freewebwithme
Product and Category relation in Database?
Hello.
I am lost whileI am working on database design. So I need your help. 
It might be simple but I can’t figure it out.
What I want to do is Product and Category relation
Product has 1 category.
Category has many products.
So I can do like this
product = Repo.one(from p in Product, preload: [:category])
product.category.name
query = from p in Product,
join: c in Category,
on: c.name == "Food",
select: p
So I can get products that has “Food” category.
Which relation should I use?
one to many?
Marked As Solved
kokolegorille
Yes, one to many with Product holding a category_id field.
Product belongs_to :category, Category...
Category has_many :products, Product...
But your join is not functional, maybe like this (not tested)
query = from p in Product,
join: c in Category,
on: p.category_id == c.id,
where: c.name == "Food",
select: p
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Supporting innovation across the BEAM ecosystem.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #deployment
- #library
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #channels
- #elixirconf
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #blog-post
- #graphql
- #genstage
- #ai
- #websockets
- #supervisor
- #advent-of-code
- #elixirconf-us
- #distillery
- #processes
- #forms
- #api
- #metaprogramming
- #security
- #performance
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Real-time error tracking, performance insights, and observability for devs.
Practical resources that improve the lives of professional developers.
Enabling companies to succeed by building software people love.
The deployment platform built for Elixir: PaaS ease, VPS control.
Courses that'll move you from confusion to "Aha, now I get it!"