conradwt

conradwt

Programming Phoenix 1.4: Add category_id to video table (page 121)

On page 103, we perform:

mix phx.gen.html Multimedia Video videos user_id:references:users \
url:string title:string description:text

The above code adds a field, user_id, to the videos tables.

video.ex:

defmodule Rumbl.Multimedia.Video do
  use Ecto.Schema
  import Ecto.Changeset

  schema "videos" do
    field :description, :string
    field :title, :string
    field :url, :string
    field :user_id, :id

    belongs_to :user, Rumbl.Accounts.User
    belongs_to :category, Rumbl.Multimedia.Category

    timestamps()
  end

  @doc false
  def changeset(video, attrs) do
    video
    |> cast(attrs, [:url, :title, :description, :category_id])
    |> validate_required([:url, :title, :description])
  end
end

One page 121, when I attempt to perform:

mix ecto.gen.migration add_category_id_to_video

I’m getting the following error message:

Compiling 1 file (.ex)

== Compilation error in file lib/rumbl/multimedia/video.ex ==
** (ArgumentError) field/association :user_id is already set on schema
    (ecto 3.5.8) lib/ecto/schema.ex:2056: Ecto.Schema.put_struct_field/3
    (ecto 3.5.8) lib/ecto/schema.ex:1809: Ecto.Schema.define_field/4
    (ecto 3.5.8) lib/ecto/schema.ex:1896: Ecto.Schema.__belongs_to__/4
    lib/rumbl/multimedia/video.ex:11: (module)
    (stdlib 3.14) erl_eval.erl:680: :erl_eval.do_apply/6
    (elixir 1.11.3) lib/kernel/parallel_compiler.ex:314: anonymous fn/4 in Kernel.ParallelCompiler.spawn_workers/7

Marked As Solved

conradwt

conradwt

I was able to resolve the issue by removing user_id field from the videos schema. It would be great if the book was updated to show the error caused by having both
field :user_id, :id and belongs_to :user, Rumbl.Accounts.User and providing a resolution.

Where Next?

Popular Pragmatic Bookshelf topics Top

New
belgoros
Following the steps described in Chapter 6 of the book, I’m stuck with running the migration as described on page 84: bundle exec sequel...
New
brianokken
Many tasks_proj/tests directories exist in chapters 2, 3, 5 that have tests that use the custom markers smoke and get, which are not decl...
New
ianwillie
Hello Brian, I have some problems with running the code in your book. I like the style of the book very much and I have learnt a lot as...
New
Alexandr
Hi everyone! There is an error on the page 71 in the book “Programming machine learning from coding to depp learning” P. Perrotta. You c...
New
mikecargal
Title: Hands-On Rust (Chap 8 (Adding a Heads Up Display) It looks like ​.with_simple_console_no_bg​(SCREEN_WIDTH*2, SCREEN_HEIGHT*2...
New
New
AndyDavis3416
@noelrappin Running the webpack dev server, I receive the following warning: ERROR in tsconfig.json TS18003: No inputs were found in c...
New
jonmac
The allprojects block listed on page 245 produces the following error when syncing gradle: “org.gradle.api.GradleScriptException: A prob...
New
jwandekoken
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below: d...
New

Other popular topics Top

PragmaticBookshelf
Take your Go skills to the next level by learning how to design, develop, and deploy a distributed service. Start from the bare essential...
New
New
PragmaticBookshelf
Brace yourself for a fun challenge: build a photorealistic 3D renderer from scratch! In just a couple of weeks, build a ray tracer that r...
New
PragmaticBookshelf
Free and open source software is the default choice for the technologies that run our world, and it’s built and maintained by people like...
New
New
AstonJ
Biggest jackpot ever apparently! :upside_down_face: I don’t (usually) gamble/play the lottery, but working on a program to predict the...
New
hilfordjames
There appears to have been an update that has changed the terminology for what has previously been known as the Taskbar Overflow - this h...
New
PragmaticBookshelf
Author Spotlight: Peter Ullrich @PJUllrich Data is at the core of every business, but it is useless if nobody can access and analyze ...
New
New
RobertRichards
Hair Salon Games for Girls Fun Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
New

Sub Categories: