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
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.
Popular Pragmatic Bookshelf topics
As per the title, thanks.
New
Working through the steps (checking that the Info,plist matches exactly), run the demo game and what appears is grey but does not fill th...
New
Title: Hands-on Rust: question about get_component (page 295)
(feel free to respond. “You dug you’re own hole… good luck”)
I have somet...
New
Hi @Margaret ,
On page VII the book tells us the example and snippets will be all using Elixir version 1.11
But on page 3 almost the en...
New
The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...
New
Running mix deps.get in the sensor_hub directory fails with the following error:
** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...
New
I’m running Android Studio “Arctic Fox” 2020.3.1 Patch 2, and I’m embarrassed to admit that I only made it to page 8 before running into ...
New
@parrt
In the context of Chapter 4.3, the grammar Java.g4, meant to parse Java 6 compilation units, no longer passes ANTLR (currently 4....
New
Getting an error when installing the dependencies at the start of this chapter:
could not compile dependency :exla, "mix compile" failed...
New
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
New
Other popular topics
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
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
New
There’s a whole world of custom keycaps out there that I didn’t know existed!
Check out all of our Keycaps threads here:
https://forum....
New
This looks like a stunning keycap set :orange_heart:
A LEGENDARY KEYBOARD LIVES ON
When you bought an Apple Macintosh computer in the e...
New
Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...
New
Learn different ways of writing concurrent code in Elixir and increase your application's performance, without sacrificing scalability or...
New
Hi folks,
I don’t know if I saw this here but, here’s a new programming language, called Roc
Reminds me a bit of Elm and thus Haskell. ...
New
Author Spotlight
Jamis Buck
@jamis
This month, we have the pleasure of spotlighting author Jamis Buck, who has written Mazes for Prog...
New
Author Spotlight
Mike Riley
@mriley
This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
New
Author Spotlight:
VM Brasseur
@vmbrasseur
We have a treat for you today! We turn the spotlight onto Open Source as we sit down with V...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /java
- /emacs
- /haskell
- /typescript
- /svelte
- /onivim
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /vscode
- /flutter
- /ash
- /html
- /deepseek
- /opensuse
- /zig
- /centos
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /deno
- /django
- /kubuntu
- /arch-linux
- /nodejs
- /ubuntu
- /spring
- /revery
- /manjaro
- /lua
- /diversity
- /julia
- /laravel
- /quarkus









