I have a relational setup that I would like to just give me an {:error, changeset} tuple back for when the foreign record doesn't exist. However, no matter what I put I always get this error:

14:02:56.563 [error] Task #PID<0.559.0> started from #PID<0.557.0> terminating
** (Ecto.ConstraintError) constraint error when attempting to insert struct:

    *  (foreign_key_constraint)

If you would like to stop this constraint violation from raising an
exception and instead add it as an error to your changeset, please
call `foreign_key_constraint/3` on your changeset with the constraint
`:name` as an option.

The changeset defined the following constraints:

    * intervals_schedule_id_fkey (foreign_key_constraint)

...

If I'm understanding right, SQLite knows there is a constraint here, but its unnamed and so all we get back to help is an empty * (foreign_key_constraint) clue. And since there is no name to match on, Ecto can't reconcile it and things just crash. I've even tried using the name: "" option, but I think Ecto just ignores the empty string.

Is it even possible to get around this or are we limited by the abilities of SQLite here? I do understand I can use the foreign_key: :off option in the adapter to just skip validations entirely which is currently my workaround, but I would love to get the {:error, changeset} return instead.

Caveat: I am in no way a DB expert and this could be 100% user error. My migrations are simple and would love to know if Im just doing things wrong:

create table(:schedules) do
  add :name, :string
end

create table(:intervals) do
  add :schedule, references(:schedules)
end