1) terminated
Server: localhost:4000 (http)
Request: GET /users
** (exit) an exception was raised:
    ** (Protocol.UndefinedError) protocol Ecto.Queryable not implemented for User, the given module does not exist. This protocol is implemented for: Atom, BitString, Ecto.Query, Ecto.SubQuery, Tuple
        (ecto) lib/ecto/queryable.ex:40: Ecto.Queryable.Atom.to_query/1
        (ecto) lib/ecto/repo/queryable.ex:14: Ecto.Repo.Queryable.all/3
        (rumbl) lib/rumbl_web/controllers/user_controller.ex:7: RumblWeb.UserController.index/2
        (rumbl) lib/rumbl_web/controllers/user_controller.ex:1: RumblWeb.UserController.action/2
        (rumbl) lib/rumbl_web/controllers/user_controller.ex:1: RumblWeb.UserController.phoenix_controller_pipeline/2
        (rumbl) lib/rumbl_web/endpoint.ex:1: RumblWeb.Endpoint.instrument/4
        (phoenix) lib/phoenix/router.ex:275: Phoenix.Router.__call__/1
        (rumbl) lib/rumbl_web/endpoint.ex:1: RumblWeb.Endpoint.plug_builder_call/2
        (rumbl) lib/plug/debugger.ex:122: RumblWeb.Endpoint."call (overridable 3)"/2
        (rumbl) lib/rumbl_web/endpoint.ex:1: RumblWeb.Endpoint.call/2
        (phoenix) lib/phoenix/endpoint/cowboy2_handler.ex:34: Phoenix.Endpoint.Cowboy2Handler.init/2

Answer 1

Ecto.Queryable not implemented for User, the given module does not exist.

错误非常明显，这意味着您没有名为 User 的模块(在您的应用程序中可能是 Rumbl.User 或 Rumbl.Accounts.User)。

假设您确实创建了 ecto 模式 Rumbl.User ，你应该:

1. 要么alias它在您使用的模块中:

   alias Rumbl.User
   

2. 或使用模块的完全限定名称:

   Repo.get(Rumbl.User, id)