sqlalchemy.util topological Example Code

# batch.py
from sqlalchemy import CheckConstraint
from sqlalchemy import Column
from sqlalchemy import ForeignKeyConstraint
from sqlalchemy import Index
from sqlalchemy import MetaData
from sqlalchemy import PrimaryKeyConstraint
from sqlalchemy import schema as sql_schema
from sqlalchemy import select
from sqlalchemy import Table
from sqlalchemy import types as sqltypes
from sqlalchemy.events import SchemaEventTarget
from sqlalchemy.util import OrderedDict
from sqlalchemy.util import topological

from ..util import exc
from ..util.sqla_compat import _columns_for_constraint
from ..util.sqla_compat import _fk_is_self_referential
from ..util.sqla_compat import _is_type_bound
from ..util.sqla_compat import _remove_column_from_collection


class BatchOperationsImpl(object):
    def __init__(
        self,
        operations,
        table_name,
        schema,
        recreate,
        copy_from,
        table_args,
        table_kwargs,
        reflect_args,
        reflect_kwargs,
        naming_convention,
        partial_reordering,
    ):
        self.operations = operations


## ... source file abbreviated to get to topological examples ...


            self.indexes[idx.name] = idx

        for k in self.table.kwargs:
            self.table_kwargs.setdefault(k, self.table.kwargs[k])

    def _adjust_self_columns_for_partial_reordering(self):
        pairs = set()

        col_by_idx = list(self.columns)

        if self.partial_reordering:
            for tuple_ in self.partial_reordering:
                for index, elem in enumerate(tuple_):
                    if index > 0:
                        pairs.add((tuple_[index - 1], elem))
        else:
            for index, elem in enumerate(self.existing_ordering):
                if index > 0:
                    pairs.add((col_by_idx[index - 1], elem))

        pairs.update(self.add_col_ordering)

        pairs = [p for p in pairs if p[0] != p[1]]

        sorted_ = list(
            topological.sort(pairs, col_by_idx, deterministic_order=True)
        )
        self.columns = OrderedDict((k, self.columns[k]) for k in sorted_)
        self.column_transfers = OrderedDict(
            (k, self.column_transfers[k]) for k in sorted_
        )

    def _transfer_elements_to_new_table(self):
        assert self.new_table is None, "Can only create new table once"

        m = MetaData()
        schema = self.table.schema

        if self.partial_reordering or self.add_col_ordering:
            self._adjust_self_columns_for_partial_reordering()

        self.new_table = new_table = Table(
            self.temp_table_name,
            m,
            *(list(self.columns.values()) + list(self.table_args)),
            schema=schema,
            **self.table_kwargs
        )

        for const in (


## ... source file continues with no further topological examples...