-spec associations() ->
                      [#kura_assoc{name :: atom(),
                                   type :: belongs_to | has_one | has_many | many_to_many,
                                   schema :: module(),
                                   foreign_key :: atom() | undefined,
                                   ref ::
                                       #kura_ref{fields :: [atom()] | undefined,
                                                 target :: module() | undefined,
                                                 target_key :: [atom()] | undefined} |
                                       undefined,
                                   join_through :: binary() | module() | undefined,
                                   join_keys :: {atom() | [atom()], atom() | [atom()]} | undefined,
                                   through :: [atom()] | undefined,
                                   on_delete :: kura_schema:on_delete() | undefined}].

-spec changeset(map(), map()) ->
                   #kura_changeset{valid :: boolean(),
                                   schema :: module() | undefined,
                                   data :: map(),
                                   params :: map(),
                                   changes :: map(),
                                   errors :: [{atom(), binary()}],
                                   types :: #{atom() => kura_types:kura_type()},
                                   required :: [atom()],
                                   action :: atom() | undefined,
                                   constraints ::
                                       [#kura_constraint{type ::
                                                             unique | foreign_key | check | exclusion,
                                                         constraint :: binary(),
                                                         field :: atom(),
                                                         message :: binary()}],
                                   assoc_changes :: #{atom() => #kura_changeset{} | [#kura_changeset{}]},
                                   prepare :: [fun((#kura_changeset{}) -> #kura_changeset{})],
                                   optimistic_lock :: atom() | undefined}.

-spec fields() ->
                [#kura_field{name :: atom(),
                             type :: kura_types:kura_type(),
                             column :: binary() | undefined,
                             default :: term(),
                             primary_key :: boolean(),
                             nullable :: boolean(),
                             virtual :: boolean()}].

-spec generate_id() -> binary().

-spec table() -> binary().