Saving many entries from a form at once

Why do you think you cannot create one? It could even live just in the controller/live view rendering your form.

I believe I’m trying this approach with the MailingList embedded schema here. The thing is that I want to insert/update/delete only the changeset list of emails. Given I can grab it with get_embed(mailing_list, :emails), I tried iterating over the list of emails and applying them to the DB, but I could not figure out how to apply them back in the MailingList changeset.

Is having a MailingList embedded schema what you had in mind?

Have you tried put_embed/4 from Ecto.Changeset — Ecto v3.14.0?

Yes, I have. I think the form wasn’t behaving correctly when I tried it because I was calling put_embed after the changesets being applied to the DB, which caused them to have the action replace and it left the form in a wrong state.

I guess I found a workaround for that, which is to reinitialise the original changeset instead of trying to update it after applying the operations to the DB. The code is something like this now:

def save(changeset) do
  emails_changesets = get_embed(changeset, :emails)

  case apply_changesets(emails_changesets) do
    {:ok, emails_list} -> {:ok, MailingList.changeset(%MailingList{emails: emails_list})}
    {:error, emails_changesets} -> {:error, put_embed(changeset, :emails, emails_changesets)}
  end
end