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
In Chapter 3, the source for index introduces Config on page 31, followed by more code including tests; Config isn’t introduced until pag...
New
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list)
Typo:...
New
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
Page 28: It implements io.ReaderAt on the store type.
Sorry if it’s a dumb question but was the io.ReaderAt supposed to be io.ReadAt?
...
New
A Common-Sense Guide to Data Structures and Algorithms, Second Edition by Jay Wengrow @jaywengrow
Hi,
I have the paperback version of t...
New
When trying to generate the protobuf .go file, I receive this error:
Unknown flag: --go_opt
libprotoc 3.12.3
MacOS 11.3.1
Googling ...
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
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
@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
Other popular topics
Machine learning can be intimidating, with its reliance on math and algorithms that most programmers don't encounter in their regular wor...
New
Write Elixir tests that you can be proud of. Dive into Elixir’s test philosophy and gain mastery over the terminology and concepts that u...
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
Do the test and post your score :nerd_face:
:keyboard:
If possible, please add info such as the keyboard you’re using, the layout (Qw...
New
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
New
I have always used antique keyboards like Cherry MX 1800 or Cherry MX 8100 and almost always have modified the switches in some way, like...
New
zig/http.zig at 7cf2cbb33ef34c1d211135f56d30fe23b6cacd42 · ziglang/zig.
General-purpose programming language and toolchain for maintaini...
New
Get the comprehensive, insider information you need for Rails 8 with the new edition of this award-winning classic.
Sam Ruby @rubys
...
New
Overarching tutorial for Python beginner and intermediate developers that teaches web development with the Flask framework.
Miguel Gr...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /java
- /clojure
- /emacs
- /typescript
- /haskell
- /svelte
- /onivim
- /kotlin
- /c-plus-plus
- /react
- /crystal
- /tailwind
- /gleam
- /ocaml
- /elm
- /vscode
- /flutter
- /html
- /ash
- /deepseek
- /zig
- /opensuse
- /centos
- /php
- /react-native
- /scala
- /lisp
- /sublime-text
- /textmate
- /debian
- /nixos
- /agda
- /deno
- /django
- /kubuntu
- /arch-linux
- /nodejs
- /spring
- /ubuntu
- /revery
- /manjaro
- /julia
- /lua
- /diversity
- /quarkus
- /markdown









