Ecto Changeset: modify column type from :string to {:array, :string}

Questions & Help Questions
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8

Thanks @dimitarvp and @LostKobrakai, here’s what I ended up settling on:

defmodule Database.Repo.Migrations.StringToListMigration do
  use Ecto.Migration

  def change do
    execute(&string_to_list/0, &list_to_string/0)
  end

  defp string_to_list() do
    repo().query!("alter table my_table alter column_name type varchar(255)[] using array[column_name], alter column_name set default '{}';", [], [log: :info])
  end

  defp list_to_string() do
    repo().query!("alter table my_table alter column_name type varchar(255) using column_name[1], alter column_name drop default;", [], [log: :info])
  end
end

I do the renaming / other cleanup operations in a separate migration.