I vaguely remember that you can copy the Phoenix source file /priv/templates/phx.gen.schema/schema.ex to your own project and edit the file and this version will be used by the generators.

I couldn’t find docs, but I dug a bit deeper into the source and found that the helper module for the Phoenix generator tasks includes this function phoenix/lib/mix/phoenix.ex at v1.5.11 · phoenixframework/phoenix · GitHub

Which suggests you can copy the schema.ex, make your edit and future generators will use it. It’s worth a try.

Hey Jonathan,

When you run a generator like phx.gen.context the content is obtained from a template. You can find the template in Phoenix’s source at /priv/templates/phx.gen.schema/schema.ex. When the generator is run, there is dynamic content generated such as the module name, fields, etc. But use Ecto.Schema is not a dynamically generated. Check it out:

# /priv/templates/phg.gen.schema/schema.ex

defmodule <%= inspect schema.module %> do
  use Ecto.Schema
  import Ecto.Changeset
<%= if schema.prefix do %>
  @schema_prefix :<%= schema.prefix %><% end %><%= if schema.binary_id do %>
  @primary_key {:id, :binary_id, autogenerate: true}
  @foreign_key_type :binary_id<% end %>
  schema <%= inspect schema.table %> do
<%= for {k, v} <- schema.types do %>    field <%= inspect k %>, <%= Mix.Phoenix.Schema.type_and_opts_for_schema(v) %><%= schema.defaults[k] %><%= Mix.Phoenix.Schema.maybe_redact_field(k in schema.redacts) %>
<% end %><%= for {_, k, _, _} <- schema.assocs do %>    field <%= inspect k %>, <%= if schema.binary_id do %>:binary_id<% else %>:id<% end %>
<% end %>
    timestamps()
  end

  @doc false
  def changeset(<%= schema.singular %>, attrs) do
    <%= schema.singular %>
    |> cast(attrs, [<%= Enum.map_join(schema.attrs, ", ", &inspect(elem(&1, 0))) %>])
    |> validate_required([<%= Enum.map_join(schema.attrs, ", ", &inspect(elem(&1, 0))) %>])
<%= for k <- schema.uniques do %>    |> unique_constraint(<%= inspect k %>)
<% end %>  end
end

You can check out the above source here.

So, to answer your question:

There is no configuration variable or command line argument that will achieve what you’re looking for. Some of your options may be:

• Edit as you generate,
• Automate the changes within your editor or a command line program like sed, or
• Clone Phoenix and then edit the templates. You can then generate/move your project as you would if creating a project from an unreleased version. ← this seems messy to me.

If I was in your position, I would create an interactive Emacs command to take care of renaming Ecto.Schema to MyApp.Schema after generating a schema.