Hello people! As a part of my elixir learning curve, I am working on the sneaker store application. I am struggling with displaying all sizes for each model. I was reading about Ecto.Multi but i don’t know if I’m going in the good direction. Another thing i do not know how to start with is adding available sizes for the exact model.
What I’d like to achieve is:
- For each shoe model (from the product table) display all available sizes and quantity of each size from the stock table.
- When adding a new shoe model, add sizes + quantity of each size in one go, so the admin doesn’t need to add each size and quantity separately for each shoe pair.
I will appreciate any help or guide in which direction I should go.
I think it would help if you share how your db schema looks like.
This should be straightforward if you have for example a “shoes” table, with a “size” and “quantity” rows. Maybe having a composite unique index between model and size.
EDIT: About your no. 2. That sounds like a UI feature
I guess I might mess up with my database design then…
I got two tables:
schema "products" do
field :colour, :string
field :description, :string
field :name, :string
field :price, :decimal
field :product_code, :string
field :release_year, :integer
belongs_to :category, Jordaniva.Categories.Category
belongs_to :subcategory, Jordaniva.Categories.Subcategory
has_many :items, Jordaniva.Inventory.Item
schema "items" do
field :quantity, :integer
field :size, :decimal
belongs_to :product, Jordaniva.Inventory.Product
So looks like you can do it with something like:
# Get products
# Item from product
Repo.get_by(Item, product_id: product_id)
# Both at the same time
Repo.get(Product, product_id) |> Repo.preload(:items)
p in Product,
where: p.id == ^product_id,
# pagination logic...
You can read more about it here: https://hexdocs.pm/ecto/Ecto.Query.html#preload/3
And for your number 2: https://hexdocs.pm/ecto/Ecto.Changeset.html#put_assoc/4 or https://hexdocs.pm/ecto/Ecto.Changeset.html#cast_assoc/3
Here there’s a good article about it: http://blog.plataformatec.com.br/2015/08/working-with-ecto-associations-and-embeds/ and a convo Confussed with build_assoc vs put_assoc vs cast_assoc
Thank you! I will take a look into that.