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
This test is broken right out of the box…
— FAIL: TestAgent (7.82s)
agent_test.go:77:
Error Trace: agent_test.go:77
agent_test.go:...
New
The following is cross-posted from the original Ray Tracer Challenge forum, from a post by garfieldnate. I’m cross-posting it so that the...
New
I’m under the impression that when the reader gets to page 136 (“View Data with the Database Inspector”), the code SHOULD be able to buil...
New
The markup used to display the uploaded image results in a Phoenix.LiveView.HTMLTokenizer.ParseError error.
lib/pento_web/live/product_l...
New
Skimming ahead, much of the following is explained in Chapter 3, but new readers (like me!) will hit a roadblock in Chapter 2 with their ...
New
Hi, I need some help, I’m new to rust and was learning through your book. but I got stuck at the last stage of distribution. Whenever I t...
New
Modern Front-End Development for Rails - application does not start after run bin/setup (page xviii)
After some hassle, I was able to finally run bin/setup, now I have started the rails server but I get this error message right when I vis...
New
I am using Android Studio Chipmunk | 2021.2.1 Patch 2
Build #AI-212.5712.43.2112.8815526, built on July 10, 2022
Runtime version: 11.0....
New
Hello @herbert ! Trying to get the very first “Hello, Bracket Terminal!" example to run (p. 53). I develop on an Amazon EC2 instance runn...
New
Disclaimer: I hope all of this is accurate, and not the result of some stupid typo I failed to notice. Anyways…
This post comprises 2 is...
New
Other popular topics
Design and develop sophisticated 2D games that are as much fun to make as they are to play. From particle effects and pathfinding to soci...
New
Bought the Moonlander mechanical keyboard. Cherry Brown MX switches. Arms and wrists have been hurting enough that it’s time I did someth...
New
You might be thinking we should just ask who’s not using VSCode :joy: however there are some new additions in the space that might give V...
New
Rust is an exciting new programming language combining the power of C with memory safety, fearless concurrency, and productivity boosters...
New
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me.
I think the Planck and the Preonic (o...
New
Small essay with thoughts on macOS vs. Linux:
I know @Exadra37 is just waiting around the corner to scream at me “I TOLD YOU SO!!!” but I...
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
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
New
Jan | Rethink the Computer.
Jan turns your computer into an AI machine by running LLMs locally on your computer. It’s a privacy-focus, l...
New
Hello,
I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /java
- /clojure
- /typescript
- /emacs
- /haskell
- /svelte
- /onivim
- /kotlin
- /react
- /c-plus-plus
- /crystal
- /tailwind
- /gleam
- /ocaml
- /elm
- /vscode
- /flutter
- /html
- /ash
- /deepseek
- /zig
- /opensuse
- /centos
- /php
- /react-native
- /scala
- /lisp
- /textmate
- /sublime-text
- /debian
- /nixos
- /agda
- /deno
- /django
- /kubuntu
- /nodejs
- /arch-linux
- /spring
- /ubuntu
- /revery
- /manjaro
- /julia
- /lua
- /diversity
- /quarkus
- /markdown









