PragProg Customers

Agile Web Development with Rails 6: LineItem

ncr

ncr

Agile Web Development with Rails 6: LineItem

Hi,
Newbie here trying to learn Ruby on rails with AWDR6. Got a question regarding the LineItem scaffolded as part of Iteration D2: Connecting Products to Carts. What additional value does it provide? Is it just a join table for the many to many relationship between products and carts? But then a has_many association was used instead of has_many: through or has_many_and_belongs to as per docs. I am struggling to understand this bit of the tutorial as I do not get the underlying logic so any help will be highly appreciated

2 comments
#question/book-agile-web-development-with-rails-6
1 690 2

Most Liked

davetron5000

davetron5000

Author of Rails, Angular, Postgres, and Bootstrap

In theory if the join table doesn’t do more than just connect two tables, you are right, you probably would not need to create a model class for it. Iteration D2 doesn’t really foreshadow this, but in Iteration E1, we add a quantity to the line item, and this is a good example of why you’d make a model for the join table - to add metadata about the many-to-many relationship itself.

1
Post #2

Where Next?

View thread on forum
View Agile Web Development With Rails 6's book portal
Post errata for this book
Post a suggestion for this book
Post a question about this book
Post a review about this book
question
Home PragProg Customers
#question/book-agile-web-development-with-rails-6
1 690 2
Last post

Popular Pragmatic Bookshelf topics Top

belgoros
PragProg Customers

Effective Testing with RSpec 3: Running Sequel migrations fails (page 84)
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...
#errata/book-effective-testing-with-rspec-3
4 1152 1
New
brianokken
PragProg Customers

Python Testing with pytest: pytest now requires markers to be declared (downloadable code)
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...
#errata/book-python-testing-with-pytest
2 1383 2
New
GilWright
PragProg Customers

Apple Game Frameworks and Technologies: Screen image may be wrong (p 13)
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...
#errata/book-apple-game-frameworks-and-technologies
11 1081 5
New
patoncrispy
PragProg Customers

Hands-on Rust: Adequate docs for bracket_lib
I’m new to Rust and am using this book to learn more as well as to feed my interest in game dev. I’ve just finished the flappy dragon exa...
#question/book-hands-on-rust
5 1516 3
New
jskubick
PragProg Customers

Kotlin and Android Development featuring Jetpack: Error in generated Game.java (page 136)
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...
#question/book-kotlin-and-android-development-featuring-jetpack
2 1172 8
New
adamwoolhether
PragProg Customers

Powerful Command-Line Applications in Go: Exercise Solutions (many pages)
Is there any place where we can discuss the solutions to some of the exercises? I can figure most of them out, but am having trouble with...
#question/book-powerful-command-line-applications-in-go
17 1396 9
New
taguniversalmachine
PragProg Customers

Real-Time Phoenix: ProductChannelTest - undefined function describe/2 (pg 203)
Hi, I am getting an error I cannot figure out on my test. I have what I think is the exact code from the book, other than I changed “us...
#question/book-real-time-phoenix
0 1775 6
New
kolossal
PragProg Customers

Hands on Rust: Need help with error - thread 'main' panicked at 'Failed to load texture
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...
#question/book-hands-on-rust
3 1989 5
New
Keton
PragProg Customers

Hands-on Rust: How do I debug a call chain in Rust?
When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
#question/book-hands-on-rust
2 1034 2
New
dtonhofer
PragProg Customers

The Definitive ANTLR 4 Reference - "Java.g4" grammer (used on page 40) no longer passes ANTLR
@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....
#errata/book-the-definitive-antlr-4-reference
0 1020 3
New

Other popular topics Top

PragmaticBookshelf
Backend>Learning Resources

Testing Elixir
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...
pragprog.com
#pragprog/elixir#published-book/book-testing-elixir
33 5004 8
New
brentjanderson
General Dev>Hardware

Moonlander Keyboard (Mechanical) (Ergonomic) (Split) (Ortholinear)
Bought the Moonlander mechanical keyboard. Cherry Brown MX switches. Arms and wrists have been hurting enough that it’s time I did someth...
#hardware/keyboards#moonlander#mechanical-keyboards#ortholinear#ergonomic
212 17779 90
New
AstonJ
Backend>Questions

Erlang's not installing on macOS Big Sur "You are natively building Erlang/OTP for a later version of MacOSX than current version"
Just done a fresh install of macOS Big Sur and on installing Erlang I am getting: asdf install erlang 23.1.2 Configure failed. checking ...
#macos/erlang#big-sur#asdf
10 6212 8
New
Exadra37
Linux>Chat

RancherOS is in end of life
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...
#linux#rancheros
10 6358 6
New
DevotionGeo
General Dev>Dev Chat

The V Programming Language
The V Programming Language Simple language for building maintainable programs V is already mentioned couple of times in the forum, but I...
#programminguages/v
21 13874 7
New
Maartz
General Dev>Dev Chat

Roc Language - a new purely functional programming language built for speed and ergonomics
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. ...
#programminguages#functional-programming
49 5164 14
New
PragmaticBookshelf
Backend>Learning Resources

Agile Web Development with Rails 7
Rails 7 completely redefines what it means to produce fantastic user experiences and provides a way to achieve all the benefits of single...
pragprog.com
#pragprog#web-development/ruby/rails#published-book/book-agile-web-development-with-rails-7
32 6600 9
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: Peter Ullrich (Author) Interview and AMA!
Author Spotlight: Peter Ullrich @PJUllrich Data is at the core of every business, but it is useless if nobody can access and analyze ...
/elixir/phoenix/book-building-table-views-with-phoenix-liveview
72 4765 21
New
PragmaticBookshelf
Backend>Learning Resources

Machine Learning in Elixir
Leverage Elixir and the Nx ecosystem to build intelligent applications that solve real-world problems in computer vision, natural languag...
pragprog.com
#pragprog/elixir#published-book#machine-learning#nx/book-machine-learning-in-elixir
18 4615 7
New
AnfaengerAlex
Android>Questions

Unresolved Reference to android in build.gradle.kts – Beginner Issue
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...
#binding
0 7460 2
New
Back to top

Latest in Agile Web Development with Rails 6

Agile Web Development with Rails 6 Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap