two version of R2R are here HEAD master

1 files changed, 3371 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py b/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py
new file mode 100644
index 00000000..cbf11acf
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py
@@ -0,0 +1,3371 @@
+# engine/base.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+"""Defines :class:`_engine.Connection` and :class:`_engine.Engine`.
+
+"""
+from __future__ import annotations
+
+import contextlib
+import sys
+import typing
+from typing import Any
+from typing import Callable
+from typing import cast
+from typing import Iterable
+from typing import Iterator
+from typing import List
+from typing import Mapping
+from typing import NoReturn
+from typing import Optional
+from typing import overload
+from typing import Tuple
+from typing import Type
+from typing import TypeVar
+from typing import Union
+
+from .interfaces import BindTyping
+from .interfaces import ConnectionEventsTarget
+from .interfaces import DBAPICursor
+from .interfaces import ExceptionContext
+from .interfaces import ExecuteStyle
+from .interfaces import ExecutionContext
+from .interfaces import IsolationLevel
+from .util import _distill_params_20
+from .util import _distill_raw_params
+from .util import TransactionalContext
+from .. import exc
+from .. import inspection
+from .. import log
+from .. import util
+from ..sql import compiler
+from ..sql import util as sql_util
+
+if typing.TYPE_CHECKING:
+    from . import CursorResult
+    from . import ScalarResult
+    from .interfaces import _AnyExecuteParams
+    from .interfaces import _AnyMultiExecuteParams
+    from .interfaces import _CoreAnyExecuteParams
+    from .interfaces import _CoreMultiExecuteParams
+    from .interfaces import _CoreSingleExecuteParams
+    from .interfaces import _DBAPIAnyExecuteParams
+    from .interfaces import _DBAPISingleExecuteParams
+    from .interfaces import _ExecuteOptions
+    from .interfaces import CompiledCacheType
+    from .interfaces import CoreExecuteOptionsParameter
+    from .interfaces import Dialect
+    from .interfaces import SchemaTranslateMapType
+    from .reflection import Inspector  # noqa
+    from .url import URL
+    from ..event import dispatcher
+    from ..log import _EchoFlagType
+    from ..pool import _ConnectionFairy
+    from ..pool import Pool
+    from ..pool import PoolProxiedConnection
+    from ..sql import Executable
+    from ..sql._typing import _InfoType
+    from ..sql.compiler import Compiled
+    from ..sql.ddl import ExecutableDDLElement
+    from ..sql.ddl import SchemaDropper
+    from ..sql.ddl import SchemaGenerator
+    from ..sql.functions import FunctionElement
+    from ..sql.schema import DefaultGenerator
+    from ..sql.schema import HasSchemaAttr
+    from ..sql.schema import SchemaItem
+    from ..sql.selectable import TypedReturnsRows
+
+
+_T = TypeVar("_T", bound=Any)
+_EMPTY_EXECUTION_OPTS: _ExecuteOptions = util.EMPTY_DICT
+NO_OPTIONS: Mapping[str, Any] = util.EMPTY_DICT
+
+
+class Connection(ConnectionEventsTarget, inspection.Inspectable["Inspector"]):
+    """Provides high-level functionality for a wrapped DB-API connection.
+
+    The :class:`_engine.Connection` object is procured by calling the
+    :meth:`_engine.Engine.connect` method of the :class:`_engine.Engine`
+    object, and provides services for execution of SQL statements as well
+    as transaction control.
+
+    The Connection object is **not** thread-safe. While a Connection can be
+    shared among threads using properly synchronized access, it is still
+    possible that the underlying DBAPI connection may not support shared
+    access between threads. Check the DBAPI documentation for details.
+
+    The Connection object represents a single DBAPI connection checked out
+    from the connection pool. In this state, the connection pool has no
+    affect upon the connection, including its expiration or timeout state.
+    For the connection pool to properly manage connections, connections
+    should be returned to the connection pool (i.e. ``connection.close()``)
+    whenever the connection is not in use.
+
+    .. index::
+      single: thread safety; Connection
+
+    """
+
+    dialect: Dialect
+    dispatch: dispatcher[ConnectionEventsTarget]
+
+    _sqla_logger_namespace = "sqlalchemy.engine.Connection"
+
+    # used by sqlalchemy.engine.util.TransactionalContext
+    _trans_context_manager: Optional[TransactionalContext] = None
+
+    # legacy as of 2.0, should be eventually deprecated and
+    # removed.  was used in the "pre_ping" recipe that's been in the docs
+    # a long time
+    should_close_with_result = False
+
+    _dbapi_connection: Optional[PoolProxiedConnection]
+
+    _execution_options: _ExecuteOptions
+
+    _transaction: Optional[RootTransaction]
+    _nested_transaction: Optional[NestedTransaction]
+
+    def __init__(
+        self,
+        engine: Engine,
+        connection: Optional[PoolProxiedConnection] = None,
+        _has_events: Optional[bool] = None,
+        _allow_revalidate: bool = True,
+        _allow_autobegin: bool = True,
+    ):
+        """Construct a new Connection."""
+        self.engine = engine
+        self.dialect = dialect = engine.dialect
+
+        if connection is None:
+            try:
+                self._dbapi_connection = engine.raw_connection()
+            except dialect.loaded_dbapi.Error as err:
+                Connection._handle_dbapi_exception_noconnection(
+                    err, dialect, engine
+                )
+                raise
+        else:
+            self._dbapi_connection = connection
+
+        self._transaction = self._nested_transaction = None
+        self.__savepoint_seq = 0
+        self.__in_begin = False
+
+        self.__can_reconnect = _allow_revalidate
+        self._allow_autobegin = _allow_autobegin
+        self._echo = self.engine._should_log_info()
+
+        if _has_events is None:
+            # if _has_events is sent explicitly as False,
+            # then don't join the dispatch of the engine; we don't
+            # want to handle any of the engine's events in that case.
+            self.dispatch = self.dispatch._join(engine.dispatch)
+        self._has_events = _has_events or (
+            _has_events is None and engine._has_events
+        )
+
+        self._execution_options = engine._execution_options
+
+        if self._has_events or self.engine._has_events:
+            self.dispatch.engine_connect(self)
+
+    # this can be assigned differently via
+    # characteristics.LoggingTokenCharacteristic
+    _message_formatter: Any = None
+
+    def _log_info(self, message: str, *arg: Any, **kw: Any) -> None:
+        fmt = self._message_formatter
+
+        if fmt:
+            message = fmt(message)
+
+        if log.STACKLEVEL:
+            kw["stacklevel"] = 1 + log.STACKLEVEL_OFFSET
+
+        self.engine.logger.info(message, *arg, **kw)
+
+    def _log_debug(self, message: str, *arg: Any, **kw: Any) -> None:
+        fmt = self._message_formatter
+
+        if fmt:
+            message = fmt(message)
+
+        if log.STACKLEVEL:
+            kw["stacklevel"] = 1 + log.STACKLEVEL_OFFSET
+
+        self.engine.logger.debug(message, *arg, **kw)
+
+    @property
+    def _schema_translate_map(self) -> Optional[SchemaTranslateMapType]:
+        schema_translate_map: Optional[SchemaTranslateMapType] = (
+            self._execution_options.get("schema_translate_map", None)
+        )
+
+        return schema_translate_map
+
+    def schema_for_object(self, obj: HasSchemaAttr) -> Optional[str]:
+        """Return the schema name for the given schema item taking into
+        account current schema translate map.
+
+        """
+
+        name = obj.schema
+        schema_translate_map: Optional[SchemaTranslateMapType] = (
+            self._execution_options.get("schema_translate_map", None)
+        )
+
+        if (
+            schema_translate_map
+            and name in schema_translate_map
+            and obj._use_schema_map
+        ):
+            return schema_translate_map[name]
+        else:
+            return name
+
+    def __enter__(self) -> Connection:
+        return self
+
+    def __exit__(self, type_: Any, value: Any, traceback: Any) -> None:
+        self.close()
+
+    @overload
+    def execution_options(
+        self,
+        *,
+        compiled_cache: Optional[CompiledCacheType] = ...,
+        logging_token: str = ...,
+        isolation_level: IsolationLevel = ...,
+        no_parameters: bool = False,
+        stream_results: bool = False,
+        max_row_buffer: int = ...,
+        yield_per: int = ...,
+        insertmanyvalues_page_size: int = ...,
+        schema_translate_map: Optional[SchemaTranslateMapType] = ...,
+        preserve_rowcount: bool = False,
+        **opt: Any,
+    ) -> Connection: ...
+
+    @overload
+    def execution_options(self, **opt: Any) -> Connection: ...
+
+    def execution_options(self, **opt: Any) -> Connection:
+        r"""Set non-SQL options for the connection which take effect
+        during execution.
+
+        This method modifies this :class:`_engine.Connection` **in-place**;
+        the return value is the same :class:`_engine.Connection` object
+        upon which the method is called.   Note that this is in contrast
+        to the behavior of the ``execution_options`` methods on other
+        objects such as :meth:`_engine.Engine.execution_options` and
+        :meth:`_sql.Executable.execution_options`.  The rationale is that many
+        such execution options necessarily modify the state of the base
+        DBAPI connection in any case so there is no feasible means of
+        keeping the effect of such an option localized to a "sub" connection.
+
+        .. versionchanged:: 2.0  The :meth:`_engine.Connection.execution_options`
+           method, in contrast to other objects with this method, modifies
+           the connection in-place without creating copy of it.
+
+        As discussed elsewhere, the :meth:`_engine.Connection.execution_options`
+        method accepts any arbitrary parameters including user defined names.
+        All parameters given are consumable in a number of ways including
+        by using the :meth:`_engine.Connection.get_execution_options` method.
+        See the examples at :meth:`_sql.Executable.execution_options`
+        and :meth:`_engine.Engine.execution_options`.
+
+        The keywords that are currently recognized by SQLAlchemy itself
+        include all those listed under :meth:`.Executable.execution_options`,
+        as well as others that are specific to :class:`_engine.Connection`.
+
+        :param compiled_cache: Available on: :class:`_engine.Connection`,
+          :class:`_engine.Engine`.
+
+          A dictionary where :class:`.Compiled` objects
+          will be cached when the :class:`_engine.Connection`
+          compiles a clause
+          expression into a :class:`.Compiled` object.  This dictionary will
+          supersede the statement cache that may be configured on the
+          :class:`_engine.Engine` itself.   If set to None, caching
+          is disabled, even if the engine has a configured cache size.
+
+          Note that the ORM makes use of its own "compiled" caches for
+          some operations, including flush operations.  The caching
+          used by the ORM internally supersedes a cache dictionary
+          specified here.
+
+        :param logging_token: Available on: :class:`_engine.Connection`,
+          :class:`_engine.Engine`, :class:`_sql.Executable`.
+
+          Adds the specified string token surrounded by brackets in log
+          messages logged by the connection, i.e. the logging that's enabled
+          either via the :paramref:`_sa.create_engine.echo` flag or via the
+          ``logging.getLogger("sqlalchemy.engine")`` logger. This allows a
+          per-connection or per-sub-engine token to be available which is
+          useful for debugging concurrent connection scenarios.
+
+          .. versionadded:: 1.4.0b2
+
+          .. seealso::
+
+            :ref:`dbengine_logging_tokens` - usage example
+
+            :paramref:`_sa.create_engine.logging_name` - adds a name to the
+            name used by the Python logger object itself.
+
+        :param isolation_level: Available on: :class:`_engine.Connection`,
+          :class:`_engine.Engine`.
+
+          Set the transaction isolation level for the lifespan of this
+          :class:`_engine.Connection` object.
+          Valid values include those string
+          values accepted by the :paramref:`_sa.create_engine.isolation_level`
+          parameter passed to :func:`_sa.create_engine`.  These levels are
+          semi-database specific; see individual dialect documentation for
+          valid levels.
+
+          The isolation level option applies the isolation level by emitting
+          statements on the DBAPI connection, and **necessarily affects the
+          original Connection object overall**. The isolation level will remain
+          at the given setting until explicitly changed, or when the DBAPI
+          connection itself is :term:`released` to the connection pool, i.e. the
+          :meth:`_engine.Connection.close` method is called, at which time an
+          event handler will emit additional statements on the DBAPI connection
+          in order to revert the isolation level change.
+
+          .. note:: The ``isolation_level`` execution option may only be
+             established before the :meth:`_engine.Connection.begin` method is
+             called, as well as before any SQL statements are emitted which
+             would otherwise trigger "autobegin", or directly after a call to
+             :meth:`_engine.Connection.commit` or
+             :meth:`_engine.Connection.rollback`. A database cannot change the
+             isolation level on a transaction in progress.
+
+          .. note:: The ``isolation_level`` execution option is implicitly
+             reset if the :class:`_engine.Connection` is invalidated, e.g. via
+             the :meth:`_engine.Connection.invalidate` method, or if a
+             disconnection error occurs. The new connection produced after the
+             invalidation will **not** have the selected isolation level
+             re-applied to it automatically.
+
+          .. seealso::
+
+                :ref:`dbapi_autocommit`
+
+                :meth:`_engine.Connection.get_isolation_level`
+                - view current actual level
+
+        :param no_parameters: Available on: :class:`_engine.Connection`,
+          :class:`_sql.Executable`.
+
+          When ``True``, if the final parameter
+          list or dictionary is totally empty, will invoke the
+          statement on the cursor as ``cursor.execute(statement)``,
+          not passing the parameter collection at all.
+          Some DBAPIs such as psycopg2 and mysql-python consider
+          percent signs as significant only when parameters are
+          present; this option allows code to generate SQL
+          containing percent signs (and possibly other characters)
+          that is neutral regarding whether it's executed by the DBAPI
+          or piped into a script that's later invoked by
+          command line tools.
+
+        :param stream_results: Available on: :class:`_engine.Connection`,
+          :class:`_sql.Executable`.
+
+          Indicate to the dialect that results should be "streamed" and not
+          pre-buffered, if possible.  For backends such as PostgreSQL, MySQL
+          and MariaDB, this indicates the use of a "server side cursor" as
+          opposed to a client side cursor.  Other backends such as that of
+          Oracle Database may already use server side cursors by default.
+
+          The usage of
+          :paramref:`_engine.Connection.execution_options.stream_results` is
+          usually combined with setting a fixed number of rows to to be fetched
+          in batches, to allow for efficient iteration of database rows while
+          at the same time not loading all result rows into memory at once;
+          this can be configured on a :class:`_engine.Result` object using the
+          :meth:`_engine.Result.yield_per` method, after execution has
+          returned a new :class:`_engine.Result`.   If
+          :meth:`_engine.Result.yield_per` is not used,
+          the :paramref:`_engine.Connection.execution_options.stream_results`
+          mode of operation will instead use a dynamically sized buffer
+          which buffers sets of rows at a time, growing on each batch
+          based on a fixed growth size up until a limit which may
+          be configured using the
+          :paramref:`_engine.Connection.execution_options.max_row_buffer`
+          parameter.
+
+          When using the ORM to fetch ORM mapped objects from a result,
+          :meth:`_engine.Result.yield_per` should always be used with
+          :paramref:`_engine.Connection.execution_options.stream_results`,
+          so that the ORM does not fetch all rows into new ORM objects at once.
+
+          For typical use, the
+          :paramref:`_engine.Connection.execution_options.yield_per` execution
+          option should be preferred, which sets up both
+          :paramref:`_engine.Connection.execution_options.stream_results` and
+          :meth:`_engine.Result.yield_per` at once. This option is supported
+          both at a core level by :class:`_engine.Connection` as well as by the
+          ORM :class:`_engine.Session`; the latter is described at
+          :ref:`orm_queryguide_yield_per`.
+
+          .. seealso::
+
+            :ref:`engine_stream_results` - background on
+            :paramref:`_engine.Connection.execution_options.stream_results`
+
+            :paramref:`_engine.Connection.execution_options.max_row_buffer`
+
+            :paramref:`_engine.Connection.execution_options.yield_per`
+
+            :ref:`orm_queryguide_yield_per` - in the :ref:`queryguide_toplevel`
+            describing the ORM version of ``yield_per``
+
+        :param max_row_buffer: Available on: :class:`_engine.Connection`,
+          :class:`_sql.Executable`.  Sets a maximum
+          buffer size to use when the
+          :paramref:`_engine.Connection.execution_options.stream_results`
+          execution option is used on a backend that supports server side
+          cursors.  The default value if not specified is 1000.
+
+          .. seealso::
+
+            :paramref:`_engine.Connection.execution_options.stream_results`
+
+            :ref:`engine_stream_results`
+
+
+        :param yield_per: Available on: :class:`_engine.Connection`,
+          :class:`_sql.Executable`.  Integer value applied which will
+          set the :paramref:`_engine.Connection.execution_options.stream_results`
+          execution option and invoke :meth:`_engine.Result.yield_per`
+          automatically at once.  Allows equivalent functionality as
+          is present when using this parameter with the ORM.
+
+          .. versionadded:: 1.4.40
+
+          .. seealso::
+
+            :ref:`engine_stream_results` - background and examples
+            on using server side cursors with Core.
+
+            :ref:`orm_queryguide_yield_per` - in the :ref:`queryguide_toplevel`
+            describing the ORM version of ``yield_per``
+
+        :param insertmanyvalues_page_size: Available on: :class:`_engine.Connection`,
+            :class:`_engine.Engine`. Number of rows to format into an
+            INSERT statement when the statement uses "insertmanyvalues" mode,
+            which is a paged form of bulk insert that is used for many backends
+            when using :term:`executemany` execution typically in conjunction
+            with RETURNING. Defaults to 1000. May also be modified on a
+            per-engine basis using the
+            :paramref:`_sa.create_engine.insertmanyvalues_page_size` parameter.
+
+            .. versionadded:: 2.0
+
+            .. seealso::
+
+                :ref:`engine_insertmanyvalues`
+
+        :param schema_translate_map: Available on: :class:`_engine.Connection`,
+          :class:`_engine.Engine`, :class:`_sql.Executable`.
+
+          A dictionary mapping schema names to schema names, that will be
+          applied to the :paramref:`_schema.Table.schema` element of each
+          :class:`_schema.Table`
+          encountered when SQL or DDL expression elements
+          are compiled into strings; the resulting schema name will be
+          converted based on presence in the map of the original name.
+
+          .. seealso::
+
+            :ref:`schema_translating`
+
+        :param preserve_rowcount: Boolean; when True, the ``cursor.rowcount``
+          attribute will be unconditionally memoized within the result and
+          made available via the :attr:`.CursorResult.rowcount` attribute.
+          Normally, this attribute is only preserved for UPDATE and DELETE
+          statements.  Using this option, the DBAPIs rowcount value can
+          be accessed for other kinds of statements such as INSERT and SELECT,
+          to the degree that the DBAPI supports these statements.  See
+          :attr:`.CursorResult.rowcount` for notes regarding the behavior
+          of this attribute.
+
+          .. versionadded:: 2.0.28
+
+        .. seealso::
+
+            :meth:`_engine.Engine.execution_options`
+
+            :meth:`.Executable.execution_options`
+
+            :meth:`_engine.Connection.get_execution_options`
+
+            :ref:`orm_queryguide_execution_options` - documentation on all
+            ORM-specific execution options
+
+        """  # noqa
+        if self._has_events or self.engine._has_events:
+            self.dispatch.set_connection_execution_options(self, opt)
+        self._execution_options = self._execution_options.union(opt)
+        self.dialect.set_connection_execution_options(self, opt)
+        return self
+
+    def get_execution_options(self) -> _ExecuteOptions:
+        """Get the non-SQL options which will take effect during execution.
+
+        .. versionadded:: 1.3
+
+        .. seealso::
+
+            :meth:`_engine.Connection.execution_options`
+        """
+        return self._execution_options
+
+    @property
+    def _still_open_and_dbapi_connection_is_valid(self) -> bool:
+        pool_proxied_connection = self._dbapi_connection
+        return (
+            pool_proxied_connection is not None
+            and pool_proxied_connection.is_valid
+        )
+
+    @property
+    def closed(self) -> bool:
+        """Return True if this connection is closed."""
+
+        return self._dbapi_connection is None and not self.__can_reconnect
+
+    @property
+    def invalidated(self) -> bool:
+        """Return True if this connection was invalidated.
+
+        This does not indicate whether or not the connection was
+        invalidated at the pool level, however
+
+        """
+
+        # prior to 1.4, "invalid" was stored as a state independent of
+        # "closed", meaning an invalidated connection could be "closed",
+        # the _dbapi_connection would be None and closed=True, yet the
+        # "invalid" flag would stay True.  This meant that there were
+        # three separate states (open/valid, closed/valid, closed/invalid)
+        # when there is really no reason for that; a connection that's
+        # "closed" does not need to be "invalid".  So the state is now
+        # represented by the two facts alone.
+
+        pool_proxied_connection = self._dbapi_connection
+        return pool_proxied_connection is None and self.__can_reconnect
+
+    @property
+    def connection(self) -> PoolProxiedConnection:
+        """The underlying DB-API connection managed by this Connection.
+
+        This is a SQLAlchemy connection-pool proxied connection
+        which then has the attribute
+        :attr:`_pool._ConnectionFairy.dbapi_connection` that refers to the
+        actual driver connection.
+
+        .. seealso::
+
+
+            :ref:`dbapi_connections`
+
+        """
+
+        if self._dbapi_connection is None:
+            try:
+                return self._revalidate_connection()
+            except (exc.PendingRollbackError, exc.ResourceClosedError):
+                raise
+            except BaseException as e:
+                self._handle_dbapi_exception(e, None, None, None, None)
+        else:
+            return self._dbapi_connection
+
+    def get_isolation_level(self) -> IsolationLevel:
+        """Return the current **actual** isolation level that's present on
+        the database within the scope of this connection.
+
+        This attribute will perform a live SQL operation against the database
+        in order to procure the current isolation level, so the value returned
+        is the actual level on the underlying DBAPI connection regardless of
+        how this state was set. This will be one of the four actual isolation
+        modes ``READ UNCOMMITTED``, ``READ COMMITTED``, ``REPEATABLE READ``,
+        ``SERIALIZABLE``. It will **not** include the ``AUTOCOMMIT`` isolation
+        level setting. Third party dialects may also feature additional
+        isolation level settings.
+
+        .. note::  This method **will not report** on the ``AUTOCOMMIT``
+          isolation level, which is a separate :term:`dbapi` setting that's
+          independent of **actual** isolation level.  When ``AUTOCOMMIT`` is
+          in use, the database connection still has a "traditional" isolation
+          mode in effect, that is typically one of the four values
+          ``READ UNCOMMITTED``, ``READ COMMITTED``, ``REPEATABLE READ``,
+          ``SERIALIZABLE``.
+
+        Compare to the :attr:`_engine.Connection.default_isolation_level`
+        accessor which returns the isolation level that is present on the
+        database at initial connection time.
+
+        .. seealso::
+
+            :attr:`_engine.Connection.default_isolation_level`
+            - view default level
+
+            :paramref:`_sa.create_engine.isolation_level`
+            - set per :class:`_engine.Engine` isolation level
+
+            :paramref:`.Connection.execution_options.isolation_level`
+            - set per :class:`_engine.Connection` isolation level
+
+        """
+        dbapi_connection = self.connection.dbapi_connection
+        assert dbapi_connection is not None
+        try:
+            return self.dialect.get_isolation_level(dbapi_connection)
+        except BaseException as e:
+            self._handle_dbapi_exception(e, None, None, None, None)
+
+    @property
+    def default_isolation_level(self) -> Optional[IsolationLevel]:
+        """The initial-connection time isolation level associated with the
+        :class:`_engine.Dialect` in use.
+
+        This value is independent of the
+        :paramref:`.Connection.execution_options.isolation_level` and
+        :paramref:`.Engine.execution_options.isolation_level` execution
+        options, and is determined by the :class:`_engine.Dialect` when the
+        first connection is created, by performing a SQL query against the
+        database for the current isolation level before any additional commands
+        have been emitted.
+
+        Calling this accessor does not invoke any new SQL queries.
+
+        .. seealso::
+
+            :meth:`_engine.Connection.get_isolation_level`
+            - view current actual isolation level
+
+            :paramref:`_sa.create_engine.isolation_level`
+            - set per :class:`_engine.Engine` isolation level
+
+            :paramref:`.Connection.execution_options.isolation_level`
+            - set per :class:`_engine.Connection` isolation level
+
+        """
+        return self.dialect.default_isolation_level
+
+    def _invalid_transaction(self) -> NoReturn:
+        raise exc.PendingRollbackError(
+            "Can't reconnect until invalid %stransaction is rolled "
+            "back.  Please rollback() fully before proceeding"
+            % ("savepoint " if self._nested_transaction is not None else ""),
+            code="8s2b",
+        )
+
+    def _revalidate_connection(self) -> PoolProxiedConnection:
+        if self.__can_reconnect and self.invalidated:
+            if self._transaction is not None:
+                self._invalid_transaction()
+            self._dbapi_connection = self.engine.raw_connection()
+            return self._dbapi_connection
+        raise exc.ResourceClosedError("This Connection is closed")
+
+    @property
+    def info(self) -> _InfoType:
+        """Info dictionary associated with the underlying DBAPI connection
+        referred to by this :class:`_engine.Connection`, allowing user-defined
+        data to be associated with the connection.
+
+        The data here will follow along with the DBAPI connection including
+        after it is returned to the connection pool and used again
+        in subsequent instances of :class:`_engine.Connection`.
+
+        """
+
+        return self.connection.info
+
+    def invalidate(self, exception: Optional[BaseException] = None) -> None:
+        """Invalidate the underlying DBAPI connection associated with
+        this :class:`_engine.Connection`.
+
+        An attempt will be made to close the underlying DBAPI connection
+        immediately; however if this operation fails, the error is logged
+        but not raised.  The connection is then discarded whether or not
+        close() succeeded.
+
+        Upon the next use (where "use" typically means using the
+        :meth:`_engine.Connection.execute` method or similar),
+        this :class:`_engine.Connection` will attempt to
+        procure a new DBAPI connection using the services of the
+        :class:`_pool.Pool` as a source of connectivity (e.g.
+        a "reconnection").
+
+        If a transaction was in progress (e.g. the
+        :meth:`_engine.Connection.begin` method has been called) when
+        :meth:`_engine.Connection.invalidate` method is called, at the DBAPI
+        level all state associated with this transaction is lost, as
+        the DBAPI connection is closed.  The :class:`_engine.Connection`
+        will not allow a reconnection to proceed until the
+        :class:`.Transaction` object is ended, by calling the
+        :meth:`.Transaction.rollback` method; until that point, any attempt at
+        continuing to use the :class:`_engine.Connection` will raise an
+        :class:`~sqlalchemy.exc.InvalidRequestError`.
+        This is to prevent applications from accidentally
+        continuing an ongoing transactional operations despite the
+        fact that the transaction has been lost due to an
+        invalidation.
+
+        The :meth:`_engine.Connection.invalidate` method,
+        just like auto-invalidation,
+        will at the connection pool level invoke the
+        :meth:`_events.PoolEvents.invalidate` event.
+
+        :param exception: an optional ``Exception`` instance that's the
+         reason for the invalidation.  is passed along to event handlers
+         and logging functions.
+
+        .. seealso::
+
+            :ref:`pool_connection_invalidation`
+
+        """
+
+        if self.invalidated:
+            return
+
+        if self.closed:
+            raise exc.ResourceClosedError("This Connection is closed")
+
+        if self._still_open_and_dbapi_connection_is_valid:
+            pool_proxied_connection = self._dbapi_connection
+            assert pool_proxied_connection is not None
+            pool_proxied_connection.invalidate(exception)
+
+        self._dbapi_connection = None
+
+    def detach(self) -> None:
+        """Detach the underlying DB-API connection from its connection pool.
+
+        E.g.::
+
+            with engine.connect() as conn:
+                conn.detach()
+                conn.execute(text("SET search_path TO schema1, schema2"))
+
+                # work with connection
+
+            # connection is fully closed (since we used "with:", can
+            # also call .close())
+
+        This :class:`_engine.Connection` instance will remain usable.
+        When closed
+        (or exited from a context manager context as above),
+        the DB-API connection will be literally closed and not
+        returned to its originating pool.
+
+        This method can be used to insulate the rest of an application
+        from a modified state on a connection (such as a transaction
+        isolation level or similar).
+
+        """
+
+        if self.closed:
+            raise exc.ResourceClosedError("This Connection is closed")
+
+        pool_proxied_connection = self._dbapi_connection
+        if pool_proxied_connection is None:
+            raise exc.InvalidRequestError(
+                "Can't detach an invalidated Connection"
+            )
+        pool_proxied_connection.detach()
+
+    def _autobegin(self) -> None:
+        if self._allow_autobegin and not self.__in_begin:
+            self.begin()
+
+    def begin(self) -> RootTransaction:
+        """Begin a transaction prior to autobegin occurring.
+
+        E.g.::
+
+            with engine.connect() as conn:
+                with conn.begin() as trans:
+                    conn.execute(table.insert(), {"username": "sandy"})
+
+        The returned object is an instance of :class:`_engine.RootTransaction`.
+        This object represents the "scope" of the transaction,
+        which completes when either the :meth:`_engine.Transaction.rollback`
+        or :meth:`_engine.Transaction.commit` method is called; the object
+        also works as a context manager as illustrated above.
+
+        The :meth:`_engine.Connection.begin` method begins a
+        transaction that normally will be begun in any case when the connection
+        is first used to execute a statement.  The reason this method might be
+        used would be to invoke the :meth:`_events.ConnectionEvents.begin`
+        event at a specific time, or to organize code within the scope of a
+        connection checkout in terms of context managed blocks, such as::
+
+            with engine.connect() as conn:
+                with conn.begin():
+                    conn.execute(...)
+                    conn.execute(...)
+
+                with conn.begin():
+                    conn.execute(...)
+                    conn.execute(...)
+
+        The above code is not  fundamentally any different in its behavior than
+        the following code  which does not use
+        :meth:`_engine.Connection.begin`; the below style is known
+        as "commit as you go" style::
+
+            with engine.connect() as conn:
+                conn.execute(...)
+                conn.execute(...)
+                conn.commit()
+
+                conn.execute(...)
+                conn.execute(...)
+                conn.commit()
+
+        From a database point of view, the :meth:`_engine.Connection.begin`
+        method does not emit any SQL or change the state of the underlying
+        DBAPI connection in any way; the Python DBAPI does not have any
+        concept of explicit transaction begin.
+
+        .. seealso::
+
+            :ref:`tutorial_working_with_transactions` - in the
+            :ref:`unified_tutorial`
+
+            :meth:`_engine.Connection.begin_nested` - use a SAVEPOINT
+
+            :meth:`_engine.Connection.begin_twophase` -
+            use a two phase /XID transaction
+
+            :meth:`_engine.Engine.begin` - context manager available from
+            :class:`_engine.Engine`
+
+        """
+        if self._transaction is None:
+            self._transaction = RootTransaction(self)
+            return self._transaction
+        else:
+            raise exc.InvalidRequestError(
+                "This connection has already initialized a SQLAlchemy "
+                "Transaction() object via begin() or autobegin; can't "
+                "call begin() here unless rollback() or commit() "
+                "is called first."
+            )
+
+    def begin_nested(self) -> NestedTransaction:
+        """Begin a nested transaction (i.e. SAVEPOINT) and return a transaction
+        handle that controls the scope of the SAVEPOINT.
+
+        E.g.::
+
+            with engine.begin() as connection:
+                with connection.begin_nested():
+                    connection.execute(table.insert(), {"username": "sandy"})
+
+        The returned object is an instance of
+        :class:`_engine.NestedTransaction`, which includes transactional
+        methods :meth:`_engine.NestedTransaction.commit` and
+        :meth:`_engine.NestedTransaction.rollback`; for a nested transaction,
+        these methods correspond to the operations "RELEASE SAVEPOINT <name>"
+        and "ROLLBACK TO SAVEPOINT <name>". The name of the savepoint is local
+        to the :class:`_engine.NestedTransaction` object and is generated
+        automatically. Like any other :class:`_engine.Transaction`, the
+        :class:`_engine.NestedTransaction` may be used as a context manager as
+        illustrated above which will "release" or "rollback" corresponding to
+        if the operation within the block were successful or raised an
+        exception.
+
+        Nested transactions require SAVEPOINT support in the underlying
+        database, else the behavior is undefined. SAVEPOINT is commonly used to
+        run operations within a transaction that may fail, while continuing the
+        outer transaction. E.g.::
+
+            from sqlalchemy import exc
+
+            with engine.begin() as connection:
+                trans = connection.begin_nested()
+                try:
+                    connection.execute(table.insert(), {"username": "sandy"})
+                    trans.commit()
+                except exc.IntegrityError:  # catch for duplicate username
+                    trans.rollback()  # rollback to savepoint
+
+                # outer transaction continues
+                connection.execute(...)
+
+        If :meth:`_engine.Connection.begin_nested` is called without first
+        calling :meth:`_engine.Connection.begin` or
+        :meth:`_engine.Engine.begin`, the :class:`_engine.Connection` object
+        will "autobegin" the outer transaction first. This outer transaction
+        may be committed using "commit-as-you-go" style, e.g.::
+
+            with engine.connect() as connection:  # begin() wasn't called
+
+                with connection.begin_nested():  # will auto-"begin()" first
+                    connection.execute(...)
+                # savepoint is released
+
+                connection.execute(...)
+
+                # explicitly commit outer transaction
+                connection.commit()
+
+                # can continue working with connection here
+
+        .. versionchanged:: 2.0
+
+            :meth:`_engine.Connection.begin_nested` will now participate
+            in the connection "autobegin" behavior that is new as of
+            2.0 / "future" style connections in 1.4.
+
+        .. seealso::
+
+            :meth:`_engine.Connection.begin`
+
+            :ref:`session_begin_nested` - ORM support for SAVEPOINT
+
+        """
+        if self._transaction is None:
+            self._autobegin()
+
+        return NestedTransaction(self)
+
+    def begin_twophase(self, xid: Optional[Any] = None) -> TwoPhaseTransaction:
+        """Begin a two-phase or XA transaction and return a transaction
+        handle.
+
+        The returned object is an instance of :class:`.TwoPhaseTransaction`,
+        which in addition to the methods provided by
+        :class:`.Transaction`, also provides a
+        :meth:`~.TwoPhaseTransaction.prepare` method.
+
+        :param xid: the two phase transaction id.  If not supplied, a
+          random id will be generated.
+
+        .. seealso::
+
+            :meth:`_engine.Connection.begin`
+
+            :meth:`_engine.Connection.begin_twophase`
+
+        """
+
+        if self._transaction is not None:
+            raise exc.InvalidRequestError(
+                "Cannot start a two phase transaction when a transaction "
+                "is already in progress."
+            )
+        if xid is None:
+            xid = self.engine.dialect.create_xid()
+        return TwoPhaseTransaction(self, xid)
+
+    def commit(self) -> None:
+        """Commit the transaction that is currently in progress.
+
+        This method commits the current transaction if one has been started.
+        If no transaction was started, the method has no effect, assuming
+        the connection is in a non-invalidated state.
+
+        A transaction is begun on a :class:`_engine.Connection` automatically
+        whenever a statement is first executed, or when the
+        :meth:`_engine.Connection.begin` method is called.
+
+        .. note:: The :meth:`_engine.Connection.commit` method only acts upon
+          the primary database transaction that is linked to the
+          :class:`_engine.Connection` object.  It does not operate upon a
+          SAVEPOINT that would have been invoked from the
+          :meth:`_engine.Connection.begin_nested` method; for control of a
+          SAVEPOINT, call :meth:`_engine.NestedTransaction.commit` on the
+          :class:`_engine.NestedTransaction` that is returned by the
+          :meth:`_engine.Connection.begin_nested` method itself.
+
+
+        """
+        if self._transaction:
+            self._transaction.commit()
+
+    def rollback(self) -> None:
+        """Roll back the transaction that is currently in progress.
+
+        This method rolls back the current transaction if one has been started.
+        If no transaction was started, the method has no effect.  If a
+        transaction was started and the connection is in an invalidated state,
+        the transaction is cleared using this method.
+
+        A transaction is begun on a :class:`_engine.Connection` automatically
+        whenever a statement is first executed, or when the
+        :meth:`_engine.Connection.begin` method is called.
+
+        .. note:: The :meth:`_engine.Connection.rollback` method only acts
+          upon the primary database transaction that is linked to the
+          :class:`_engine.Connection` object.  It does not operate upon a
+          SAVEPOINT that would have been invoked from the
+          :meth:`_engine.Connection.begin_nested` method; for control of a
+          SAVEPOINT, call :meth:`_engine.NestedTransaction.rollback` on the
+          :class:`_engine.NestedTransaction` that is returned by the
+          :meth:`_engine.Connection.begin_nested` method itself.
+
+
+        """
+        if self._transaction:
+            self._transaction.rollback()
+
+    def recover_twophase(self) -> List[Any]:
+        return self.engine.dialect.do_recover_twophase(self)
+
+    def rollback_prepared(self, xid: Any, recover: bool = False) -> None:
+        self.engine.dialect.do_rollback_twophase(self, xid, recover=recover)
+
+    def commit_prepared(self, xid: Any, recover: bool = False) -> None:
+        self.engine.dialect.do_commit_twophase(self, xid, recover=recover)
+
+    def in_transaction(self) -> bool:
+        """Return True if a transaction is in progress."""
+        return self._transaction is not None and self._transaction.is_active
+
+    def in_nested_transaction(self) -> bool:
+        """Return True if a transaction is in progress."""
+        return (
+            self._nested_transaction is not None
+            and self._nested_transaction.is_active
+        )
+
+    def _is_autocommit_isolation(self) -> bool:
+        opt_iso = self._execution_options.get("isolation_level", None)
+        return bool(
+            opt_iso == "AUTOCOMMIT"
+            or (
+                opt_iso is None
+                and self.engine.dialect._on_connect_isolation_level
+                == "AUTOCOMMIT"
+            )
+        )
+
+    def _get_required_transaction(self) -> RootTransaction:
+        trans = self._transaction
+        if trans is None:
+            raise exc.InvalidRequestError("connection is not in a transaction")
+        return trans
+
+    def _get_required_nested_transaction(self) -> NestedTransaction:
+        trans = self._nested_transaction
+        if trans is None:
+            raise exc.InvalidRequestError(
+                "connection is not in a nested transaction"
+            )
+        return trans
+
+    def get_transaction(self) -> Optional[RootTransaction]:
+        """Return the current root transaction in progress, if any.
+
+        .. versionadded:: 1.4
+
+        """
+
+        return self._transaction
+
+    def get_nested_transaction(self) -> Optional[NestedTransaction]:
+        """Return the current nested transaction in progress, if any.
+
+        .. versionadded:: 1.4
+
+        """
+        return self._nested_transaction
+
+    def _begin_impl(self, transaction: RootTransaction) -> None:
+        if self._echo:
+            if self._is_autocommit_isolation():
+                self._log_info(
+                    "BEGIN (implicit; DBAPI should not BEGIN due to "
+                    "autocommit mode)"
+                )
+            else:
+                self._log_info("BEGIN (implicit)")
+
+        self.__in_begin = True
+
+        if self._has_events or self.engine._has_events:
+            self.dispatch.begin(self)
+
+        try:
+            self.engine.dialect.do_begin(self.connection)
+        except BaseException as e:
+            self._handle_dbapi_exception(e, None, None, None, None)
+        finally:
+            self.__in_begin = False
+
+    def _rollback_impl(self) -> None:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.rollback(self)
+
+        if self._still_open_and_dbapi_connection_is_valid:
+            if self._echo:
+                if self._is_autocommit_isolation():
+                    self._log_info(
+                        "ROLLBACK using DBAPI connection.rollback(), "
+                        "DBAPI should ignore due to autocommit mode"
+                    )
+                else:
+                    self._log_info("ROLLBACK")
+            try:
+                self.engine.dialect.do_rollback(self.connection)
+            except BaseException as e:
+                self._handle_dbapi_exception(e, None, None, None, None)
+
+    def _commit_impl(self) -> None:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.commit(self)
+
+        if self._echo:
+            if self._is_autocommit_isolation():
+                self._log_info(
+                    "COMMIT using DBAPI connection.commit(), "
+                    "DBAPI should ignore due to autocommit mode"
+                )
+            else:
+                self._log_info("COMMIT")
+        try:
+            self.engine.dialect.do_commit(self.connection)
+        except BaseException as e:
+            self._handle_dbapi_exception(e, None, None, None, None)
+
+    def _savepoint_impl(self, name: Optional[str] = None) -> str:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.savepoint(self, name)
+
+        if name is None:
+            self.__savepoint_seq += 1
+            name = "sa_savepoint_%s" % self.__savepoint_seq
+        self.engine.dialect.do_savepoint(self, name)
+        return name
+
+    def _rollback_to_savepoint_impl(self, name: str) -> None:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.rollback_savepoint(self, name, None)
+
+        if self._still_open_and_dbapi_connection_is_valid:
+            self.engine.dialect.do_rollback_to_savepoint(self, name)
+
+    def _release_savepoint_impl(self, name: str) -> None:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.release_savepoint(self, name, None)
+
+        self.engine.dialect.do_release_savepoint(self, name)
+
+    def _begin_twophase_impl(self, transaction: TwoPhaseTransaction) -> None:
+        if self._echo:
+            self._log_info("BEGIN TWOPHASE (implicit)")
+        if self._has_events or self.engine._has_events:
+            self.dispatch.begin_twophase(self, transaction.xid)
+
+        self.__in_begin = True
+        try:
+            self.engine.dialect.do_begin_twophase(self, transaction.xid)
+        except BaseException as e:
+            self._handle_dbapi_exception(e, None, None, None, None)
+        finally:
+            self.__in_begin = False
+
+    def _prepare_twophase_impl(self, xid: Any) -> None:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.prepare_twophase(self, xid)
+
+        assert isinstance(self._transaction, TwoPhaseTransaction)
+        try:
+            self.engine.dialect.do_prepare_twophase(self, xid)
+        except BaseException as e:
+            self._handle_dbapi_exception(e, None, None, None, None)
+
+    def _rollback_twophase_impl(self, xid: Any, is_prepared: bool) -> None:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.rollback_twophase(self, xid, is_prepared)
+
+        if self._still_open_and_dbapi_connection_is_valid:
+            assert isinstance(self._transaction, TwoPhaseTransaction)
+            try:
+                self.engine.dialect.do_rollback_twophase(
+                    self, xid, is_prepared
+                )
+            except BaseException as e:
+                self._handle_dbapi_exception(e, None, None, None, None)
+
+    def _commit_twophase_impl(self, xid: Any, is_prepared: bool) -> None:
+        if self._has_events or self.engine._has_events:
+            self.dispatch.commit_twophase(self, xid, is_prepared)
+
+        assert isinstance(self._transaction, TwoPhaseTransaction)
+        try:
+            self.engine.dialect.do_commit_twophase(self, xid, is_prepared)
+        except BaseException as e:
+            self._handle_dbapi_exception(e, None, None, None, None)
+
+    def close(self) -> None:
+        """Close this :class:`_engine.Connection`.
+
+        This results in a release of the underlying database
+        resources, that is, the DBAPI connection referenced
+        internally. The DBAPI connection is typically restored
+        back to the connection-holding :class:`_pool.Pool` referenced
+        by the :class:`_engine.Engine` that produced this
+        :class:`_engine.Connection`. Any transactional state present on
+        the DBAPI connection is also unconditionally released via
+        the DBAPI connection's ``rollback()`` method, regardless
+        of any :class:`.Transaction` object that may be
+        outstanding with regards to this :class:`_engine.Connection`.
+
+        This has the effect of also calling :meth:`_engine.Connection.rollback`
+        if any transaction is in place.
+
+        After :meth:`_engine.Connection.close` is called, the
+        :class:`_engine.Connection` is permanently in a closed state,
+        and will allow no further operations.
+
+        """
+
+        if self._transaction:
+            self._transaction.close()
+            skip_reset = True
+        else:
+            skip_reset = False
+
+        if self._dbapi_connection is not None:
+            conn = self._dbapi_connection
+
+            # as we just closed the transaction, close the connection
+            # pool connection without doing an additional reset
+            if skip_reset:
+                cast("_ConnectionFairy", conn)._close_special(
+                    transaction_reset=True
+                )
+            else:
+                conn.close()
+
+            # There is a slight chance that conn.close() may have
+            # triggered an invalidation here in which case
+            # _dbapi_connection would already be None, however usually
+            # it will be non-None here and in a "closed" state.
+            self._dbapi_connection = None
+        self.__can_reconnect = False
+
+    @overload
+    def scalar(
+        self,
+        statement: TypedReturnsRows[Tuple[_T]],
+        parameters: Optional[_CoreSingleExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> Optional[_T]: ...
+
+    @overload
+    def scalar(
+        self,
+        statement: Executable,
+        parameters: Optional[_CoreSingleExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> Any: ...
+
+    def scalar(
+        self,
+        statement: Executable,
+        parameters: Optional[_CoreSingleExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> Any:
+        r"""Executes a SQL statement construct and returns a scalar object.
+
+        This method is shorthand for invoking the
+        :meth:`_engine.Result.scalar` method after invoking the
+        :meth:`_engine.Connection.execute` method.  Parameters are equivalent.
+
+        :return: a scalar Python value representing the first column of the
+         first row returned.
+
+        """
+        distilled_parameters = _distill_params_20(parameters)
+        try:
+            meth = statement._execute_on_scalar
+        except AttributeError as err:
+            raise exc.ObjectNotExecutableError(statement) from err
+        else:
+            return meth(
+                self,
+                distilled_parameters,
+                execution_options or NO_OPTIONS,
+            )
+
+    @overload
+    def scalars(
+        self,
+        statement: TypedReturnsRows[Tuple[_T]],
+        parameters: Optional[_CoreAnyExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> ScalarResult[_T]: ...
+
+    @overload
+    def scalars(
+        self,
+        statement: Executable,
+        parameters: Optional[_CoreAnyExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> ScalarResult[Any]: ...
+
+    def scalars(
+        self,
+        statement: Executable,
+        parameters: Optional[_CoreAnyExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> ScalarResult[Any]:
+        """Executes and returns a scalar result set, which yields scalar values
+        from the first column of each row.
+
+        This method is equivalent to calling :meth:`_engine.Connection.execute`
+        to receive a :class:`_result.Result` object, then invoking the
+        :meth:`_result.Result.scalars` method to produce a
+        :class:`_result.ScalarResult` instance.
+
+        :return: a :class:`_result.ScalarResult`
+
+        .. versionadded:: 1.4.24
+
+        """
+
+        return self.execute(
+            statement, parameters, execution_options=execution_options
+        ).scalars()
+
+    @overload
+    def execute(
+        self,
+        statement: TypedReturnsRows[_T],
+        parameters: Optional[_CoreAnyExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> CursorResult[_T]: ...
+
+    @overload
+    def execute(
+        self,
+        statement: Executable,
+        parameters: Optional[_CoreAnyExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> CursorResult[Any]: ...
+
+    def execute(
+        self,
+        statement: Executable,
+        parameters: Optional[_CoreAnyExecuteParams] = None,
+        *,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> CursorResult[Any]:
+        r"""Executes a SQL statement construct and returns a
+        :class:`_engine.CursorResult`.
+
+        :param statement: The statement to be executed.  This is always
+         an object that is in both the :class:`_expression.ClauseElement` and
+         :class:`_expression.Executable` hierarchies, including:
+
+         * :class:`_expression.Select`
+         * :class:`_expression.Insert`, :class:`_expression.Update`,
+           :class:`_expression.Delete`
+         * :class:`_expression.TextClause` and
+           :class:`_expression.TextualSelect`
+         * :class:`_schema.DDL` and objects which inherit from
+           :class:`_schema.ExecutableDDLElement`
+
+        :param parameters: parameters which will be bound into the statement.
+         This may be either a dictionary of parameter names to values,
+         or a mutable sequence (e.g. a list) of dictionaries.  When a
+         list of dictionaries is passed, the underlying statement execution
+         will make use of the DBAPI ``cursor.executemany()`` method.
+         When a single dictionary is passed, the DBAPI ``cursor.execute()``
+         method will be used.
+
+        :param execution_options: optional dictionary of execution options,
+         which will be associated with the statement execution.  This
+         dictionary can provide a subset of the options that are accepted
+         by :meth:`_engine.Connection.execution_options`.
+
+        :return: a :class:`_engine.Result` object.
+
+        """
+        distilled_parameters = _distill_params_20(parameters)
+        try:
+            meth = statement._execute_on_connection
+        except AttributeError as err:
+            raise exc.ObjectNotExecutableError(statement) from err
+        else:
+            return meth(
+                self,
+                distilled_parameters,
+                execution_options or NO_OPTIONS,
+            )
+
+    def _execute_function(
+        self,
+        func: FunctionElement[Any],
+        distilled_parameters: _CoreMultiExecuteParams,
+        execution_options: CoreExecuteOptionsParameter,
+    ) -> CursorResult[Any]:
+        """Execute a sql.FunctionElement object."""
+
+        return self._execute_clauseelement(
+            func.select(), distilled_parameters, execution_options
+        )
+
+    def _execute_default(
+        self,
+        default: DefaultGenerator,
+        distilled_parameters: _CoreMultiExecuteParams,
+        execution_options: CoreExecuteOptionsParameter,
+    ) -> Any:
+        """Execute a schema.ColumnDefault object."""
+
+        execution_options = self._execution_options.merge_with(
+            execution_options
+        )
+
+        event_multiparams: Optional[_CoreMultiExecuteParams]
+        event_params: Optional[_CoreAnyExecuteParams]
+
+        # note for event handlers, the "distilled parameters" which is always
+        # a list of dicts is broken out into separate "multiparams" and
+        # "params" collections, which allows the handler to distinguish
+        # between an executemany and execute style set of parameters.
+        if self._has_events or self.engine._has_events:
+            (
+                default,
+                distilled_parameters,
+                event_multiparams,
+                event_params,
+            ) = self._invoke_before_exec_event(
+                default, distilled_parameters, execution_options
+            )
+        else:
+            event_multiparams = event_params = None
+
+        try:
+            conn = self._dbapi_connection
+            if conn is None:
+                conn = self._revalidate_connection()
+
+            dialect = self.dialect
+            ctx = dialect.execution_ctx_cls._init_default(
+                dialect, self, conn, execution_options
+            )
+        except (exc.PendingRollbackError, exc.ResourceClosedError):
+            raise
+        except BaseException as e:
+            self._handle_dbapi_exception(e, None, None, None, None)
+
+        ret = ctx._exec_default(None, default, None)
+
+        if self._has_events or self.engine._has_events:
+            self.dispatch.after_execute(
+                self,
+                default,
+                event_multiparams,
+                event_params,
+                execution_options,
+                ret,
+            )
+
+        return ret
+
+    def _execute_ddl(
+        self,
+        ddl: ExecutableDDLElement,
+        distilled_parameters: _CoreMultiExecuteParams,
+        execution_options: CoreExecuteOptionsParameter,
+    ) -> CursorResult[Any]:
+        """Execute a schema.DDL object."""
+
+        exec_opts = ddl._execution_options.merge_with(
+            self._execution_options, execution_options
+        )
+
+        event_multiparams: Optional[_CoreMultiExecuteParams]
+        event_params: Optional[_CoreSingleExecuteParams]
+
+        if self._has_events or self.engine._has_events:
+            (
+                ddl,
+                distilled_parameters,
+                event_multiparams,
+                event_params,
+            ) = self._invoke_before_exec_event(
+                ddl, distilled_parameters, exec_opts
+            )
+        else:
+            event_multiparams = event_params = None
+
+        schema_translate_map = exec_opts.get("schema_translate_map", None)
+
+        dialect = self.dialect
+
+        compiled = ddl.compile(
+            dialect=dialect, schema_translate_map=schema_translate_map
+        )
+        ret = self._execute_context(
+            dialect,
+            dialect.execution_ctx_cls._init_ddl,
+            compiled,
+            None,
+            exec_opts,
+            compiled,
+        )
+        if self._has_events or self.engine._has_events:
+            self.dispatch.after_execute(
+                self,
+                ddl,
+                event_multiparams,
+                event_params,
+                exec_opts,
+                ret,
+            )
+        return ret
+
+    def _invoke_before_exec_event(
+        self,
+        elem: Any,
+        distilled_params: _CoreMultiExecuteParams,
+        execution_options: _ExecuteOptions,
+    ) -> Tuple[
+        Any,
+        _CoreMultiExecuteParams,
+        _CoreMultiExecuteParams,
+        _CoreSingleExecuteParams,
+    ]:
+        event_multiparams: _CoreMultiExecuteParams
+        event_params: _CoreSingleExecuteParams
+
+        if len(distilled_params) == 1:
+            event_multiparams, event_params = [], distilled_params[0]
+        else:
+            event_multiparams, event_params = distilled_params, {}
+
+        for fn in self.dispatch.before_execute:
+            elem, event_multiparams, event_params = fn(
+                self,
+                elem,
+                event_multiparams,
+                event_params,
+                execution_options,
+            )
+
+        if event_multiparams:
+            distilled_params = list(event_multiparams)
+            if event_params:
+                raise exc.InvalidRequestError(
+                    "Event handler can't return non-empty multiparams "
+                    "and params at the same time"
+                )
+        elif event_params:
+            distilled_params = [event_params]
+        else:
+            distilled_params = []
+
+        return elem, distilled_params, event_multiparams, event_params
+
+    def _execute_clauseelement(
+        self,
+        elem: Executable,
+        distilled_parameters: _CoreMultiExecuteParams,
+        execution_options: CoreExecuteOptionsParameter,
+    ) -> CursorResult[Any]:
+        """Execute a sql.ClauseElement object."""
+
+        execution_options = elem._execution_options.merge_with(
+            self._execution_options, execution_options
+        )
+
+        has_events = self._has_events or self.engine._has_events
+        if has_events:
+            (
+                elem,
+                distilled_parameters,
+                event_multiparams,
+                event_params,
+            ) = self._invoke_before_exec_event(
+                elem, distilled_parameters, execution_options
+            )
+
+        if distilled_parameters:
+            # ensure we don't retain a link to the view object for keys()
+            # which links to the values, which we don't want to cache
+            keys = sorted(distilled_parameters[0])
+            for_executemany = len(distilled_parameters) > 1
+        else:
+            keys = []
+            for_executemany = False
+
+        dialect = self.dialect
+
+        schema_translate_map = execution_options.get(
+            "schema_translate_map", None
+        )
+
+        compiled_cache: Optional[CompiledCacheType] = execution_options.get(
+            "compiled_cache", self.engine._compiled_cache
+        )
+
+        compiled_sql, extracted_params, cache_hit = elem._compile_w_cache(
+            dialect=dialect,
+            compiled_cache=compiled_cache,
+            column_keys=keys,
+            for_executemany=for_executemany,
+            schema_translate_map=schema_translate_map,
+            linting=self.dialect.compiler_linting | compiler.WARN_LINTING,
+        )
+        ret = self._execute_context(
+            dialect,
+            dialect.execution_ctx_cls._init_compiled,
+            compiled_sql,
+            distilled_parameters,
+            execution_options,
+            compiled_sql,
+            distilled_parameters,
+            elem,
+            extracted_params,
+            cache_hit=cache_hit,
+        )
+        if has_events:
+            self.dispatch.after_execute(
+                self,
+                elem,
+                event_multiparams,
+                event_params,
+                execution_options,
+                ret,
+            )
+        return ret
+
+    def _execute_compiled(
+        self,
+        compiled: Compiled,
+        distilled_parameters: _CoreMultiExecuteParams,
+        execution_options: CoreExecuteOptionsParameter = _EMPTY_EXECUTION_OPTS,
+    ) -> CursorResult[Any]:
+        """Execute a sql.Compiled object.
+
+        TODO: why do we have this?   likely deprecate or remove
+
+        """
+
+        execution_options = compiled.execution_options.merge_with(
+            self._execution_options, execution_options
+        )
+
+        if self._has_events or self.engine._has_events:
+            (
+                compiled,
+                distilled_parameters,
+                event_multiparams,
+                event_params,
+            ) = self._invoke_before_exec_event(
+                compiled, distilled_parameters, execution_options
+            )
+
+        dialect = self.dialect
+
+        ret = self._execute_context(
+            dialect,
+            dialect.execution_ctx_cls._init_compiled,
+            compiled,
+            distilled_parameters,
+            execution_options,
+            compiled,
+            distilled_parameters,
+            None,
+            None,
+        )
+        if self._has_events or self.engine._has_events:
+            self.dispatch.after_execute(
+                self,
+                compiled,
+                event_multiparams,
+                event_params,
+                execution_options,
+                ret,
+            )
+        return ret
+
+    def exec_driver_sql(
+        self,
+        statement: str,
+        parameters: Optional[_DBAPIAnyExecuteParams] = None,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> CursorResult[Any]:
+        r"""Executes a string SQL statement on the DBAPI cursor directly,
+        without any SQL compilation steps.
+
+        This can be used to pass any string directly to the
+        ``cursor.execute()`` method of the DBAPI in use.
+
+        :param statement: The statement str to be executed.   Bound parameters
+         must use the underlying DBAPI's paramstyle, such as "qmark",
+         "pyformat", "format", etc.
+
+        :param parameters: represent bound parameter values to be used in the
+         execution.  The format is one of:   a dictionary of named parameters,
+         a tuple of positional parameters, or a list containing either
+         dictionaries or tuples for multiple-execute support.
+
+        :return: a :class:`_engine.CursorResult`.
+
+         E.g. multiple dictionaries::
+
+
+             conn.exec_driver_sql(
+                 "INSERT INTO table (id, value) VALUES (%(id)s, %(value)s)",
+                 [{"id": 1, "value": "v1"}, {"id": 2, "value": "v2"}],
+             )
+
+         Single dictionary::
+
+             conn.exec_driver_sql(
+                 "INSERT INTO table (id, value) VALUES (%(id)s, %(value)s)",
+                 dict(id=1, value="v1"),
+             )
+
+         Single tuple::
+
+             conn.exec_driver_sql(
+                 "INSERT INTO table (id, value) VALUES (?, ?)", (1, "v1")
+             )
+
+         .. note:: The :meth:`_engine.Connection.exec_driver_sql` method does
+             not participate in the
+             :meth:`_events.ConnectionEvents.before_execute` and
+             :meth:`_events.ConnectionEvents.after_execute` events.   To
+             intercept calls to :meth:`_engine.Connection.exec_driver_sql`, use
+             :meth:`_events.ConnectionEvents.before_cursor_execute` and
+             :meth:`_events.ConnectionEvents.after_cursor_execute`.
+
+         .. seealso::
+
+            :pep:`249`
+
+        """
+
+        distilled_parameters = _distill_raw_params(parameters)
+
+        execution_options = self._execution_options.merge_with(
+            execution_options
+        )
+
+        dialect = self.dialect
+        ret = self._execute_context(
+            dialect,
+            dialect.execution_ctx_cls._init_statement,
+            statement,
+            None,
+            execution_options,
+            statement,
+            distilled_parameters,
+        )
+
+        return ret
+
+    def _execute_context(
+        self,
+        dialect: Dialect,
+        constructor: Callable[..., ExecutionContext],
+        statement: Union[str, Compiled],
+        parameters: Optional[_AnyMultiExecuteParams],
+        execution_options: _ExecuteOptions,
+        *args: Any,
+        **kw: Any,
+    ) -> CursorResult[Any]:
+        """Create an :class:`.ExecutionContext` and execute, returning
+        a :class:`_engine.CursorResult`."""
+
+        if execution_options:
+            yp = execution_options.get("yield_per", None)
+            if yp:
+                execution_options = execution_options.union(
+                    {"stream_results": True, "max_row_buffer": yp}
+                )
+        try:
+            conn = self._dbapi_connection
+            if conn is None:
+                conn = self._revalidate_connection()
+
+            context = constructor(
+                dialect, self, conn, execution_options, *args, **kw
+            )
+        except (exc.PendingRollbackError, exc.ResourceClosedError):
+            raise
+        except BaseException as e:
+            self._handle_dbapi_exception(
+                e, str(statement), parameters, None, None
+            )
+
+        if (
+            self._transaction
+            and not self._transaction.is_active
+            or (
+                self._nested_transaction
+                and not self._nested_transaction.is_active
+            )
+        ):
+            self._invalid_transaction()
+
+        elif self._trans_context_manager:
+            TransactionalContext._trans_ctx_check(self)
+
+        if self._transaction is None:
+            self._autobegin()
+
+        context.pre_exec()
+
+        if context.execute_style is ExecuteStyle.INSERTMANYVALUES:
+            return self._exec_insertmany_context(dialect, context)
+        else:
+            return self._exec_single_context(
+                dialect, context, statement, parameters
+            )
+
+    def _exec_single_context(
+        self,
+        dialect: Dialect,
+        context: ExecutionContext,
+        statement: Union[str, Compiled],
+        parameters: Optional[_AnyMultiExecuteParams],
+    ) -> CursorResult[Any]:
+        """continue the _execute_context() method for a single DBAPI
+        cursor.execute() or cursor.executemany() call.
+
+        """
+        if dialect.bind_typing is BindTyping.SETINPUTSIZES:
+            generic_setinputsizes = context._prepare_set_input_sizes()
+
+            if generic_setinputsizes:
+                try:
+                    dialect.do_set_input_sizes(
+                        context.cursor, generic_setinputsizes, context
+                    )
+                except BaseException as e:
+                    self._handle_dbapi_exception(
+                        e, str(statement), parameters, None, context
+                    )
+
+        cursor, str_statement, parameters = (
+            context.cursor,
+            context.statement,
+            context.parameters,
+        )
+
+        effective_parameters: Optional[_AnyExecuteParams]
+
+        if not context.executemany:
+            effective_parameters = parameters[0]
+        else:
+            effective_parameters = parameters
+
+        if self._has_events or self.engine._has_events:
+            for fn in self.dispatch.before_cursor_execute:
+                str_statement, effective_parameters = fn(
+                    self,
+                    cursor,
+                    str_statement,
+                    effective_parameters,
+                    context,
+                    context.executemany,
+                )
+
+        if self._echo:
+            self._log_info(str_statement)
+
+            stats = context._get_cache_stats()
+
+            if not self.engine.hide_parameters:
+                self._log_info(
+                    "[%s] %r",
+                    stats,
+                    sql_util._repr_params(
+                        effective_parameters,
+                        batches=10,
+                        ismulti=context.executemany,
+                    ),
+                )
+            else:
+                self._log_info(
+                    "[%s] [SQL parameters hidden due to hide_parameters=True]",
+                    stats,
+                )
+
+        evt_handled: bool = False
+        try:
+            if context.execute_style is ExecuteStyle.EXECUTEMANY:
+                effective_parameters = cast(
+                    "_CoreMultiExecuteParams", effective_parameters
+                )
+                if self.dialect._has_events:
+                    for fn in self.dialect.dispatch.do_executemany:
+                        if fn(
+                            cursor,
+                            str_statement,
+                            effective_parameters,
+                            context,
+                        ):
+                            evt_handled = True
+                            break
+                if not evt_handled:
+                    self.dialect.do_executemany(
+                        cursor,
+                        str_statement,
+                        effective_parameters,
+                        context,
+                    )
+            elif not effective_parameters and context.no_parameters:
+                if self.dialect._has_events:
+                    for fn in self.dialect.dispatch.do_execute_no_params:
+                        if fn(cursor, str_statement, context):
+                            evt_handled = True
+                            break
+                if not evt_handled:
+                    self.dialect.do_execute_no_params(
+                        cursor, str_statement, context
+                    )
+            else:
+                effective_parameters = cast(
+                    "_CoreSingleExecuteParams", effective_parameters
+                )
+                if self.dialect._has_events:
+                    for fn in self.dialect.dispatch.do_execute:
+                        if fn(
+                            cursor,
+                            str_statement,
+                            effective_parameters,
+                            context,
+                        ):
+                            evt_handled = True
+                            break
+                if not evt_handled:
+                    self.dialect.do_execute(
+                        cursor, str_statement, effective_parameters, context
+                    )
+
+            if self._has_events or self.engine._has_events:
+                self.dispatch.after_cursor_execute(
+                    self,
+                    cursor,
+                    str_statement,
+                    effective_parameters,
+                    context,
+                    context.executemany,
+                )
+
+            context.post_exec()
+
+            result = context._setup_result_proxy()
+
+        except BaseException as e:
+            self._handle_dbapi_exception(
+                e, str_statement, effective_parameters, cursor, context
+            )
+
+        return result
+
+    def _exec_insertmany_context(
+        self,
+        dialect: Dialect,
+        context: ExecutionContext,
+    ) -> CursorResult[Any]:
+        """continue the _execute_context() method for an "insertmanyvalues"
+        operation, which will invoke DBAPI
+        cursor.execute() one or more times with individual log and
+        event hook calls.
+
+        """
+
+        if dialect.bind_typing is BindTyping.SETINPUTSIZES:
+            generic_setinputsizes = context._prepare_set_input_sizes()
+        else:
+            generic_setinputsizes = None
+
+        cursor, str_statement, parameters = (
+            context.cursor,
+            context.statement,
+            context.parameters,
+        )
+
+        effective_parameters = parameters
+
+        engine_events = self._has_events or self.engine._has_events
+        if self.dialect._has_events:
+            do_execute_dispatch: Iterable[Any] = (
+                self.dialect.dispatch.do_execute
+            )
+        else:
+            do_execute_dispatch = ()
+
+        if self._echo:
+            stats = context._get_cache_stats() + " (insertmanyvalues)"
+
+        preserve_rowcount = context.execution_options.get(
+            "preserve_rowcount", False
+        )
+        rowcount = 0
+
+        for imv_batch in dialect._deliver_insertmanyvalues_batches(
+            self,
+            cursor,
+            str_statement,
+            effective_parameters,
+            generic_setinputsizes,
+            context,
+        ):
+            if imv_batch.processed_setinputsizes:
+                try:
+                    dialect.do_set_input_sizes(
+                        context.cursor,
+                        imv_batch.processed_setinputsizes,
+                        context,
+                    )
+                except BaseException as e:
+                    self._handle_dbapi_exception(
+                        e,
+                        sql_util._long_statement(imv_batch.replaced_statement),
+                        imv_batch.replaced_parameters,
+                        None,
+                        context,
+                        is_sub_exec=True,
+                    )
+
+            sub_stmt = imv_batch.replaced_statement
+            sub_params = imv_batch.replaced_parameters
+
+            if engine_events:
+                for fn in self.dispatch.before_cursor_execute:
+                    sub_stmt, sub_params = fn(
+                        self,
+                        cursor,
+                        sub_stmt,
+                        sub_params,
+                        context,
+                        True,
+                    )
+
+            if self._echo:
+                self._log_info(sql_util._long_statement(sub_stmt))
+
+                imv_stats = f""" {imv_batch.batchnum}/{
+                            imv_batch.total_batches
+                } ({
+                    'ordered'
+                    if imv_batch.rows_sorted else 'unordered'
+                }{
+                    '; batch not supported'
+                    if imv_batch.is_downgraded
+                    else ''
+                })"""
+
+                if imv_batch.batchnum == 1:
+                    stats += imv_stats
+                else:
+                    stats = f"insertmanyvalues{imv_stats}"
+
+                if not self.engine.hide_parameters:
+                    self._log_info(
+                        "[%s] %r",
+                        stats,
+                        sql_util._repr_params(
+                            sub_params,
+                            batches=10,
+                            ismulti=False,
+                        ),
+                    )
+                else:
+                    self._log_info(
+                        "[%s] [SQL parameters hidden due to "
+                        "hide_parameters=True]",
+                        stats,
+                    )
+
+            try:
+                for fn in do_execute_dispatch:
+                    if fn(
+                        cursor,
+                        sub_stmt,
+                        sub_params,
+                        context,
+                    ):
+                        break
+                else:
+                    dialect.do_execute(
+                        cursor,
+                        sub_stmt,
+                        sub_params,
+                        context,
+                    )
+
+            except BaseException as e:
+                self._handle_dbapi_exception(
+                    e,
+                    sql_util._long_statement(sub_stmt),
+                    sub_params,
+                    cursor,
+                    context,
+                    is_sub_exec=True,
+                )
+
+            if engine_events:
+                self.dispatch.after_cursor_execute(
+                    self,
+                    cursor,
+                    str_statement,
+                    effective_parameters,
+                    context,
+                    context.executemany,
+                )
+
+            if preserve_rowcount:
+                rowcount += imv_batch.current_batch_size
+
+        try:
+            context.post_exec()
+
+            if preserve_rowcount:
+                context._rowcount = rowcount  # type: ignore[attr-defined]
+
+            result = context._setup_result_proxy()
+
+        except BaseException as e:
+            self._handle_dbapi_exception(
+                e, str_statement, effective_parameters, cursor, context
+            )
+
+        return result
+
+    def _cursor_execute(
+        self,
+        cursor: DBAPICursor,
+        statement: str,
+        parameters: _DBAPISingleExecuteParams,
+        context: Optional[ExecutionContext] = None,
+    ) -> None:
+        """Execute a statement + params on the given cursor.
+
+        Adds appropriate logging and exception handling.
+
+        This method is used by DefaultDialect for special-case
+        executions, such as for sequences and column defaults.
+        The path of statement execution in the majority of cases
+        terminates at _execute_context().
+
+        """
+        if self._has_events or self.engine._has_events:
+            for fn in self.dispatch.before_cursor_execute:
+                statement, parameters = fn(
+                    self, cursor, statement, parameters, context, False
+                )
+
+        if self._echo:
+            self._log_info(statement)
+            self._log_info("[raw sql] %r", parameters)
+        try:
+            for fn in (
+                ()
+                if not self.dialect._has_events
+                else self.dialect.dispatch.do_execute
+            ):
+                if fn(cursor, statement, parameters, context):
+                    break
+            else:
+                self.dialect.do_execute(cursor, statement, parameters, context)
+        except BaseException as e:
+            self._handle_dbapi_exception(
+                e, statement, parameters, cursor, context
+            )
+
+        if self._has_events or self.engine._has_events:
+            self.dispatch.after_cursor_execute(
+                self, cursor, statement, parameters, context, False
+            )
+
+    def _safe_close_cursor(self, cursor: DBAPICursor) -> None:
+        """Close the given cursor, catching exceptions
+        and turning into log warnings.
+
+        """
+        try:
+            cursor.close()
+        except Exception:
+            # log the error through the connection pool's logger.
+            self.engine.pool.logger.error(
+                "Error closing cursor", exc_info=True
+            )
+
+    _reentrant_error = False
+    _is_disconnect = False
+
+    def _handle_dbapi_exception(
+        self,
+        e: BaseException,
+        statement: Optional[str],
+        parameters: Optional[_AnyExecuteParams],
+        cursor: Optional[DBAPICursor],
+        context: Optional[ExecutionContext],
+        is_sub_exec: bool = False,
+    ) -> NoReturn:
+        exc_info = sys.exc_info()
+
+        is_exit_exception = util.is_exit_exception(e)
+
+        if not self._is_disconnect:
+            self._is_disconnect = (
+                isinstance(e, self.dialect.loaded_dbapi.Error)
+                and not self.closed
+                and self.dialect.is_disconnect(
+                    e,
+                    self._dbapi_connection if not self.invalidated else None,
+                    cursor,
+                )
+            ) or (is_exit_exception and not self.closed)
+
+        invalidate_pool_on_disconnect = not is_exit_exception
+
+        ismulti: bool = (
+            not is_sub_exec and context.executemany
+            if context is not None
+            else False
+        )
+        if self._reentrant_error:
+            raise exc.DBAPIError.instance(
+                statement,
+                parameters,
+                e,
+                self.dialect.loaded_dbapi.Error,
+                hide_parameters=self.engine.hide_parameters,
+                dialect=self.dialect,
+                ismulti=ismulti,
+            ).with_traceback(exc_info[2]) from e
+        self._reentrant_error = True
+        try:
+            # non-DBAPI error - if we already got a context,
+            # or there's no string statement, don't wrap it
+            should_wrap = isinstance(e, self.dialect.loaded_dbapi.Error) or (
+                statement is not None
+                and context is None
+                and not is_exit_exception
+            )
+
+            if should_wrap:
+                sqlalchemy_exception = exc.DBAPIError.instance(
+                    statement,
+                    parameters,
+                    cast(Exception, e),
+                    self.dialect.loaded_dbapi.Error,
+                    hide_parameters=self.engine.hide_parameters,
+                    connection_invalidated=self._is_disconnect,
+                    dialect=self.dialect,
+                    ismulti=ismulti,
+                )
+            else:
+                sqlalchemy_exception = None
+
+            newraise = None
+
+            if (self.dialect._has_events) and not self._execution_options.get(
+                "skip_user_error_events", False
+            ):
+                ctx = ExceptionContextImpl(
+                    e,
+                    sqlalchemy_exception,
+                    self.engine,
+                    self.dialect,
+                    self,
+                    cursor,
+                    statement,
+                    parameters,
+                    context,
+                    self._is_disconnect,
+                    invalidate_pool_on_disconnect,
+                    False,
+                )
+
+                for fn in self.dialect.dispatch.handle_error:
+                    try:
+                        # handler returns an exception;
+                        # call next handler in a chain
+                        per_fn = fn(ctx)
+                        if per_fn is not None:
+                            ctx.chained_exception = newraise = per_fn
+                    except Exception as _raised:
+                        # handler raises an exception - stop processing
+                        newraise = _raised
+                        break
+
+                if self._is_disconnect != ctx.is_disconnect:
+                    self._is_disconnect = ctx.is_disconnect
+                    if sqlalchemy_exception:
+                        sqlalchemy_exception.connection_invalidated = (
+                            ctx.is_disconnect
+                        )
+
+                # set up potentially user-defined value for
+                # invalidate pool.
+                invalidate_pool_on_disconnect = (
+                    ctx.invalidate_pool_on_disconnect
+                )
+
+            if should_wrap and context:
+                context.handle_dbapi_exception(e)
+
+            if not self._is_disconnect:
+                if cursor:
+                    self._safe_close_cursor(cursor)
+                # "autorollback" was mostly relevant in 1.x series.
+                # It's very unlikely to reach here, as the connection
+                # does autobegin so when we are here, we are usually
+                # in an explicit / semi-explicit transaction.
+                # however we have a test which manufactures this
+                # scenario in any case using an event handler.
+                # test/engine/test_execute.py-> test_actual_autorollback
+                if not self.in_transaction():
+                    self._rollback_impl()
+
+            if newraise:
+                raise newraise.with_traceback(exc_info[2]) from e
+            elif should_wrap:
+                assert sqlalchemy_exception is not None
+                raise sqlalchemy_exception.with_traceback(exc_info[2]) from e
+            else:
+                assert exc_info[1] is not None
+                raise exc_info[1].with_traceback(exc_info[2])
+        finally:
+            del self._reentrant_error
+            if self._is_disconnect:
+                del self._is_disconnect
+                if not self.invalidated:
+                    dbapi_conn_wrapper = self._dbapi_connection
+                    assert dbapi_conn_wrapper is not None
+                    if invalidate_pool_on_disconnect:
+                        self.engine.pool._invalidate(dbapi_conn_wrapper, e)
+                    self.invalidate(e)
+
+    @classmethod
+    def _handle_dbapi_exception_noconnection(
+        cls,
+        e: BaseException,
+        dialect: Dialect,
+        engine: Optional[Engine] = None,
+        is_disconnect: Optional[bool] = None,
+        invalidate_pool_on_disconnect: bool = True,
+        is_pre_ping: bool = False,
+    ) -> NoReturn:
+        exc_info = sys.exc_info()
+
+        if is_disconnect is None:
+            is_disconnect = isinstance(
+                e, dialect.loaded_dbapi.Error
+            ) and dialect.is_disconnect(e, None, None)
+
+        should_wrap = isinstance(e, dialect.loaded_dbapi.Error)
+
+        if should_wrap:
+            sqlalchemy_exception = exc.DBAPIError.instance(
+                None,
+                None,
+                cast(Exception, e),
+                dialect.loaded_dbapi.Error,
+                hide_parameters=(
+                    engine.hide_parameters if engine is not None else False
+                ),
+                connection_invalidated=is_disconnect,
+                dialect=dialect,
+            )
+        else:
+            sqlalchemy_exception = None
+
+        newraise = None
+
+        if dialect._has_events:
+            ctx = ExceptionContextImpl(
+                e,
+                sqlalchemy_exception,
+                engine,
+                dialect,
+                None,
+                None,
+                None,
+                None,
+                None,
+                is_disconnect,
+                invalidate_pool_on_disconnect,
+                is_pre_ping,
+            )
+            for fn in dialect.dispatch.handle_error:
+                try:
+                    # handler returns an exception;
+                    # call next handler in a chain
+                    per_fn = fn(ctx)
+                    if per_fn is not None:
+                        ctx.chained_exception = newraise = per_fn
+                except Exception as _raised:
+                    # handler raises an exception - stop processing
+                    newraise = _raised
+                    break
+
+            if sqlalchemy_exception and is_disconnect != ctx.is_disconnect:
+                sqlalchemy_exception.connection_invalidated = is_disconnect = (
+                    ctx.is_disconnect
+                )
+
+        if newraise:
+            raise newraise.with_traceback(exc_info[2]) from e
+        elif should_wrap:
+            assert sqlalchemy_exception is not None
+            raise sqlalchemy_exception.with_traceback(exc_info[2]) from e
+        else:
+            assert exc_info[1] is not None
+            raise exc_info[1].with_traceback(exc_info[2])
+
+    def _run_ddl_visitor(
+        self,
+        visitorcallable: Type[Union[SchemaGenerator, SchemaDropper]],
+        element: SchemaItem,
+        **kwargs: Any,
+    ) -> None:
+        """run a DDL visitor.
+
+        This method is only here so that the MockConnection can change the
+        options given to the visitor so that "checkfirst" is skipped.
+
+        """
+        visitorcallable(self.dialect, self, **kwargs).traverse_single(element)
+
+
+class ExceptionContextImpl(ExceptionContext):
+    """Implement the :class:`.ExceptionContext` interface."""
+
+    __slots__ = (
+        "connection",
+        "engine",
+        "dialect",
+        "cursor",
+        "statement",
+        "parameters",
+        "original_exception",
+        "sqlalchemy_exception",
+        "chained_exception",
+        "execution_context",
+        "is_disconnect",
+        "invalidate_pool_on_disconnect",
+        "is_pre_ping",
+    )
+
+    def __init__(
+        self,
+        exception: BaseException,
+        sqlalchemy_exception: Optional[exc.StatementError],
+        engine: Optional[Engine],
+        dialect: Dialect,
+        connection: Optional[Connection],
+        cursor: Optional[DBAPICursor],
+        statement: Optional[str],
+        parameters: Optional[_DBAPIAnyExecuteParams],
+        context: Optional[ExecutionContext],
+        is_disconnect: bool,
+        invalidate_pool_on_disconnect: bool,
+        is_pre_ping: bool,
+    ):
+        self.engine = engine
+        self.dialect = dialect
+        self.connection = connection
+        self.sqlalchemy_exception = sqlalchemy_exception
+        self.original_exception = exception
+        self.execution_context = context
+        self.statement = statement
+        self.parameters = parameters
+        self.is_disconnect = is_disconnect
+        self.invalidate_pool_on_disconnect = invalidate_pool_on_disconnect
+        self.is_pre_ping = is_pre_ping
+
+
+class Transaction(TransactionalContext):
+    """Represent a database transaction in progress.
+
+    The :class:`.Transaction` object is procured by
+    calling the :meth:`_engine.Connection.begin` method of
+    :class:`_engine.Connection`::
+
+        from sqlalchemy import create_engine
+
+        engine = create_engine("postgresql+psycopg2://scott:tiger@localhost/test")
+        connection = engine.connect()
+        trans = connection.begin()
+        connection.execute(text("insert into x (a, b) values (1, 2)"))
+        trans.commit()
+
+    The object provides :meth:`.rollback` and :meth:`.commit`
+    methods in order to control transaction boundaries.  It
+    also implements a context manager interface so that
+    the Python ``with`` statement can be used with the
+    :meth:`_engine.Connection.begin` method::
+
+        with connection.begin():
+            connection.execute(text("insert into x (a, b) values (1, 2)"))
+
+    The Transaction object is **not** threadsafe.
+
+    .. seealso::
+
+        :meth:`_engine.Connection.begin`
+
+        :meth:`_engine.Connection.begin_twophase`
+
+        :meth:`_engine.Connection.begin_nested`
+
+    .. index::
+      single: thread safety; Transaction
+    """  # noqa
+
+    __slots__ = ()
+
+    _is_root: bool = False
+    is_active: bool
+    connection: Connection
+
+    def __init__(self, connection: Connection):
+        raise NotImplementedError()
+
+    @property
+    def _deactivated_from_connection(self) -> bool:
+        """True if this transaction is totally deactivated from the connection
+        and therefore can no longer affect its state.
+
+        """
+        raise NotImplementedError()
+
+    def _do_close(self) -> None:
+        raise NotImplementedError()
+
+    def _do_rollback(self) -> None:
+        raise NotImplementedError()
+
+    def _do_commit(self) -> None:
+        raise NotImplementedError()
+
+    @property
+    def is_valid(self) -> bool:
+        return self.is_active and not self.connection.invalidated
+
+    def close(self) -> None:
+        """Close this :class:`.Transaction`.
+
+        If this transaction is the base transaction in a begin/commit
+        nesting, the transaction will rollback().  Otherwise, the
+        method returns.
+
+        This is used to cancel a Transaction without affecting the scope of
+        an enclosing transaction.
+
+        """
+        try:
+            self._do_close()
+        finally:
+            assert not self.is_active
+
+    def rollback(self) -> None:
+        """Roll back this :class:`.Transaction`.
+
+        The implementation of this may vary based on the type of transaction in
+        use:
+
+        * For a simple database transaction (e.g. :class:`.RootTransaction`),
+          it corresponds to a ROLLBACK.
+
+        * For a :class:`.NestedTransaction`, it corresponds to a
+          "ROLLBACK TO SAVEPOINT" operation.
+
+        * For a :class:`.TwoPhaseTransaction`, DBAPI-specific methods for two
+          phase transactions may be used.
+
+
+        """
+        try:
+            self._do_rollback()
+        finally:
+            assert not self.is_active
+
+    def commit(self) -> None:
+        """Commit this :class:`.Transaction`.
+
+        The implementation of this may vary based on the type of transaction in
+        use:
+
+        * For a simple database transaction (e.g. :class:`.RootTransaction`),
+          it corresponds to a COMMIT.
+
+        * For a :class:`.NestedTransaction`, it corresponds to a
+          "RELEASE SAVEPOINT" operation.
+
+        * For a :class:`.TwoPhaseTransaction`, DBAPI-specific methods for two
+          phase transactions may be used.
+
+        """
+        try:
+            self._do_commit()
+        finally:
+            assert not self.is_active
+
+    def _get_subject(self) -> Connection:
+        return self.connection
+
+    def _transaction_is_active(self) -> bool:
+        return self.is_active
+
+    def _transaction_is_closed(self) -> bool:
+        return not self._deactivated_from_connection
+
+    def _rollback_can_be_called(self) -> bool:
+        # for RootTransaction / NestedTransaction, it's safe to call
+        # rollback() even if the transaction is deactive and no warnings
+        # will be emitted.  tested in
+        # test_transaction.py -> test_no_rollback_in_deactive(?:_savepoint)?
+        return True
+
+
+class RootTransaction(Transaction):
+    """Represent the "root" transaction on a :class:`_engine.Connection`.
+
+    This corresponds to the current "BEGIN/COMMIT/ROLLBACK" that's occurring
+    for the :class:`_engine.Connection`. The :class:`_engine.RootTransaction`
+    is created by calling upon the :meth:`_engine.Connection.begin` method, and
+    remains associated with the :class:`_engine.Connection` throughout its
+    active span. The current :class:`_engine.RootTransaction` in use is
+    accessible via the :attr:`_engine.Connection.get_transaction` method of
+    :class:`_engine.Connection`.
+
+    In :term:`2.0 style` use, the :class:`_engine.Connection` also employs
+    "autobegin" behavior that will create a new
+    :class:`_engine.RootTransaction` whenever a connection in a
+    non-transactional state is used to emit commands on the DBAPI connection.
+    The scope of the :class:`_engine.RootTransaction` in 2.0 style
+    use can be controlled using the :meth:`_engine.Connection.commit` and
+    :meth:`_engine.Connection.rollback` methods.
+
+
+    """
+
+    _is_root = True
+
+    __slots__ = ("connection", "is_active")
+
+    def __init__(self, connection: Connection):
+        assert connection._transaction is None
+        if connection._trans_context_manager:
+            TransactionalContext._trans_ctx_check(connection)
+        self.connection = connection
+        self._connection_begin_impl()
+        connection._transaction = self
+
+        self.is_active = True
+
+    def _deactivate_from_connection(self) -> None:
+        if self.is_active:
+            assert self.connection._transaction is self
+            self.is_active = False
+
+        elif self.connection._transaction is not self:
+            util.warn("transaction already deassociated from connection")
+
+    @property
+    def _deactivated_from_connection(self) -> bool:
+        return self.connection._transaction is not self
+
+    def _connection_begin_impl(self) -> None:
+        self.connection._begin_impl(self)
+
+    def _connection_rollback_impl(self) -> None:
+        self.connection._rollback_impl()
+
+    def _connection_commit_impl(self) -> None:
+        self.connection._commit_impl()
+
+    def _close_impl(self, try_deactivate: bool = False) -> None:
+        try:
+            if self.is_active:
+                self._connection_rollback_impl()
+
+            if self.connection._nested_transaction:
+                self.connection._nested_transaction._cancel()
+        finally:
+            if self.is_active or try_deactivate:
+                self._deactivate_from_connection()
+            if self.connection._transaction is self:
+                self.connection._transaction = None
+
+        assert not self.is_active
+        assert self.connection._transaction is not self
+
+    def _do_close(self) -> None:
+        self._close_impl()
+
+    def _do_rollback(self) -> None:
+        self._close_impl(try_deactivate=True)
+
+    def _do_commit(self) -> None:
+        if self.is_active:
+            assert self.connection._transaction is self
+
+            try:
+                self._connection_commit_impl()
+            finally:
+                # whether or not commit succeeds, cancel any
+                # nested transactions, make this transaction "inactive"
+                # and remove it as a reset agent
+                if self.connection._nested_transaction:
+                    self.connection._nested_transaction._cancel()
+
+                self._deactivate_from_connection()
+
+            # ...however only remove as the connection's current transaction
+            # if commit succeeded.  otherwise it stays on so that a rollback
+            # needs to occur.
+            self.connection._transaction = None
+        else:
+            if self.connection._transaction is self:
+                self.connection._invalid_transaction()
+            else:
+                raise exc.InvalidRequestError("This transaction is inactive")
+
+        assert not self.is_active
+        assert self.connection._transaction is not self
+
+
+class NestedTransaction(Transaction):
+    """Represent a 'nested', or SAVEPOINT transaction.
+
+    The :class:`.NestedTransaction` object is created by calling the
+    :meth:`_engine.Connection.begin_nested` method of
+    :class:`_engine.Connection`.
+
+    When using :class:`.NestedTransaction`, the semantics of "begin" /
+    "commit" / "rollback" are as follows:
+
+    * the "begin" operation corresponds to the "BEGIN SAVEPOINT" command, where
+      the savepoint is given an explicit name that is part of the state
+      of this object.
+
+    * The :meth:`.NestedTransaction.commit` method corresponds to a
+      "RELEASE SAVEPOINT" operation, using the savepoint identifier associated
+      with this :class:`.NestedTransaction`.
+
+    * The :meth:`.NestedTransaction.rollback` method corresponds to a
+      "ROLLBACK TO SAVEPOINT" operation, using the savepoint identifier
+      associated with this :class:`.NestedTransaction`.
+
+    The rationale for mimicking the semantics of an outer transaction in
+    terms of savepoints so that code may deal with a "savepoint" transaction
+    and an "outer" transaction in an agnostic way.
+
+    .. seealso::
+
+        :ref:`session_begin_nested` - ORM version of the SAVEPOINT API.
+
+    """
+
+    __slots__ = ("connection", "is_active", "_savepoint", "_previous_nested")
+
+    _savepoint: str
+
+    def __init__(self, connection: Connection):
+        assert connection._transaction is not None
+        if connection._trans_context_manager:
+            TransactionalContext._trans_ctx_check(connection)
+        self.connection = connection
+        self._savepoint = self.connection._savepoint_impl()
+        self.is_active = True
+        self._previous_nested = connection._nested_transaction
+        connection._nested_transaction = self
+
+    def _deactivate_from_connection(self, warn: bool = True) -> None:
+        if self.connection._nested_transaction is self:
+            self.connection._nested_transaction = self._previous_nested
+        elif warn:
+            util.warn(
+                "nested transaction already deassociated from connection"
+            )
+
+    @property
+    def _deactivated_from_connection(self) -> bool:
+        return self.connection._nested_transaction is not self
+
+    def _cancel(self) -> None:
+        # called by RootTransaction when the outer transaction is
+        # committed, rolled back, or closed to cancel all savepoints
+        # without any action being taken
+        self.is_active = False
+        self._deactivate_from_connection()
+        if self._previous_nested:
+            self._previous_nested._cancel()
+
+    def _close_impl(
+        self, deactivate_from_connection: bool, warn_already_deactive: bool
+    ) -> None:
+        try:
+            if (
+                self.is_active
+                and self.connection._transaction
+                and self.connection._transaction.is_active
+            ):
+                self.connection._rollback_to_savepoint_impl(self._savepoint)
+        finally:
+            self.is_active = False
+
+            if deactivate_from_connection:
+                self._deactivate_from_connection(warn=warn_already_deactive)
+
+        assert not self.is_active
+        if deactivate_from_connection:
+            assert self.connection._nested_transaction is not self
+
+    def _do_close(self) -> None:
+        self._close_impl(True, False)
+
+    def _do_rollback(self) -> None:
+        self._close_impl(True, True)
+
+    def _do_commit(self) -> None:
+        if self.is_active:
+            try:
+                self.connection._release_savepoint_impl(self._savepoint)
+            finally:
+                # nested trans becomes inactive on failed release
+                # unconditionally.  this prevents it from trying to
+                # emit SQL when it rolls back.
+                self.is_active = False
+
+            # but only de-associate from connection if it succeeded
+            self._deactivate_from_connection()
+        else:
+            if self.connection._nested_transaction is self:
+                self.connection._invalid_transaction()
+            else:
+                raise exc.InvalidRequestError(
+                    "This nested transaction is inactive"
+                )
+
+
+class TwoPhaseTransaction(RootTransaction):
+    """Represent a two-phase transaction.
+
+    A new :class:`.TwoPhaseTransaction` object may be procured
+    using the :meth:`_engine.Connection.begin_twophase` method.
+
+    The interface is the same as that of :class:`.Transaction`
+    with the addition of the :meth:`prepare` method.
+
+    """
+
+    __slots__ = ("xid", "_is_prepared")
+
+    xid: Any
+
+    def __init__(self, connection: Connection, xid: Any):
+        self._is_prepared = False
+        self.xid = xid
+        super().__init__(connection)
+
+    def prepare(self) -> None:
+        """Prepare this :class:`.TwoPhaseTransaction`.
+
+        After a PREPARE, the transaction can be committed.
+
+        """
+        if not self.is_active:
+            raise exc.InvalidRequestError("This transaction is inactive")
+        self.connection._prepare_twophase_impl(self.xid)
+        self._is_prepared = True
+
+    def _connection_begin_impl(self) -> None:
+        self.connection._begin_twophase_impl(self)
+
+    def _connection_rollback_impl(self) -> None:
+        self.connection._rollback_twophase_impl(self.xid, self._is_prepared)
+
+    def _connection_commit_impl(self) -> None:
+        self.connection._commit_twophase_impl(self.xid, self._is_prepared)
+
+
+class Engine(
+    ConnectionEventsTarget, log.Identified, inspection.Inspectable["Inspector"]
+):
+    """
+    Connects a :class:`~sqlalchemy.pool.Pool` and
+    :class:`~sqlalchemy.engine.interfaces.Dialect` together to provide a
+    source of database connectivity and behavior.
+
+    An :class:`_engine.Engine` object is instantiated publicly using the
+    :func:`~sqlalchemy.create_engine` function.
+
+    .. seealso::
+
+        :doc:`/core/engines`
+
+        :ref:`connections_toplevel`
+
+    """
+
+    dispatch: dispatcher[ConnectionEventsTarget]
+
+    _compiled_cache: Optional[CompiledCacheType]
+
+    _execution_options: _ExecuteOptions = _EMPTY_EXECUTION_OPTS
+    _has_events: bool = False
+    _connection_cls: Type[Connection] = Connection
+    _sqla_logger_namespace: str = "sqlalchemy.engine.Engine"
+    _is_future: bool = False
+
+    _schema_translate_map: Optional[SchemaTranslateMapType] = None
+    _option_cls: Type[OptionEngine]
+
+    dialect: Dialect
+    pool: Pool
+    url: URL
+    hide_parameters: bool
+
+    def __init__(
+        self,
+        pool: Pool,
+        dialect: Dialect,
+        url: URL,
+        logging_name: Optional[str] = None,
+        echo: Optional[_EchoFlagType] = None,
+        query_cache_size: int = 500,
+        execution_options: Optional[Mapping[str, Any]] = None,
+        hide_parameters: bool = False,
+    ):
+        self.pool = pool
+        self.url = url
+        self.dialect = dialect
+        if logging_name:
+            self.logging_name = logging_name
+        self.echo = echo
+        self.hide_parameters = hide_parameters
+        if query_cache_size != 0:
+            self._compiled_cache = util.LRUCache(
+                query_cache_size, size_alert=self._lru_size_alert
+            )
+        else:
+            self._compiled_cache = None
+        log.instance_logger(self, echoflag=echo)
+        if execution_options:
+            self.update_execution_options(**execution_options)
+
+    def _lru_size_alert(self, cache: util.LRUCache[Any, Any]) -> None:
+        if self._should_log_info():
+            self.logger.info(
+                "Compiled cache size pruning from %d items to %d.  "
+                "Increase cache size to reduce the frequency of pruning.",
+                len(cache),
+                cache.capacity,
+            )
+
+    @property
+    def engine(self) -> Engine:
+        """Returns this :class:`.Engine`.
+
+        Used for legacy schemes that accept :class:`.Connection` /
+        :class:`.Engine` objects within the same variable.
+
+        """
+        return self
+
+    def clear_compiled_cache(self) -> None:
+        """Clear the compiled cache associated with the dialect.
+
+        This applies **only** to the built-in cache that is established
+        via the :paramref:`_engine.create_engine.query_cache_size` parameter.
+        It will not impact any dictionary caches that were passed via the
+        :paramref:`.Connection.execution_options.compiled_cache` parameter.
+
+        .. versionadded:: 1.4
+
+        """
+        if self._compiled_cache:
+            self._compiled_cache.clear()
+
+    def update_execution_options(self, **opt: Any) -> None:
+        r"""Update the default execution_options dictionary
+        of this :class:`_engine.Engine`.
+
+        The given keys/values in \**opt are added to the
+        default execution options that will be used for
+        all connections.  The initial contents of this dictionary
+        can be sent via the ``execution_options`` parameter
+        to :func:`_sa.create_engine`.
+
+        .. seealso::
+
+            :meth:`_engine.Connection.execution_options`
+
+            :meth:`_engine.Engine.execution_options`
+
+        """
+        self.dispatch.set_engine_execution_options(self, opt)
+        self._execution_options = self._execution_options.union(opt)
+        self.dialect.set_engine_execution_options(self, opt)
+
+    @overload
+    def execution_options(
+        self,
+        *,
+        compiled_cache: Optional[CompiledCacheType] = ...,
+        logging_token: str = ...,
+        isolation_level: IsolationLevel = ...,
+        insertmanyvalues_page_size: int = ...,
+        schema_translate_map: Optional[SchemaTranslateMapType] = ...,
+        **opt: Any,
+    ) -> OptionEngine: ...
+
+    @overload
+    def execution_options(self, **opt: Any) -> OptionEngine: ...
+
+    def execution_options(self, **opt: Any) -> OptionEngine:
+        """Return a new :class:`_engine.Engine` that will provide
+        :class:`_engine.Connection` objects with the given execution options.
+
+        The returned :class:`_engine.Engine` remains related to the original
+        :class:`_engine.Engine` in that it shares the same connection pool and
+        other state:
+
+        * The :class:`_pool.Pool` used by the new :class:`_engine.Engine`
+          is the
+          same instance.  The :meth:`_engine.Engine.dispose`
+          method will replace
+          the connection pool instance for the parent engine as well
+          as this one.
+        * Event listeners are "cascaded" - meaning, the new
+          :class:`_engine.Engine`
+          inherits the events of the parent, and new events can be associated
+          with the new :class:`_engine.Engine` individually.
+        * The logging configuration and logging_name is copied from the parent
+          :class:`_engine.Engine`.
+
+        The intent of the :meth:`_engine.Engine.execution_options` method is
+        to implement schemes where multiple :class:`_engine.Engine`
+        objects refer to the same connection pool, but are differentiated
+        by options that affect some execution-level behavior for each
+        engine.    One such example is breaking into separate "reader" and
+        "writer" :class:`_engine.Engine` instances, where one
+        :class:`_engine.Engine`
+        has a lower :term:`isolation level` setting configured or is even
+        transaction-disabled using "autocommit".  An example of this
+        configuration is at :ref:`dbapi_autocommit_multiple`.
+
+        Another example is one that
+        uses a custom option ``shard_id`` which is consumed by an event
+        to change the current schema on a database connection::
+
+            from sqlalchemy import event
+            from sqlalchemy.engine import Engine
+
+            primary_engine = create_engine("mysql+mysqldb://")
+            shard1 = primary_engine.execution_options(shard_id="shard1")
+            shard2 = primary_engine.execution_options(shard_id="shard2")
+
+            shards = {"default": "base", "shard_1": "db1", "shard_2": "db2"}
+
+
+            @event.listens_for(Engine, "before_cursor_execute")
+            def _switch_shard(conn, cursor, stmt, params, context, executemany):
+                shard_id = conn.get_execution_options().get("shard_id", "default")
+                current_shard = conn.info.get("current_shard", None)
+
+                if current_shard != shard_id:
+                    cursor.execute("use %s" % shards[shard_id])
+                    conn.info["current_shard"] = shard_id
+
+        The above recipe illustrates two :class:`_engine.Engine` objects that
+        will each serve as factories for :class:`_engine.Connection` objects
+        that have pre-established "shard_id" execution options present. A
+        :meth:`_events.ConnectionEvents.before_cursor_execute` event handler
+        then interprets this execution option to emit a MySQL ``use`` statement
+        to switch databases before a statement execution, while at the same
+        time keeping track of which database we've established using the
+        :attr:`_engine.Connection.info` dictionary.
+
+        .. seealso::
+
+            :meth:`_engine.Connection.execution_options`
+            - update execution options
+            on a :class:`_engine.Connection` object.
+
+            :meth:`_engine.Engine.update_execution_options`
+            - update the execution
+            options for a given :class:`_engine.Engine` in place.
+
+            :meth:`_engine.Engine.get_execution_options`
+
+
+        """  # noqa: E501
+        return self._option_cls(self, opt)
+
+    def get_execution_options(self) -> _ExecuteOptions:
+        """Get the non-SQL options which will take effect during execution.
+
+        .. versionadded: 1.3
+
+        .. seealso::
+
+            :meth:`_engine.Engine.execution_options`
+        """
+        return self._execution_options
+
+    @property
+    def name(self) -> str:
+        """String name of the :class:`~sqlalchemy.engine.interfaces.Dialect`
+        in use by this :class:`Engine`.
+
+        """
+
+        return self.dialect.name
+
+    @property
+    def driver(self) -> str:
+        """Driver name of the :class:`~sqlalchemy.engine.interfaces.Dialect`
+        in use by this :class:`Engine`.
+
+        """
+
+        return self.dialect.driver
+
+    echo = log.echo_property()
+
+    def __repr__(self) -> str:
+        return "Engine(%r)" % (self.url,)
+
+    def dispose(self, close: bool = True) -> None:
+        """Dispose of the connection pool used by this
+        :class:`_engine.Engine`.
+
+        A new connection pool is created immediately after the old one has been
+        disposed. The previous connection pool is disposed either actively, by
+        closing out all currently checked-in connections in that pool, or
+        passively, by losing references to it but otherwise not closing any
+        connections. The latter strategy is more appropriate for an initializer
+        in a forked Python process.
+
+        :param close: if left at its default of ``True``, has the
+         effect of fully closing all **currently checked in**
+         database connections.  Connections that are still checked out
+         will **not** be closed, however they will no longer be associated
+         with this :class:`_engine.Engine`,
+         so when they are closed individually, eventually the
+         :class:`_pool.Pool` which they are associated with will
+         be garbage collected and they will be closed out fully, if
+         not already closed on checkin.
+
+         If set to ``False``, the previous connection pool is de-referenced,
+         and otherwise not touched in any way.
+
+        .. versionadded:: 1.4.33  Added the :paramref:`.Engine.dispose.close`
+            parameter to allow the replacement of a connection pool in a child
+            process without interfering with the connections used by the parent
+            process.
+
+
+        .. seealso::
+
+            :ref:`engine_disposal`
+
+            :ref:`pooling_multiprocessing`
+
+        """
+        if close:
+            self.pool.dispose()
+        self.pool = self.pool.recreate()
+        self.dispatch.engine_disposed(self)
+
+    @contextlib.contextmanager
+    def _optional_conn_ctx_manager(
+        self, connection: Optional[Connection] = None
+    ) -> Iterator[Connection]:
+        if connection is None:
+            with self.connect() as conn:
+                yield conn
+        else:
+            yield connection
+
+    @contextlib.contextmanager
+    def begin(self) -> Iterator[Connection]:
+        """Return a context manager delivering a :class:`_engine.Connection`
+        with a :class:`.Transaction` established.
+
+        E.g.::
+
+            with engine.begin() as conn:
+                conn.execute(text("insert into table (x, y, z) values (1, 2, 3)"))
+                conn.execute(text("my_special_procedure(5)"))
+
+        Upon successful operation, the :class:`.Transaction`
+        is committed.  If an error is raised, the :class:`.Transaction`
+        is rolled back.
+
+        .. seealso::
+
+            :meth:`_engine.Engine.connect` - procure a
+            :class:`_engine.Connection` from
+            an :class:`_engine.Engine`.
+
+            :meth:`_engine.Connection.begin` - start a :class:`.Transaction`
+            for a particular :class:`_engine.Connection`.
+
+        """  # noqa: E501
+        with self.connect() as conn:
+            with conn.begin():
+                yield conn
+
+    def _run_ddl_visitor(
+        self,
+        visitorcallable: Type[Union[SchemaGenerator, SchemaDropper]],
+        element: SchemaItem,
+        **kwargs: Any,
+    ) -> None:
+        with self.begin() as conn:
+            conn._run_ddl_visitor(visitorcallable, element, **kwargs)
+
+    def connect(self) -> Connection:
+        """Return a new :class:`_engine.Connection` object.
+
+        The :class:`_engine.Connection` acts as a Python context manager, so
+        the typical use of this method looks like::
+
+            with engine.connect() as connection:
+                connection.execute(text("insert into table values ('foo')"))
+                connection.commit()
+
+        Where above, after the block is completed, the connection is "closed"
+        and its underlying DBAPI resources are returned to the connection pool.
+        This also has the effect of rolling back any transaction that
+        was explicitly begun or was begun via autobegin, and will
+        emit the :meth:`_events.ConnectionEvents.rollback` event if one was
+        started and is still in progress.
+
+        .. seealso::
+
+            :meth:`_engine.Engine.begin`
+
+        """
+
+        return self._connection_cls(self)
+
+    def raw_connection(self) -> PoolProxiedConnection:
+        """Return a "raw" DBAPI connection from the connection pool.
+
+        The returned object is a proxied version of the DBAPI
+        connection object used by the underlying driver in use.
+        The object will have all the same behavior as the real DBAPI
+        connection, except that its ``close()`` method will result in the
+        connection being returned to the pool, rather than being closed
+        for real.
+
+        This method provides direct DBAPI connection access for
+        special situations when the API provided by
+        :class:`_engine.Connection`
+        is not needed.   When a :class:`_engine.Connection` object is already
+        present, the DBAPI connection is available using
+        the :attr:`_engine.Connection.connection` accessor.
+
+        .. seealso::
+
+            :ref:`dbapi_connections`
+
+        """
+        return self.pool.connect()
+
+
+class OptionEngineMixin(log.Identified):
+    _sa_propagate_class_events = False
+
+    dispatch: dispatcher[ConnectionEventsTarget]
+    _compiled_cache: Optional[CompiledCacheType]
+    dialect: Dialect
+    pool: Pool
+    url: URL
+    hide_parameters: bool
+    echo: log.echo_property
+
+    def __init__(
+        self, proxied: Engine, execution_options: CoreExecuteOptionsParameter
+    ):
+        self._proxied = proxied
+        self.url = proxied.url
+        self.dialect = proxied.dialect
+        self.logging_name = proxied.logging_name
+        self.echo = proxied.echo
+        self._compiled_cache = proxied._compiled_cache
+        self.hide_parameters = proxied.hide_parameters
+        log.instance_logger(self, echoflag=self.echo)
+
+        # note: this will propagate events that are assigned to the parent
+        # engine after this OptionEngine is created.   Since we share
+        # the events of the parent we also disallow class-level events
+        # to apply to the OptionEngine class directly.
+        #
+        # the other way this can work would be to transfer existing
+        # events only, using:
+        # self.dispatch._update(proxied.dispatch)
+        #
+        # that might be more appropriate however it would be a behavioral
+        # change for logic that assigns events to the parent engine and
+        # would like it to take effect for the already-created sub-engine.
+        self.dispatch = self.dispatch._join(proxied.dispatch)
+
+        self._execution_options = proxied._execution_options
+        self.update_execution_options(**execution_options)
+
+    def update_execution_options(self, **opt: Any) -> None:
+        raise NotImplementedError()
+
+    if not typing.TYPE_CHECKING:
+        # https://github.com/python/typing/discussions/1095
+
+        @property
+        def pool(self) -> Pool:
+            return self._proxied.pool
+
+        @pool.setter
+        def pool(self, pool: Pool) -> None:
+            self._proxied.pool = pool
+
+        @property
+        def _has_events(self) -> bool:
+            return self._proxied._has_events or self.__dict__.get(
+                "_has_events", False
+            )
+
+        @_has_events.setter
+        def _has_events(self, value: bool) -> None:
+            self.__dict__["_has_events"] = value
+
+
+class OptionEngine(OptionEngineMixin, Engine):
+    def update_execution_options(self, **opt: Any) -> None:
+        Engine.update_execution_options(self, **opt)
+
+
+Engine._option_cls = OptionEngine