Method _make_extra_froms

lib/sqlalchemy/sql/dml.py:215–248

(
        self,
        statement: DMLWhereBase,
        explicit_froms: Sequence[FromClause] = (),
    )

        ]

    def _make_extra_froms(
        self,
        statement: DMLWhereBase,
        explicit_froms: Sequence[FromClause] = (),
    ) -> Tuple[FromClause, List[FromClause]]:
        froms: List[FromClause] = []

        all_tables = list(sql_util.tables_from_leftmost(statement.table))
        primary_table = all_tables[0]
        seen = {primary_table}

        def _consider_from(
            from_: FromClause, include_surface_selectables: bool = False
        ) -> None:
            if not seen.intersection(from_._cloned_set):
                froms.append(from_)
            seen.update(from_._cloned_set)
            if include_surface_selectables:
                for elem in sql_util.surface_selectables_only(from_):
                    seen.update(elem._cloned_set)

        for from_ in explicit_froms:
            _consider_from(from_, include_surface_selectables=True)

        consider = statement._where_criteria
        if self._dict_parameters:
            consider += tuple(self._dict_parameters.values())

        for crit in consider:
            for item in _from_objects(crit):
                _consider_from(item)

        froms.extend(all_tables[1:])
        return primary_table, froms

    def _process_values(self, statement: ValuesBase) -> None:
        if self._no_parameters: