How Ecto.insert(..., returning: ...) works

Questions & Help Questions
1

I’m wondering if I understand the Ecto.insert :returning option. Here’s how I think it works when inserting a changeset (and possibly a schema struct - I haven’t checked):

  1. Regardless of :returning, the input :data is returned, including virtual fields.
  2. Regardless of :returning, the primary key is always added to that result.

Is that right?

Here’s some code:

      Enum.at(@changesets, 0)
      |> Crit.Repo.insert(prefix: "demo", returning: false)
      |> IO.inspect

The return value is this:

{:ok,
 %Crit.Usables.ServiceGap{
   __meta__: #Ecto.Schema.Metadata<:loaded, "demo", "service_gaps">,
   end_date: nil,
   gap: %Ecto.Datespan{
     first: :unbound,
     last: ~D[2012-12-12],
     lower_inclusive: false,
     upper_inclusive: false
   },
   id: 1236,
   reason: "before animal was put in service",
   start_date: ~D[2012-12-12],
   timezone: nil
 }}

This is the same result as happens with returning: true or returning: [:id].

(I picked a schema without timestamps, because it was the most convenient. I’m betting I could affect whether timestamps were returned with :returning. I’m nearly out of power. I’ll check if my understanding above is wrong.)