Programming Ecto

Capturing Errors

The last step of the process is sending our changeset to Repo and seeing what happens. In this section, we’ll see how changesets help us track errors and report them to the user.

Looking back at our example from the beginning of the chapter, we can see the entire changeset workflow:

priv/examples/changeset_07.exs

params = %{name: "Gene Harris"}
changeset =
  %Artist{}
  |> cast(params, [:name])
  |> validate_required([:name])

case Repo.insert(changeset) do
  {:ok, artist} -> IO.puts("Record for #{artist.name} was created.")
  {:error, changeset} -> IO.inspect(changeset.errors)
end

This is how we handle inserting a new record (if we were updating an ...