AE
Ash Elixir•3y ago
Ybireder

Additional attributes in many-to-many relations

Hi there, I'm using a many-to-many relation between two resources. The resources Ingredient and Store are related through the resource Price (an ingredient is available at a store for a certain price). The Price resource has the additional attributes :amount and :price. Ideally, I'd like to have an action on the Ingredient resource to add a store. Somewhat like this: 
    update :add_store do
      argument :store_id, :string, allow_nil?: false
      argument :amount, :float
      argument :price, :int
      ...
    end
    update :add_store do
      argument :store_id, :string, allow_nil?: false
      argument :amount, :float
      argument :price, :int
      ...
    end
This action should create a new price with the given attributes, but I'm struggling to implement the action. On other many-to-many relations, I've used change manage_relationship(:stores, type: :append) but I can't figure out how to add the additional arguments.
1 Reply
ZachDaniel
ZachDaniel•3y ago
Hey there! Been a bit busy today, but what you’re looking for is the more specific instructions that you can use for manage_relationship For example: on_no_match: {:update, :update, :update, [:join, :fields]} Check out the docs for Ash.Changeset.manage_relationship Additionally, you can manage the join relationship instead of the many to many relationship.

Did you find this page helpful?