Virtual models in ecto

Question

Is there a way we can define a virtual model in ecto. Which don't have migration file and don't persist in the data base. I didn't find any documentation related to that in Ecto docs. I need this to test some functions in the iex. To test with models separate from the rest of the app.

I found embedded schema which contain fields that don't persist in the database but nothing related to the models.

Any help will be much appreciated.

Answer 1

Embedded schema is just fine.

defmodule Test.Model do
  @moduledoc ~S"""
  The dummy test model that is not stored in the database.
  """
  use Ecto.Schema
  import Ecto.Changeset

  @type t :: Ecto.Schema.t

  @fields ~w|foo bar baz|a
  @primary_key false

  embedded_schema do
    field :foo, :string
    field :bar, :integer
    field :baz, :float
  end

  def new(data) when is_map(data) do
    %__MODULE__{}
    |> cast(data, @fields)
    |> validate_required(~w|foo|a)
    |> apply_changes()
  end
end

Once defined, it might be used as the normal schema.