uuid_primary_key unwraps into:Ash.UUID.generate/0 seems to be a passthrough to Ecto.UUID.generate(). What I found unexpected was the migration files.:binary, :binary_id, and :uuid similarly when ran by Ecto SQL, but I'm not sure.:default option in Ash's implementation. It hard-codes a Postgres DB function as a default value even though :primary_key option is set (which I think inherently makes the field non-nullable in most databases.