Ecto association to more than one schemas

Question

Assuming

schema "infrastructure_instances" do
  belongs_to :provider, MyApp.Infrastructure.Provider
  belongs_to :user, MyApp.Web.User
end

and

schema "infrastructure_providers" do
  belongs_to :user, MyApp.Web.User
  has_many :instances, MyApp.Infrastructure.Instance
end

... and

schema "account_users" do
  has_many :providers, MyApp.Infrastructure.Provider
  has_many :instances, MyApp.Infrastructure.Instance
end

How would i build an association for an Instance to a Provider and a User

This works, but there should certainly be a better way,

def create_instance(attrs \\ %{},user) do
  user
  |> build_assoc(:instances,provider_id: provider_id)

Thank You

Answer 1

build_assoc(user, :instances, provider: provider)

(hopefully it works this way) or

build_assoc(user, :instances, provider_id: provider_id)

seems fine to me. So your way is not that bad I think.

Or maybe this if you need to create a changeset ->

%Instance{}
|> Changeset.change()
|> Changeset.put_assoc(:user, user_struct_or_changeset)
|> Changeset.put_assoc(:provider, provider_struct_or_changeset)