Elixir Ecto: Using a Pivot Attribute in a Many To Many Relationship

Question

I am currently having troubles figuring out how to use pivot attributes in an Ecto many-to-many relationship.

I found the following question but unfortunately nobody had an answer: https://stackoverflow.com/questions/37158184/elixir-ecto-pivot-many-to-many-table-attributes

Basically I need the same setup as mentioned in the question. Two models and I need to store data to the pivot entry.

Has anybody a solution for this problem?

Thanks in advance!

Answer 1

I am doing something like the following in one of my applications

def Foo do
  schema "foos" do
    field :name, :string

    has_many :bars_foos
  end
end

def Bar do
  schema "bars" do
    field :other, :integer

    has_many :bars_foos
  end
end

def BarFoo do
  schema "bars_foos" do
    field :size, :integer

    belongs_to :bars
    belongs_to :foos
  end
end

This uses has_many and belongs_to instead of many_to_many, but it accomplishes something very similar. You can also still use the many_to_many with through if you need a direct link to the other dataset.