I’m trying to set up the usual many-to-many relationship between two schemas: User and BreadDay. However, the primary key on the bread_day table is day rather than id.
This Problem seemed the same as this post Issue with a `many_to_many` assoc and `join_keys` except that I am not joining the tables through a schema but with a join table.
What I have so far is the following:

#bread_day.ex
@primary_key {:day, :date, autogenerate: false}
schema “bread_days” do
many_to_many :users, User,
join_through: “user_bread_days”,
join_keys: [bread_day_day: :day, user_id: :id]

timestamps(type: :utc_datetime)

end

#user.ex
schema “users” do
field :email, :string
field :password, :string, virtual: true, redact: true
field :hashed_password, :string, redact: true
field :confirmed_at, :naive_datetime

many_to_many :bread_days, BreadDay,
  join_through: "user_bread_days",
  join_keys: [user_id: :id, bread_day_day: :day]

timestamps(type: :utc_datetime)

end

the join table in the migrations:

def change do
create table(“user_bread_days”, primary_key: false) do
add :user_id, references(:users, on_delete: :delete_all)
add :bread_day_day, references(:bread_days, on_delete: :delete_all)
end

and this is the error :
** (Postgrex.Error) ERROR 42703 (undefined_column) Column “id”, which is used in the foreign key, does not exist
(ecto_sql 3.11.0) lib/ecto/adapters/sql.ex:1054: Ecto.Adapters.SQL.raise_sql_call_error/1
(elixir 1.15.6) lib/enum.ex:1693: Enum.“-map/2-lists^map/1-1-”/2
(ecto_sql 3.11.0) lib/ecto/adapters/sql.ex:1161: Ecto.Adapters.SQL.execute_ddl/4
(ecto_sql 3.11.0) lib/ecto/migration/runner.ex:348: Ecto.Migration.Runner.log_and_execute_ddl/3
(elixir 1.15.6) lib/enum.ex:1693: Enum.“-map/2-lists^map/1-1-”/2
(ecto_sql 3.11.0) lib/ecto/migration/runner.ex:311: Ecto.Migration.Runner.perform_operation/3
(stdlib 5.1.1) timer.erl:270: :timer.tc/2
(ecto_sql 3.11.0) lib/ecto/migration/runner.ex:25: Ecto.Migration.Runner.run/8

Any Idea ?