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authorcyfraeviolae <cyfraeviolae>2024-04-03 03:10:44 -0400
committercyfraeviolae <cyfraeviolae>2024-04-03 03:10:44 -0400
commit6d7ba58f880be618ade07f8ea080fe8c4bf8a896 (patch)
treeb1c931051ffcebd2bd9d61d98d6233ffa289bbce /venv/lib/python3.11/site-packages/sqlalchemy/orm/scoping.py
parent4f884c9abc32990b4061a1bb6997b4b37e58ea0b (diff)
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+# orm/scoping.py
+# Copyright (C) 2005-2024 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
+
+from __future__ import annotations
+
+from typing import Any
+from typing import Callable
+from typing import Dict
+from typing import Generic
+from typing import Iterable
+from typing import Iterator
+from typing import Optional
+from typing import overload
+from typing import Sequence
+from typing import Tuple
+from typing import Type
+from typing import TYPE_CHECKING
+from typing import TypeVar
+from typing import Union
+
+from .session import _S
+from .session import Session
+from .. import exc as sa_exc
+from .. import util
+from ..util import create_proxy_methods
+from ..util import ScopedRegistry
+from ..util import ThreadLocalRegistry
+from ..util import warn
+from ..util import warn_deprecated
+from ..util.typing import Protocol
+
+if TYPE_CHECKING:
+ from ._typing import _EntityType
+ from ._typing import _IdentityKeyType
+ from ._typing import OrmExecuteOptionsParameter
+ from .identity import IdentityMap
+ from .interfaces import ORMOption
+ from .mapper import Mapper
+ from .query import Query
+ from .query import RowReturningQuery
+ from .session import _BindArguments
+ from .session import _EntityBindKey
+ from .session import _PKIdentityArgument
+ from .session import _SessionBind
+ from .session import sessionmaker
+ from .session import SessionTransaction
+ from ..engine import Connection
+ from ..engine import CursorResult
+ from ..engine import Engine
+ from ..engine import Result
+ from ..engine import Row
+ from ..engine import RowMapping
+ from ..engine.interfaces import _CoreAnyExecuteParams
+ from ..engine.interfaces import _CoreSingleExecuteParams
+ from ..engine.interfaces import CoreExecuteOptionsParameter
+ from ..engine.result import ScalarResult
+ from ..sql._typing import _ColumnsClauseArgument
+ from ..sql._typing import _T0
+ from ..sql._typing import _T1
+ from ..sql._typing import _T2
+ from ..sql._typing import _T3
+ from ..sql._typing import _T4
+ from ..sql._typing import _T5
+ from ..sql._typing import _T6
+ from ..sql._typing import _T7
+ from ..sql._typing import _TypedColumnClauseArgument as _TCCA
+ from ..sql.base import Executable
+ from ..sql.dml import UpdateBase
+ from ..sql.elements import ClauseElement
+ from ..sql.roles import TypedColumnsClauseRole
+ from ..sql.selectable import ForUpdateParameter
+ from ..sql.selectable import TypedReturnsRows
+
+_T = TypeVar("_T", bound=Any)
+
+
+class QueryPropertyDescriptor(Protocol):
+ """Describes the type applied to a class-level
+ :meth:`_orm.scoped_session.query_property` attribute.
+
+ .. versionadded:: 2.0.5
+
+ """
+
+ def __get__(self, instance: Any, owner: Type[_T]) -> Query[_T]: ...
+
+
+_O = TypeVar("_O", bound=object)
+
+__all__ = ["scoped_session"]
+
+
+@create_proxy_methods(
+ Session,
+ ":class:`_orm.Session`",
+ ":class:`_orm.scoping.scoped_session`",
+ classmethods=["close_all", "object_session", "identity_key"],
+ methods=[
+ "__contains__",
+ "__iter__",
+ "add",
+ "add_all",
+ "begin",
+ "begin_nested",
+ "close",
+ "reset",
+ "commit",
+ "connection",
+ "delete",
+ "execute",
+ "expire",
+ "expire_all",
+ "expunge",
+ "expunge_all",
+ "flush",
+ "get",
+ "get_one",
+ "get_bind",
+ "is_modified",
+ "bulk_save_objects",
+ "bulk_insert_mappings",
+ "bulk_update_mappings",
+ "merge",
+ "query",
+ "refresh",
+ "rollback",
+ "scalar",
+ "scalars",
+ ],
+ attributes=[
+ "bind",
+ "dirty",
+ "deleted",
+ "new",
+ "identity_map",
+ "is_active",
+ "autoflush",
+ "no_autoflush",
+ "info",
+ ],
+)
+class scoped_session(Generic[_S]):
+ """Provides scoped management of :class:`.Session` objects.
+
+ See :ref:`unitofwork_contextual` for a tutorial.
+
+ .. note::
+
+ When using :ref:`asyncio_toplevel`, the async-compatible
+ :class:`_asyncio.async_scoped_session` class should be
+ used in place of :class:`.scoped_session`.
+
+ """
+
+ _support_async: bool = False
+
+ session_factory: sessionmaker[_S]
+ """The `session_factory` provided to `__init__` is stored in this
+ attribute and may be accessed at a later time. This can be useful when
+ a new non-scoped :class:`.Session` is needed."""
+
+ registry: ScopedRegistry[_S]
+
+ def __init__(
+ self,
+ session_factory: sessionmaker[_S],
+ scopefunc: Optional[Callable[[], Any]] = None,
+ ):
+ """Construct a new :class:`.scoped_session`.
+
+ :param session_factory: a factory to create new :class:`.Session`
+ instances. This is usually, but not necessarily, an instance
+ of :class:`.sessionmaker`.
+ :param scopefunc: optional function which defines
+ the current scope. If not passed, the :class:`.scoped_session`
+ object assumes "thread-local" scope, and will use
+ a Python ``threading.local()`` in order to maintain the current
+ :class:`.Session`. If passed, the function should return
+ a hashable token; this token will be used as the key in a
+ dictionary in order to store and retrieve the current
+ :class:`.Session`.
+
+ """
+ self.session_factory = session_factory
+
+ if scopefunc:
+ self.registry = ScopedRegistry(session_factory, scopefunc)
+ else:
+ self.registry = ThreadLocalRegistry(session_factory)
+
+ @property
+ def _proxied(self) -> _S:
+ return self.registry()
+
+ def __call__(self, **kw: Any) -> _S:
+ r"""Return the current :class:`.Session`, creating it
+ using the :attr:`.scoped_session.session_factory` if not present.
+
+ :param \**kw: Keyword arguments will be passed to the
+ :attr:`.scoped_session.session_factory` callable, if an existing
+ :class:`.Session` is not present. If the :class:`.Session` is present
+ and keyword arguments have been passed,
+ :exc:`~sqlalchemy.exc.InvalidRequestError` is raised.
+
+ """
+ if kw:
+ if self.registry.has():
+ raise sa_exc.InvalidRequestError(
+ "Scoped session is already present; "
+ "no new arguments may be specified."
+ )
+ else:
+ sess = self.session_factory(**kw)
+ self.registry.set(sess)
+ else:
+ sess = self.registry()
+ if not self._support_async and sess._is_asyncio:
+ warn_deprecated(
+ "Using `scoped_session` with asyncio is deprecated and "
+ "will raise an error in a future version. "
+ "Please use `async_scoped_session` instead.",
+ "1.4.23",
+ )
+ return sess
+
+ def configure(self, **kwargs: Any) -> None:
+ """reconfigure the :class:`.sessionmaker` used by this
+ :class:`.scoped_session`.
+
+ See :meth:`.sessionmaker.configure`.
+
+ """
+
+ if self.registry.has():
+ warn(
+ "At least one scoped session is already present. "
+ " configure() can not affect sessions that have "
+ "already been created."
+ )
+
+ self.session_factory.configure(**kwargs)
+
+ def remove(self) -> None:
+ """Dispose of the current :class:`.Session`, if present.
+
+ This will first call :meth:`.Session.close` method
+ on the current :class:`.Session`, which releases any existing
+ transactional/connection resources still being held; transactions
+ specifically are rolled back. The :class:`.Session` is then
+ discarded. Upon next usage within the same scope,
+ the :class:`.scoped_session` will produce a new
+ :class:`.Session` object.
+
+ """
+
+ if self.registry.has():
+ self.registry().close()
+ self.registry.clear()
+
+ def query_property(
+ self, query_cls: Optional[Type[Query[_T]]] = None
+ ) -> QueryPropertyDescriptor:
+ """return a class property which produces a legacy
+ :class:`_query.Query` object against the class and the current
+ :class:`.Session` when called.
+
+ .. legacy:: The :meth:`_orm.scoped_session.query_property` accessor
+ is specific to the legacy :class:`.Query` object and is not
+ considered to be part of :term:`2.0-style` ORM use.
+
+ e.g.::
+
+ from sqlalchemy.orm import QueryPropertyDescriptor
+ from sqlalchemy.orm import scoped_session
+ from sqlalchemy.orm import sessionmaker
+
+ Session = scoped_session(sessionmaker())
+
+ class MyClass:
+ query: QueryPropertyDescriptor = Session.query_property()
+
+ # after mappers are defined
+ result = MyClass.query.filter(MyClass.name=='foo').all()
+
+ Produces instances of the session's configured query class by
+ default. To override and use a custom implementation, provide
+ a ``query_cls`` callable. The callable will be invoked with
+ the class's mapper as a positional argument and a session
+ keyword argument.
+
+ There is no limit to the number of query properties placed on
+ a class.
+
+ """
+
+ class query:
+ def __get__(s, instance: Any, owner: Type[_O]) -> Query[_O]:
+ if query_cls:
+ # custom query class
+ return query_cls(owner, session=self.registry()) # type: ignore # noqa: E501
+ else:
+ # session's configured query class
+ return self.registry().query(owner)
+
+ return query()
+
+ # START PROXY METHODS scoped_session
+
+ # code within this block is **programmatically,
+ # statically generated** by tools/generate_proxy_methods.py
+
+ def __contains__(self, instance: object) -> bool:
+ r"""Return True if the instance is associated with this session.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ The instance may be pending or persistent within the Session for a
+ result of True.
+
+
+ """ # noqa: E501
+
+ return self._proxied.__contains__(instance)
+
+ def __iter__(self) -> Iterator[object]:
+ r"""Iterate over all pending or persistent instances within this
+ Session.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+
+ """ # noqa: E501
+
+ return self._proxied.__iter__()
+
+ def add(self, instance: object, _warn: bool = True) -> None:
+ r"""Place an object into this :class:`_orm.Session`.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Objects that are in the :term:`transient` state when passed to the
+ :meth:`_orm.Session.add` method will move to the
+ :term:`pending` state, until the next flush, at which point they
+ will move to the :term:`persistent` state.
+
+ Objects that are in the :term:`detached` state when passed to the
+ :meth:`_orm.Session.add` method will move to the :term:`persistent`
+ state directly.
+
+ If the transaction used by the :class:`_orm.Session` is rolled back,
+ objects which were transient when they were passed to
+ :meth:`_orm.Session.add` will be moved back to the
+ :term:`transient` state, and will no longer be present within this
+ :class:`_orm.Session`.
+
+ .. seealso::
+
+ :meth:`_orm.Session.add_all`
+
+ :ref:`session_adding` - at :ref:`session_basics`
+
+
+ """ # noqa: E501
+
+ return self._proxied.add(instance, _warn=_warn)
+
+ def add_all(self, instances: Iterable[object]) -> None:
+ r"""Add the given collection of instances to this :class:`_orm.Session`.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ See the documentation for :meth:`_orm.Session.add` for a general
+ behavioral description.
+
+ .. seealso::
+
+ :meth:`_orm.Session.add`
+
+ :ref:`session_adding` - at :ref:`session_basics`
+
+
+ """ # noqa: E501
+
+ return self._proxied.add_all(instances)
+
+ def begin(self, nested: bool = False) -> SessionTransaction:
+ r"""Begin a transaction, or nested transaction,
+ on this :class:`.Session`, if one is not already begun.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ The :class:`_orm.Session` object features **autobegin** behavior,
+ so that normally it is not necessary to call the
+ :meth:`_orm.Session.begin`
+ method explicitly. However, it may be used in order to control
+ the scope of when the transactional state is begun.
+
+ When used to begin the outermost transaction, an error is raised
+ if this :class:`.Session` is already inside of a transaction.
+
+ :param nested: if True, begins a SAVEPOINT transaction and is
+ equivalent to calling :meth:`~.Session.begin_nested`. For
+ documentation on SAVEPOINT transactions, please see
+ :ref:`session_begin_nested`.
+
+ :return: the :class:`.SessionTransaction` object. Note that
+ :class:`.SessionTransaction`
+ acts as a Python context manager, allowing :meth:`.Session.begin`
+ to be used in a "with" block. See :ref:`session_explicit_begin` for
+ an example.
+
+ .. seealso::
+
+ :ref:`session_autobegin`
+
+ :ref:`unitofwork_transaction`
+
+ :meth:`.Session.begin_nested`
+
+
+
+ """ # noqa: E501
+
+ return self._proxied.begin(nested=nested)
+
+ def begin_nested(self) -> SessionTransaction:
+ r"""Begin a "nested" transaction on this Session, e.g. SAVEPOINT.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ The target database(s) and associated drivers must support SQL
+ SAVEPOINT for this method to function correctly.
+
+ For documentation on SAVEPOINT
+ transactions, please see :ref:`session_begin_nested`.
+
+ :return: the :class:`.SessionTransaction` object. Note that
+ :class:`.SessionTransaction` acts as a context manager, allowing
+ :meth:`.Session.begin_nested` to be used in a "with" block.
+ See :ref:`session_begin_nested` for a usage example.
+
+ .. seealso::
+
+ :ref:`session_begin_nested`
+
+ :ref:`pysqlite_serializable` - special workarounds required
+ with the SQLite driver in order for SAVEPOINT to work
+ correctly. For asyncio use cases, see the section
+ :ref:`aiosqlite_serializable`.
+
+
+ """ # noqa: E501
+
+ return self._proxied.begin_nested()
+
+ def close(self) -> None:
+ r"""Close out the transactional resources and ORM objects used by this
+ :class:`_orm.Session`.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ This expunges all ORM objects associated with this
+ :class:`_orm.Session`, ends any transaction in progress and
+ :term:`releases` any :class:`_engine.Connection` objects which this
+ :class:`_orm.Session` itself has checked out from associated
+ :class:`_engine.Engine` objects. The operation then leaves the
+ :class:`_orm.Session` in a state which it may be used again.
+
+ .. tip::
+
+ In the default running mode the :meth:`_orm.Session.close`
+ method **does not prevent the Session from being used again**.
+ The :class:`_orm.Session` itself does not actually have a
+ distinct "closed" state; it merely means
+ the :class:`_orm.Session` will release all database connections
+ and ORM objects.
+
+ Setting the parameter :paramref:`_orm.Session.close_resets_only`
+ to ``False`` will instead make the ``close`` final, meaning that
+ any further action on the session will be forbidden.
+
+ .. versionchanged:: 1.4 The :meth:`.Session.close` method does not
+ immediately create a new :class:`.SessionTransaction` object;
+ instead, the new :class:`.SessionTransaction` is created only if
+ the :class:`.Session` is used again for a database operation.
+
+ .. seealso::
+
+ :ref:`session_closing` - detail on the semantics of
+ :meth:`_orm.Session.close` and :meth:`_orm.Session.reset`.
+
+ :meth:`_orm.Session.reset` - a similar method that behaves like
+ ``close()`` with the parameter
+ :paramref:`_orm.Session.close_resets_only` set to ``True``.
+
+
+ """ # noqa: E501
+
+ return self._proxied.close()
+
+ def reset(self) -> None:
+ r"""Close out the transactional resources and ORM objects used by this
+ :class:`_orm.Session`, resetting the session to its initial state.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ This method provides for same "reset-only" behavior that the
+ :meth:`_orm.Session.close` method has provided historically, where the
+ state of the :class:`_orm.Session` is reset as though the object were
+ brand new, and ready to be used again.
+ This method may then be useful for :class:`_orm.Session` objects
+ which set :paramref:`_orm.Session.close_resets_only` to ``False``,
+ so that "reset only" behavior is still available.
+
+ .. versionadded:: 2.0.22
+
+ .. seealso::
+
+ :ref:`session_closing` - detail on the semantics of
+ :meth:`_orm.Session.close` and :meth:`_orm.Session.reset`.
+
+ :meth:`_orm.Session.close` - a similar method will additionally
+ prevent re-use of the Session when the parameter
+ :paramref:`_orm.Session.close_resets_only` is set to ``False``.
+
+ """ # noqa: E501
+
+ return self._proxied.reset()
+
+ def commit(self) -> None:
+ r"""Flush pending changes and commit the current transaction.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ When the COMMIT operation is complete, all objects are fully
+ :term:`expired`, erasing their internal contents, which will be
+ automatically re-loaded when the objects are next accessed. In the
+ interim, these objects are in an expired state and will not function if
+ they are :term:`detached` from the :class:`.Session`. Additionally,
+ this re-load operation is not supported when using asyncio-oriented
+ APIs. The :paramref:`.Session.expire_on_commit` parameter may be used
+ to disable this behavior.
+
+ When there is no transaction in place for the :class:`.Session`,
+ indicating that no operations were invoked on this :class:`.Session`
+ since the previous call to :meth:`.Session.commit`, the method will
+ begin and commit an internal-only "logical" transaction, that does not
+ normally affect the database unless pending flush changes were
+ detected, but will still invoke event handlers and object expiration
+ rules.
+
+ The outermost database transaction is committed unconditionally,
+ automatically releasing any SAVEPOINTs in effect.
+
+ .. seealso::
+
+ :ref:`session_committing`
+
+ :ref:`unitofwork_transaction`
+
+ :ref:`asyncio_orm_avoid_lazyloads`
+
+
+ """ # noqa: E501
+
+ return self._proxied.commit()
+
+ def connection(
+ self,
+ bind_arguments: Optional[_BindArguments] = None,
+ execution_options: Optional[CoreExecuteOptionsParameter] = None,
+ ) -> Connection:
+ r"""Return a :class:`_engine.Connection` object corresponding to this
+ :class:`.Session` object's transactional state.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Either the :class:`_engine.Connection` corresponding to the current
+ transaction is returned, or if no transaction is in progress, a new
+ one is begun and the :class:`_engine.Connection`
+ returned (note that no
+ transactional state is established with the DBAPI until the first
+ SQL statement is emitted).
+
+ Ambiguity in multi-bind or unbound :class:`.Session` objects can be
+ resolved through any of the optional keyword arguments. This
+ ultimately makes usage of the :meth:`.get_bind` method for resolution.
+
+ :param bind_arguments: dictionary of bind arguments. May include
+ "mapper", "bind", "clause", other custom arguments that are passed
+ to :meth:`.Session.get_bind`.
+
+ :param execution_options: a dictionary of execution options that will
+ be passed to :meth:`_engine.Connection.execution_options`, **when the
+ connection is first procured only**. If the connection is already
+ present within the :class:`.Session`, a warning is emitted and
+ the arguments are ignored.
+
+ .. seealso::
+
+ :ref:`session_transaction_isolation`
+
+
+ """ # noqa: E501
+
+ return self._proxied.connection(
+ bind_arguments=bind_arguments, execution_options=execution_options
+ )
+
+ def delete(self, instance: object) -> None:
+ r"""Mark an instance as deleted.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ The object is assumed to be either :term:`persistent` or
+ :term:`detached` when passed; after the method is called, the
+ object will remain in the :term:`persistent` state until the next
+ flush proceeds. During this time, the object will also be a member
+ of the :attr:`_orm.Session.deleted` collection.
+
+ When the next flush proceeds, the object will move to the
+ :term:`deleted` state, indicating a ``DELETE`` statement was emitted
+ for its row within the current transaction. When the transaction
+ is successfully committed,
+ the deleted object is moved to the :term:`detached` state and is
+ no longer present within this :class:`_orm.Session`.
+
+ .. seealso::
+
+ :ref:`session_deleting` - at :ref:`session_basics`
+
+
+ """ # noqa: E501
+
+ return self._proxied.delete(instance)
+
+ @overload
+ def execute(
+ self,
+ statement: TypedReturnsRows[_T],
+ params: Optional[_CoreAnyExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ _parent_execute_state: Optional[Any] = None,
+ _add_event: Optional[Any] = None,
+ ) -> Result[_T]: ...
+
+ @overload
+ def execute(
+ self,
+ statement: UpdateBase,
+ params: Optional[_CoreAnyExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ _parent_execute_state: Optional[Any] = None,
+ _add_event: Optional[Any] = None,
+ ) -> CursorResult[Any]: ...
+
+ @overload
+ def execute(
+ self,
+ statement: Executable,
+ params: Optional[_CoreAnyExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ _parent_execute_state: Optional[Any] = None,
+ _add_event: Optional[Any] = None,
+ ) -> Result[Any]: ...
+
+ def execute(
+ self,
+ statement: Executable,
+ params: Optional[_CoreAnyExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ _parent_execute_state: Optional[Any] = None,
+ _add_event: Optional[Any] = None,
+ ) -> Result[Any]:
+ r"""Execute a SQL expression construct.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Returns a :class:`_engine.Result` object representing
+ results of the statement execution.
+
+ E.g.::
+
+ from sqlalchemy import select
+ result = session.execute(
+ select(User).where(User.id == 5)
+ )
+
+ The API contract of :meth:`_orm.Session.execute` is similar to that
+ of :meth:`_engine.Connection.execute`, the :term:`2.0 style` version
+ of :class:`_engine.Connection`.
+
+ .. versionchanged:: 1.4 the :meth:`_orm.Session.execute` method is
+ now the primary point of ORM statement execution when using
+ :term:`2.0 style` ORM usage.
+
+ :param statement:
+ An executable statement (i.e. an :class:`.Executable` expression
+ such as :func:`_expression.select`).
+
+ :param params:
+ Optional dictionary, or list of dictionaries, containing
+ bound parameter values. If a single dictionary, single-row
+ execution occurs; if a list of dictionaries, an
+ "executemany" will be invoked. The keys in each dictionary
+ must correspond to parameter names present in the statement.
+
+ :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`, and may also
+ provide additional options understood only in an ORM context.
+
+ .. seealso::
+
+ :ref:`orm_queryguide_execution_options` - ORM-specific execution
+ options
+
+ :param bind_arguments: dictionary of additional arguments to determine
+ the bind. May include "mapper", "bind", or other custom arguments.
+ Contents of this dictionary are passed to the
+ :meth:`.Session.get_bind` method.
+
+ :return: a :class:`_engine.Result` object.
+
+
+
+ """ # noqa: E501
+
+ return self._proxied.execute(
+ statement,
+ params=params,
+ execution_options=execution_options,
+ bind_arguments=bind_arguments,
+ _parent_execute_state=_parent_execute_state,
+ _add_event=_add_event,
+ )
+
+ def expire(
+ self, instance: object, attribute_names: Optional[Iterable[str]] = None
+ ) -> None:
+ r"""Expire the attributes on an instance.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Marks the attributes of an instance as out of date. When an expired
+ attribute is next accessed, a query will be issued to the
+ :class:`.Session` object's current transactional context in order to
+ load all expired attributes for the given instance. Note that
+ a highly isolated transaction will return the same values as were
+ previously read in that same transaction, regardless of changes
+ in database state outside of that transaction.
+
+ To expire all objects in the :class:`.Session` simultaneously,
+ use :meth:`Session.expire_all`.
+
+ The :class:`.Session` object's default behavior is to
+ expire all state whenever the :meth:`Session.rollback`
+ or :meth:`Session.commit` methods are called, so that new
+ state can be loaded for the new transaction. For this reason,
+ calling :meth:`Session.expire` only makes sense for the specific
+ case that a non-ORM SQL statement was emitted in the current
+ transaction.
+
+ :param instance: The instance to be refreshed.
+ :param attribute_names: optional list of string attribute names
+ indicating a subset of attributes to be expired.
+
+ .. seealso::
+
+ :ref:`session_expire` - introductory material
+
+ :meth:`.Session.expire`
+
+ :meth:`.Session.refresh`
+
+ :meth:`_orm.Query.populate_existing`
+
+
+ """ # noqa: E501
+
+ return self._proxied.expire(instance, attribute_names=attribute_names)
+
+ def expire_all(self) -> None:
+ r"""Expires all persistent instances within this Session.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ When any attributes on a persistent instance is next accessed,
+ a query will be issued using the
+ :class:`.Session` object's current transactional context in order to
+ load all expired attributes for the given instance. Note that
+ a highly isolated transaction will return the same values as were
+ previously read in that same transaction, regardless of changes
+ in database state outside of that transaction.
+
+ To expire individual objects and individual attributes
+ on those objects, use :meth:`Session.expire`.
+
+ The :class:`.Session` object's default behavior is to
+ expire all state whenever the :meth:`Session.rollback`
+ or :meth:`Session.commit` methods are called, so that new
+ state can be loaded for the new transaction. For this reason,
+ calling :meth:`Session.expire_all` is not usually needed,
+ assuming the transaction is isolated.
+
+ .. seealso::
+
+ :ref:`session_expire` - introductory material
+
+ :meth:`.Session.expire`
+
+ :meth:`.Session.refresh`
+
+ :meth:`_orm.Query.populate_existing`
+
+
+ """ # noqa: E501
+
+ return self._proxied.expire_all()
+
+ def expunge(self, instance: object) -> None:
+ r"""Remove the `instance` from this ``Session``.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ This will free all internal references to the instance. Cascading
+ will be applied according to the *expunge* cascade rule.
+
+
+ """ # noqa: E501
+
+ return self._proxied.expunge(instance)
+
+ def expunge_all(self) -> None:
+ r"""Remove all object instances from this ``Session``.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ This is equivalent to calling ``expunge(obj)`` on all objects in this
+ ``Session``.
+
+
+ """ # noqa: E501
+
+ return self._proxied.expunge_all()
+
+ def flush(self, objects: Optional[Sequence[Any]] = None) -> None:
+ r"""Flush all the object changes to the database.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Writes out all pending object creations, deletions and modifications
+ to the database as INSERTs, DELETEs, UPDATEs, etc. Operations are
+ automatically ordered by the Session's unit of work dependency
+ solver.
+
+ Database operations will be issued in the current transactional
+ context and do not affect the state of the transaction, unless an
+ error occurs, in which case the entire transaction is rolled back.
+ You may flush() as often as you like within a transaction to move
+ changes from Python to the database's transaction buffer.
+
+ :param objects: Optional; restricts the flush operation to operate
+ only on elements that are in the given collection.
+
+ This feature is for an extremely narrow set of use cases where
+ particular objects may need to be operated upon before the
+ full flush() occurs. It is not intended for general use.
+
+
+ """ # noqa: E501
+
+ return self._proxied.flush(objects=objects)
+
+ def get(
+ self,
+ entity: _EntityBindKey[_O],
+ ident: _PKIdentityArgument,
+ *,
+ options: Optional[Sequence[ORMOption]] = None,
+ populate_existing: bool = False,
+ with_for_update: ForUpdateParameter = None,
+ identity_token: Optional[Any] = None,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ ) -> Optional[_O]:
+ r"""Return an instance based on the given primary key identifier,
+ or ``None`` if not found.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ E.g.::
+
+ my_user = session.get(User, 5)
+
+ some_object = session.get(VersionedFoo, (5, 10))
+
+ some_object = session.get(
+ VersionedFoo,
+ {"id": 5, "version_id": 10}
+ )
+
+ .. versionadded:: 1.4 Added :meth:`_orm.Session.get`, which is moved
+ from the now legacy :meth:`_orm.Query.get` method.
+
+ :meth:`_orm.Session.get` is special in that it provides direct
+ access to the identity map of the :class:`.Session`.
+ If the given primary key identifier is present
+ in the local identity map, the object is returned
+ directly from this collection and no SQL is emitted,
+ unless the object has been marked fully expired.
+ If not present,
+ a SELECT is performed in order to locate the object.
+
+ :meth:`_orm.Session.get` also will perform a check if
+ the object is present in the identity map and
+ marked as expired - a SELECT
+ is emitted to refresh the object as well as to
+ ensure that the row is still present.
+ If not, :class:`~sqlalchemy.orm.exc.ObjectDeletedError` is raised.
+
+ :param entity: a mapped class or :class:`.Mapper` indicating the
+ type of entity to be loaded.
+
+ :param ident: A scalar, tuple, or dictionary representing the
+ primary key. For a composite (e.g. multiple column) primary key,
+ a tuple or dictionary should be passed.
+
+ For a single-column primary key, the scalar calling form is typically
+ the most expedient. If the primary key of a row is the value "5",
+ the call looks like::
+
+ my_object = session.get(SomeClass, 5)
+
+ The tuple form contains primary key values typically in
+ the order in which they correspond to the mapped
+ :class:`_schema.Table`
+ object's primary key columns, or if the
+ :paramref:`_orm.Mapper.primary_key` configuration parameter were
+ used, in
+ the order used for that parameter. For example, if the primary key
+ of a row is represented by the integer
+ digits "5, 10" the call would look like::
+
+ my_object = session.get(SomeClass, (5, 10))
+
+ The dictionary form should include as keys the mapped attribute names
+ corresponding to each element of the primary key. If the mapped class
+ has the attributes ``id``, ``version_id`` as the attributes which
+ store the object's primary key value, the call would look like::
+
+ my_object = session.get(SomeClass, {"id": 5, "version_id": 10})
+
+ :param options: optional sequence of loader options which will be
+ applied to the query, if one is emitted.
+
+ :param populate_existing: causes the method to unconditionally emit
+ a SQL query and refresh the object with the newly loaded data,
+ regardless of whether or not the object is already present.
+
+ :param with_for_update: optional boolean ``True`` indicating FOR UPDATE
+ should be used, or may be a dictionary containing flags to
+ indicate a more specific set of FOR UPDATE flags for the SELECT;
+ flags should match the parameters of
+ :meth:`_query.Query.with_for_update`.
+ Supersedes the :paramref:`.Session.refresh.lockmode` parameter.
+
+ :param execution_options: optional dictionary of execution options,
+ which will be associated with the query execution if one is emitted.
+ This dictionary can provide a subset of the options that are
+ accepted by :meth:`_engine.Connection.execution_options`, and may
+ also provide additional options understood only in an ORM context.
+
+ .. versionadded:: 1.4.29
+
+ .. seealso::
+
+ :ref:`orm_queryguide_execution_options` - ORM-specific execution
+ options
+
+ :param bind_arguments: dictionary of additional arguments to determine
+ the bind. May include "mapper", "bind", or other custom arguments.
+ Contents of this dictionary are passed to the
+ :meth:`.Session.get_bind` method.
+
+ .. versionadded: 2.0.0rc1
+
+ :return: The object instance, or ``None``.
+
+
+ """ # noqa: E501
+
+ return self._proxied.get(
+ entity,
+ ident,
+ options=options,
+ populate_existing=populate_existing,
+ with_for_update=with_for_update,
+ identity_token=identity_token,
+ execution_options=execution_options,
+ bind_arguments=bind_arguments,
+ )
+
+ def get_one(
+ self,
+ entity: _EntityBindKey[_O],
+ ident: _PKIdentityArgument,
+ *,
+ options: Optional[Sequence[ORMOption]] = None,
+ populate_existing: bool = False,
+ with_for_update: ForUpdateParameter = None,
+ identity_token: Optional[Any] = None,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ ) -> _O:
+ r"""Return exactly one instance based on the given primary key
+ identifier, or raise an exception if not found.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Raises ``sqlalchemy.orm.exc.NoResultFound`` if the query
+ selects no rows.
+
+ For a detailed documentation of the arguments see the
+ method :meth:`.Session.get`.
+
+ .. versionadded:: 2.0.22
+
+ :return: The object instance.
+
+ .. seealso::
+
+ :meth:`.Session.get` - equivalent method that instead
+ returns ``None`` if no row was found with the provided primary
+ key
+
+
+ """ # noqa: E501
+
+ return self._proxied.get_one(
+ entity,
+ ident,
+ options=options,
+ populate_existing=populate_existing,
+ with_for_update=with_for_update,
+ identity_token=identity_token,
+ execution_options=execution_options,
+ bind_arguments=bind_arguments,
+ )
+
+ def get_bind(
+ self,
+ mapper: Optional[_EntityBindKey[_O]] = None,
+ *,
+ clause: Optional[ClauseElement] = None,
+ bind: Optional[_SessionBind] = None,
+ _sa_skip_events: Optional[bool] = None,
+ _sa_skip_for_implicit_returning: bool = False,
+ **kw: Any,
+ ) -> Union[Engine, Connection]:
+ r"""Return a "bind" to which this :class:`.Session` is bound.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ The "bind" is usually an instance of :class:`_engine.Engine`,
+ except in the case where the :class:`.Session` has been
+ explicitly bound directly to a :class:`_engine.Connection`.
+
+ For a multiply-bound or unbound :class:`.Session`, the
+ ``mapper`` or ``clause`` arguments are used to determine the
+ appropriate bind to return.
+
+ Note that the "mapper" argument is usually present
+ when :meth:`.Session.get_bind` is called via an ORM
+ operation such as a :meth:`.Session.query`, each
+ individual INSERT/UPDATE/DELETE operation within a
+ :meth:`.Session.flush`, call, etc.
+
+ The order of resolution is:
+
+ 1. if mapper given and :paramref:`.Session.binds` is present,
+ locate a bind based first on the mapper in use, then
+ on the mapped class in use, then on any base classes that are
+ present in the ``__mro__`` of the mapped class, from more specific
+ superclasses to more general.
+ 2. if clause given and ``Session.binds`` is present,
+ locate a bind based on :class:`_schema.Table` objects
+ found in the given clause present in ``Session.binds``.
+ 3. if ``Session.binds`` is present, return that.
+ 4. if clause given, attempt to return a bind
+ linked to the :class:`_schema.MetaData` ultimately
+ associated with the clause.
+ 5. if mapper given, attempt to return a bind
+ linked to the :class:`_schema.MetaData` ultimately
+ associated with the :class:`_schema.Table` or other
+ selectable to which the mapper is mapped.
+ 6. No bind can be found, :exc:`~sqlalchemy.exc.UnboundExecutionError`
+ is raised.
+
+ Note that the :meth:`.Session.get_bind` method can be overridden on
+ a user-defined subclass of :class:`.Session` to provide any kind
+ of bind resolution scheme. See the example at
+ :ref:`session_custom_partitioning`.
+
+ :param mapper:
+ Optional mapped class or corresponding :class:`_orm.Mapper` instance.
+ The bind can be derived from a :class:`_orm.Mapper` first by
+ consulting the "binds" map associated with this :class:`.Session`,
+ and secondly by consulting the :class:`_schema.MetaData` associated
+ with the :class:`_schema.Table` to which the :class:`_orm.Mapper` is
+ mapped for a bind.
+
+ :param clause:
+ A :class:`_expression.ClauseElement` (i.e.
+ :func:`_expression.select`,
+ :func:`_expression.text`,
+ etc.). If the ``mapper`` argument is not present or could not
+ produce a bind, the given expression construct will be searched
+ for a bound element, typically a :class:`_schema.Table`
+ associated with
+ bound :class:`_schema.MetaData`.
+
+ .. seealso::
+
+ :ref:`session_partitioning`
+
+ :paramref:`.Session.binds`
+
+ :meth:`.Session.bind_mapper`
+
+ :meth:`.Session.bind_table`
+
+
+ """ # noqa: E501
+
+ return self._proxied.get_bind(
+ mapper=mapper,
+ clause=clause,
+ bind=bind,
+ _sa_skip_events=_sa_skip_events,
+ _sa_skip_for_implicit_returning=_sa_skip_for_implicit_returning,
+ **kw,
+ )
+
+ def is_modified(
+ self, instance: object, include_collections: bool = True
+ ) -> bool:
+ r"""Return ``True`` if the given instance has locally
+ modified attributes.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ This method retrieves the history for each instrumented
+ attribute on the instance and performs a comparison of the current
+ value to its previously committed value, if any.
+
+ It is in effect a more expensive and accurate
+ version of checking for the given instance in the
+ :attr:`.Session.dirty` collection; a full test for
+ each attribute's net "dirty" status is performed.
+
+ E.g.::
+
+ return session.is_modified(someobject)
+
+ A few caveats to this method apply:
+
+ * Instances present in the :attr:`.Session.dirty` collection may
+ report ``False`` when tested with this method. This is because
+ the object may have received change events via attribute mutation,
+ thus placing it in :attr:`.Session.dirty`, but ultimately the state
+ is the same as that loaded from the database, resulting in no net
+ change here.
+ * Scalar attributes may not have recorded the previously set
+ value when a new value was applied, if the attribute was not loaded,
+ or was expired, at the time the new value was received - in these
+ cases, the attribute is assumed to have a change, even if there is
+ ultimately no net change against its database value. SQLAlchemy in
+ most cases does not need the "old" value when a set event occurs, so
+ it skips the expense of a SQL call if the old value isn't present,
+ based on the assumption that an UPDATE of the scalar value is
+ usually needed, and in those few cases where it isn't, is less
+ expensive on average than issuing a defensive SELECT.
+
+ The "old" value is fetched unconditionally upon set only if the
+ attribute container has the ``active_history`` flag set to ``True``.
+ This flag is set typically for primary key attributes and scalar
+ object references that are not a simple many-to-one. To set this
+ flag for any arbitrary mapped column, use the ``active_history``
+ argument with :func:`.column_property`.
+
+ :param instance: mapped instance to be tested for pending changes.
+ :param include_collections: Indicates if multivalued collections
+ should be included in the operation. Setting this to ``False`` is a
+ way to detect only local-column based properties (i.e. scalar columns
+ or many-to-one foreign keys) that would result in an UPDATE for this
+ instance upon flush.
+
+
+ """ # noqa: E501
+
+ return self._proxied.is_modified(
+ instance, include_collections=include_collections
+ )
+
+ def bulk_save_objects(
+ self,
+ objects: Iterable[object],
+ return_defaults: bool = False,
+ update_changed_only: bool = True,
+ preserve_order: bool = True,
+ ) -> None:
+ r"""Perform a bulk save of the given list of objects.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ .. legacy::
+
+ This method is a legacy feature as of the 2.0 series of
+ SQLAlchemy. For modern bulk INSERT and UPDATE, see
+ the sections :ref:`orm_queryguide_bulk_insert` and
+ :ref:`orm_queryguide_bulk_update`.
+
+ For general INSERT and UPDATE of existing ORM mapped objects,
+ prefer standard :term:`unit of work` data management patterns,
+ introduced in the :ref:`unified_tutorial` at
+ :ref:`tutorial_orm_data_manipulation`. SQLAlchemy 2.0
+ now uses :ref:`engine_insertmanyvalues` with modern dialects
+ which solves previous issues of bulk INSERT slowness.
+
+ :param objects: a sequence of mapped object instances. The mapped
+ objects are persisted as is, and are **not** associated with the
+ :class:`.Session` afterwards.
+
+ For each object, whether the object is sent as an INSERT or an
+ UPDATE is dependent on the same rules used by the :class:`.Session`
+ in traditional operation; if the object has the
+ :attr:`.InstanceState.key`
+ attribute set, then the object is assumed to be "detached" and
+ will result in an UPDATE. Otherwise, an INSERT is used.
+
+ In the case of an UPDATE, statements are grouped based on which
+ attributes have changed, and are thus to be the subject of each
+ SET clause. If ``update_changed_only`` is False, then all
+ attributes present within each object are applied to the UPDATE
+ statement, which may help in allowing the statements to be grouped
+ together into a larger executemany(), and will also reduce the
+ overhead of checking history on attributes.
+
+ :param return_defaults: when True, rows that are missing values which
+ generate defaults, namely integer primary key defaults and sequences,
+ will be inserted **one at a time**, so that the primary key value
+ is available. In particular this will allow joined-inheritance
+ and other multi-table mappings to insert correctly without the need
+ to provide primary key values ahead of time; however,
+ :paramref:`.Session.bulk_save_objects.return_defaults` **greatly
+ reduces the performance gains** of the method overall. It is strongly
+ advised to please use the standard :meth:`_orm.Session.add_all`
+ approach.
+
+ :param update_changed_only: when True, UPDATE statements are rendered
+ based on those attributes in each state that have logged changes.
+ When False, all attributes present are rendered into the SET clause
+ with the exception of primary key attributes.
+
+ :param preserve_order: when True, the order of inserts and updates
+ matches exactly the order in which the objects are given. When
+ False, common types of objects are grouped into inserts
+ and updates, to allow for more batching opportunities.
+
+ .. seealso::
+
+ :doc:`queryguide/dml`
+
+ :meth:`.Session.bulk_insert_mappings`
+
+ :meth:`.Session.bulk_update_mappings`
+
+
+ """ # noqa: E501
+
+ return self._proxied.bulk_save_objects(
+ objects,
+ return_defaults=return_defaults,
+ update_changed_only=update_changed_only,
+ preserve_order=preserve_order,
+ )
+
+ def bulk_insert_mappings(
+ self,
+ mapper: Mapper[Any],
+ mappings: Iterable[Dict[str, Any]],
+ return_defaults: bool = False,
+ render_nulls: bool = False,
+ ) -> None:
+ r"""Perform a bulk insert of the given list of mapping dictionaries.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ .. legacy::
+
+ This method is a legacy feature as of the 2.0 series of
+ SQLAlchemy. For modern bulk INSERT and UPDATE, see
+ the sections :ref:`orm_queryguide_bulk_insert` and
+ :ref:`orm_queryguide_bulk_update`. The 2.0 API shares
+ implementation details with this method and adds new features
+ as well.
+
+ :param mapper: a mapped class, or the actual :class:`_orm.Mapper`
+ object,
+ representing the single kind of object represented within the mapping
+ list.
+
+ :param mappings: a sequence of dictionaries, each one containing the
+ state of the mapped row to be inserted, in terms of the attribute
+ names on the mapped class. If the mapping refers to multiple tables,
+ such as a joined-inheritance mapping, each dictionary must contain all
+ keys to be populated into all tables.
+
+ :param return_defaults: when True, the INSERT process will be altered
+ to ensure that newly generated primary key values will be fetched.
+ The rationale for this parameter is typically to enable
+ :ref:`Joined Table Inheritance <joined_inheritance>` mappings to
+ be bulk inserted.
+
+ .. note:: for backends that don't support RETURNING, the
+ :paramref:`_orm.Session.bulk_insert_mappings.return_defaults`
+ parameter can significantly decrease performance as INSERT
+ statements can no longer be batched. See
+ :ref:`engine_insertmanyvalues`
+ for background on which backends are affected.
+
+ :param render_nulls: When True, a value of ``None`` will result
+ in a NULL value being included in the INSERT statement, rather
+ than the column being omitted from the INSERT. This allows all
+ the rows being INSERTed to have the identical set of columns which
+ allows the full set of rows to be batched to the DBAPI. Normally,
+ each column-set that contains a different combination of NULL values
+ than the previous row must omit a different series of columns from
+ the rendered INSERT statement, which means it must be emitted as a
+ separate statement. By passing this flag, the full set of rows
+ are guaranteed to be batchable into one batch; the cost however is
+ that server-side defaults which are invoked by an omitted column will
+ be skipped, so care must be taken to ensure that these are not
+ necessary.
+
+ .. warning::
+
+ When this flag is set, **server side default SQL values will
+ not be invoked** for those columns that are inserted as NULL;
+ the NULL value will be sent explicitly. Care must be taken
+ to ensure that no server-side default functions need to be
+ invoked for the operation as a whole.
+
+ .. seealso::
+
+ :doc:`queryguide/dml`
+
+ :meth:`.Session.bulk_save_objects`
+
+ :meth:`.Session.bulk_update_mappings`
+
+
+ """ # noqa: E501
+
+ return self._proxied.bulk_insert_mappings(
+ mapper,
+ mappings,
+ return_defaults=return_defaults,
+ render_nulls=render_nulls,
+ )
+
+ def bulk_update_mappings(
+ self, mapper: Mapper[Any], mappings: Iterable[Dict[str, Any]]
+ ) -> None:
+ r"""Perform a bulk update of the given list of mapping dictionaries.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ .. legacy::
+
+ This method is a legacy feature as of the 2.0 series of
+ SQLAlchemy. For modern bulk INSERT and UPDATE, see
+ the sections :ref:`orm_queryguide_bulk_insert` and
+ :ref:`orm_queryguide_bulk_update`. The 2.0 API shares
+ implementation details with this method and adds new features
+ as well.
+
+ :param mapper: a mapped class, or the actual :class:`_orm.Mapper`
+ object,
+ representing the single kind of object represented within the mapping
+ list.
+
+ :param mappings: a sequence of dictionaries, each one containing the
+ state of the mapped row to be updated, in terms of the attribute names
+ on the mapped class. If the mapping refers to multiple tables, such
+ as a joined-inheritance mapping, each dictionary may contain keys
+ corresponding to all tables. All those keys which are present and
+ are not part of the primary key are applied to the SET clause of the
+ UPDATE statement; the primary key values, which are required, are
+ applied to the WHERE clause.
+
+
+ .. seealso::
+
+ :doc:`queryguide/dml`
+
+ :meth:`.Session.bulk_insert_mappings`
+
+ :meth:`.Session.bulk_save_objects`
+
+
+ """ # noqa: E501
+
+ return self._proxied.bulk_update_mappings(mapper, mappings)
+
+ def merge(
+ self,
+ instance: _O,
+ *,
+ load: bool = True,
+ options: Optional[Sequence[ORMOption]] = None,
+ ) -> _O:
+ r"""Copy the state of a given instance into a corresponding instance
+ within this :class:`.Session`.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ :meth:`.Session.merge` examines the primary key attributes of the
+ source instance, and attempts to reconcile it with an instance of the
+ same primary key in the session. If not found locally, it attempts
+ to load the object from the database based on primary key, and if
+ none can be located, creates a new instance. The state of each
+ attribute on the source instance is then copied to the target
+ instance. The resulting target instance is then returned by the
+ method; the original source instance is left unmodified, and
+ un-associated with the :class:`.Session` if not already.
+
+ This operation cascades to associated instances if the association is
+ mapped with ``cascade="merge"``.
+
+ See :ref:`unitofwork_merging` for a detailed discussion of merging.
+
+ :param instance: Instance to be merged.
+ :param load: Boolean, when False, :meth:`.merge` switches into
+ a "high performance" mode which causes it to forego emitting history
+ events as well as all database access. This flag is used for
+ cases such as transferring graphs of objects into a :class:`.Session`
+ from a second level cache, or to transfer just-loaded objects
+ into the :class:`.Session` owned by a worker thread or process
+ without re-querying the database.
+
+ The ``load=False`` use case adds the caveat that the given
+ object has to be in a "clean" state, that is, has no pending changes
+ to be flushed - even if the incoming object is detached from any
+ :class:`.Session`. This is so that when
+ the merge operation populates local attributes and
+ cascades to related objects and
+ collections, the values can be "stamped" onto the
+ target object as is, without generating any history or attribute
+ events, and without the need to reconcile the incoming data with
+ any existing related objects or collections that might not
+ be loaded. The resulting objects from ``load=False`` are always
+ produced as "clean", so it is only appropriate that the given objects
+ should be "clean" as well, else this suggests a mis-use of the
+ method.
+ :param options: optional sequence of loader options which will be
+ applied to the :meth:`_orm.Session.get` method when the merge
+ operation loads the existing version of the object from the database.
+
+ .. versionadded:: 1.4.24
+
+
+ .. seealso::
+
+ :func:`.make_transient_to_detached` - provides for an alternative
+ means of "merging" a single object into the :class:`.Session`
+
+
+ """ # noqa: E501
+
+ return self._proxied.merge(instance, load=load, options=options)
+
+ @overload
+ def query(self, _entity: _EntityType[_O]) -> Query[_O]: ...
+
+ @overload
+ def query(
+ self, _colexpr: TypedColumnsClauseRole[_T]
+ ) -> RowReturningQuery[Tuple[_T]]: ...
+
+ # START OVERLOADED FUNCTIONS self.query RowReturningQuery 2-8
+
+ # code within this block is **programmatically,
+ # statically generated** by tools/generate_tuple_map_overloads.py
+
+ @overload
+ def query(
+ self, __ent0: _TCCA[_T0], __ent1: _TCCA[_T1]
+ ) -> RowReturningQuery[Tuple[_T0, _T1]]: ...
+
+ @overload
+ def query(
+ self, __ent0: _TCCA[_T0], __ent1: _TCCA[_T1], __ent2: _TCCA[_T2]
+ ) -> RowReturningQuery[Tuple[_T0, _T1, _T2]]: ...
+
+ @overload
+ def query(
+ self,
+ __ent0: _TCCA[_T0],
+ __ent1: _TCCA[_T1],
+ __ent2: _TCCA[_T2],
+ __ent3: _TCCA[_T3],
+ ) -> RowReturningQuery[Tuple[_T0, _T1, _T2, _T3]]: ...
+
+ @overload
+ def query(
+ self,
+ __ent0: _TCCA[_T0],
+ __ent1: _TCCA[_T1],
+ __ent2: _TCCA[_T2],
+ __ent3: _TCCA[_T3],
+ __ent4: _TCCA[_T4],
+ ) -> RowReturningQuery[Tuple[_T0, _T1, _T2, _T3, _T4]]: ...
+
+ @overload
+ def query(
+ self,
+ __ent0: _TCCA[_T0],
+ __ent1: _TCCA[_T1],
+ __ent2: _TCCA[_T2],
+ __ent3: _TCCA[_T3],
+ __ent4: _TCCA[_T4],
+ __ent5: _TCCA[_T5],
+ ) -> RowReturningQuery[Tuple[_T0, _T1, _T2, _T3, _T4, _T5]]: ...
+
+ @overload
+ def query(
+ self,
+ __ent0: _TCCA[_T0],
+ __ent1: _TCCA[_T1],
+ __ent2: _TCCA[_T2],
+ __ent3: _TCCA[_T3],
+ __ent4: _TCCA[_T4],
+ __ent5: _TCCA[_T5],
+ __ent6: _TCCA[_T6],
+ ) -> RowReturningQuery[Tuple[_T0, _T1, _T2, _T3, _T4, _T5, _T6]]: ...
+
+ @overload
+ def query(
+ self,
+ __ent0: _TCCA[_T0],
+ __ent1: _TCCA[_T1],
+ __ent2: _TCCA[_T2],
+ __ent3: _TCCA[_T3],
+ __ent4: _TCCA[_T4],
+ __ent5: _TCCA[_T5],
+ __ent6: _TCCA[_T6],
+ __ent7: _TCCA[_T7],
+ ) -> RowReturningQuery[Tuple[_T0, _T1, _T2, _T3, _T4, _T5, _T6, _T7]]: ...
+
+ # END OVERLOADED FUNCTIONS self.query
+
+ @overload
+ def query(
+ self, *entities: _ColumnsClauseArgument[Any], **kwargs: Any
+ ) -> Query[Any]: ...
+
+ def query(
+ self, *entities: _ColumnsClauseArgument[Any], **kwargs: Any
+ ) -> Query[Any]:
+ r"""Return a new :class:`_query.Query` object corresponding to this
+ :class:`_orm.Session`.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Note that the :class:`_query.Query` object is legacy as of
+ SQLAlchemy 2.0; the :func:`_sql.select` construct is now used
+ to construct ORM queries.
+
+ .. seealso::
+
+ :ref:`unified_tutorial`
+
+ :ref:`queryguide_toplevel`
+
+ :ref:`query_api_toplevel` - legacy API doc
+
+
+ """ # noqa: E501
+
+ return self._proxied.query(*entities, **kwargs)
+
+ def refresh(
+ self,
+ instance: object,
+ attribute_names: Optional[Iterable[str]] = None,
+ with_for_update: ForUpdateParameter = None,
+ ) -> None:
+ r"""Expire and refresh attributes on the given instance.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ The selected attributes will first be expired as they would when using
+ :meth:`_orm.Session.expire`; then a SELECT statement will be issued to
+ the database to refresh column-oriented attributes with the current
+ value available in the current transaction.
+
+ :func:`_orm.relationship` oriented attributes will also be immediately
+ loaded if they were already eagerly loaded on the object, using the
+ same eager loading strategy that they were loaded with originally.
+
+ .. versionadded:: 1.4 - the :meth:`_orm.Session.refresh` method
+ can also refresh eagerly loaded attributes.
+
+ :func:`_orm.relationship` oriented attributes that would normally
+ load using the ``select`` (or "lazy") loader strategy will also
+ load **if they are named explicitly in the attribute_names
+ collection**, emitting a SELECT statement for the attribute using the
+ ``immediate`` loader strategy. If lazy-loaded relationships are not
+ named in :paramref:`_orm.Session.refresh.attribute_names`, then
+ they remain as "lazy loaded" attributes and are not implicitly
+ refreshed.
+
+ .. versionchanged:: 2.0.4 The :meth:`_orm.Session.refresh` method
+ will now refresh lazy-loaded :func:`_orm.relationship` oriented
+ attributes for those which are named explicitly in the
+ :paramref:`_orm.Session.refresh.attribute_names` collection.
+
+ .. tip::
+
+ While the :meth:`_orm.Session.refresh` method is capable of
+ refreshing both column and relationship oriented attributes, its
+ primary focus is on refreshing of local column-oriented attributes
+ on a single instance. For more open ended "refresh" functionality,
+ including the ability to refresh the attributes on many objects at
+ once while having explicit control over relationship loader
+ strategies, use the
+ :ref:`populate existing <orm_queryguide_populate_existing>` feature
+ instead.
+
+ Note that a highly isolated transaction will return the same values as
+ were previously read in that same transaction, regardless of changes
+ in database state outside of that transaction. Refreshing
+ attributes usually only makes sense at the start of a transaction
+ where database rows have not yet been accessed.
+
+ :param attribute_names: optional. An iterable collection of
+ string attribute names indicating a subset of attributes to
+ be refreshed.
+
+ :param with_for_update: optional boolean ``True`` indicating FOR UPDATE
+ should be used, or may be a dictionary containing flags to
+ indicate a more specific set of FOR UPDATE flags for the SELECT;
+ flags should match the parameters of
+ :meth:`_query.Query.with_for_update`.
+ Supersedes the :paramref:`.Session.refresh.lockmode` parameter.
+
+ .. seealso::
+
+ :ref:`session_expire` - introductory material
+
+ :meth:`.Session.expire`
+
+ :meth:`.Session.expire_all`
+
+ :ref:`orm_queryguide_populate_existing` - allows any ORM query
+ to refresh objects as they would be loaded normally.
+
+
+ """ # noqa: E501
+
+ return self._proxied.refresh(
+ instance,
+ attribute_names=attribute_names,
+ with_for_update=with_for_update,
+ )
+
+ def rollback(self) -> None:
+ r"""Rollback the current transaction in progress.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ If no transaction is in progress, this method is a pass-through.
+
+ The method always rolls back
+ the topmost database transaction, discarding any nested
+ transactions that may be in progress.
+
+ .. seealso::
+
+ :ref:`session_rollback`
+
+ :ref:`unitofwork_transaction`
+
+
+ """ # noqa: E501
+
+ return self._proxied.rollback()
+
+ @overload
+ def scalar(
+ self,
+ statement: TypedReturnsRows[Tuple[_T]],
+ params: Optional[_CoreSingleExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ **kw: Any,
+ ) -> Optional[_T]: ...
+
+ @overload
+ def scalar(
+ self,
+ statement: Executable,
+ params: Optional[_CoreSingleExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ **kw: Any,
+ ) -> Any: ...
+
+ def scalar(
+ self,
+ statement: Executable,
+ params: Optional[_CoreSingleExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ **kw: Any,
+ ) -> Any:
+ r"""Execute a statement and return a scalar result.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Usage and parameters are the same as that of
+ :meth:`_orm.Session.execute`; the return result is a scalar Python
+ value.
+
+
+ """ # noqa: E501
+
+ return self._proxied.scalar(
+ statement,
+ params=params,
+ execution_options=execution_options,
+ bind_arguments=bind_arguments,
+ **kw,
+ )
+
+ @overload
+ def scalars(
+ self,
+ statement: TypedReturnsRows[Tuple[_T]],
+ params: Optional[_CoreAnyExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ **kw: Any,
+ ) -> ScalarResult[_T]: ...
+
+ @overload
+ def scalars(
+ self,
+ statement: Executable,
+ params: Optional[_CoreAnyExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ **kw: Any,
+ ) -> ScalarResult[Any]: ...
+
+ def scalars(
+ self,
+ statement: Executable,
+ params: Optional[_CoreAnyExecuteParams] = None,
+ *,
+ execution_options: OrmExecuteOptionsParameter = util.EMPTY_DICT,
+ bind_arguments: Optional[_BindArguments] = None,
+ **kw: Any,
+ ) -> ScalarResult[Any]:
+ r"""Execute a statement and return the results as scalars.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ Usage and parameters are the same as that of
+ :meth:`_orm.Session.execute`; the return result is a
+ :class:`_result.ScalarResult` filtering object which
+ will return single elements rather than :class:`_row.Row` objects.
+
+ :return: a :class:`_result.ScalarResult` object
+
+ .. versionadded:: 1.4.24 Added :meth:`_orm.Session.scalars`
+
+ .. versionadded:: 1.4.26 Added :meth:`_orm.scoped_session.scalars`
+
+ .. seealso::
+
+ :ref:`orm_queryguide_select_orm_entities` - contrasts the behavior
+ of :meth:`_orm.Session.execute` to :meth:`_orm.Session.scalars`
+
+
+ """ # noqa: E501
+
+ return self._proxied.scalars(
+ statement,
+ params=params,
+ execution_options=execution_options,
+ bind_arguments=bind_arguments,
+ **kw,
+ )
+
+ @property
+ def bind(self) -> Optional[Union[Engine, Connection]]:
+ r"""Proxy for the :attr:`_orm.Session.bind` attribute
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ """ # noqa: E501
+
+ return self._proxied.bind
+
+ @bind.setter
+ def bind(self, attr: Optional[Union[Engine, Connection]]) -> None:
+ self._proxied.bind = attr
+
+ @property
+ def dirty(self) -> Any:
+ r"""The set of all persistent instances considered dirty.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ E.g.::
+
+ some_mapped_object in session.dirty
+
+ Instances are considered dirty when they were modified but not
+ deleted.
+
+ Note that this 'dirty' calculation is 'optimistic'; most
+ attribute-setting or collection modification operations will
+ mark an instance as 'dirty' and place it in this set, even if
+ there is no net change to the attribute's value. At flush
+ time, the value of each attribute is compared to its
+ previously saved value, and if there's no net change, no SQL
+ operation will occur (this is a more expensive operation so
+ it's only done at flush time).
+
+ To check if an instance has actionable net changes to its
+ attributes, use the :meth:`.Session.is_modified` method.
+
+
+ """ # noqa: E501
+
+ return self._proxied.dirty
+
+ @property
+ def deleted(self) -> Any:
+ r"""The set of all instances marked as 'deleted' within this ``Session``
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ """ # noqa: E501
+
+ return self._proxied.deleted
+
+ @property
+ def new(self) -> Any:
+ r"""The set of all instances marked as 'new' within this ``Session``.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ """ # noqa: E501
+
+ return self._proxied.new
+
+ @property
+ def identity_map(self) -> IdentityMap:
+ r"""Proxy for the :attr:`_orm.Session.identity_map` attribute
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ """ # noqa: E501
+
+ return self._proxied.identity_map
+
+ @identity_map.setter
+ def identity_map(self, attr: IdentityMap) -> None:
+ self._proxied.identity_map = attr
+
+ @property
+ def is_active(self) -> Any:
+ r"""True if this :class:`.Session` not in "partial rollback" state.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ .. versionchanged:: 1.4 The :class:`_orm.Session` no longer begins
+ a new transaction immediately, so this attribute will be False
+ when the :class:`_orm.Session` is first instantiated.
+
+ "partial rollback" state typically indicates that the flush process
+ of the :class:`_orm.Session` has failed, and that the
+ :meth:`_orm.Session.rollback` method must be emitted in order to
+ fully roll back the transaction.
+
+ If this :class:`_orm.Session` is not in a transaction at all, the
+ :class:`_orm.Session` will autobegin when it is first used, so in this
+ case :attr:`_orm.Session.is_active` will return True.
+
+ Otherwise, if this :class:`_orm.Session` is within a transaction,
+ and that transaction has not been rolled back internally, the
+ :attr:`_orm.Session.is_active` will also return True.
+
+ .. seealso::
+
+ :ref:`faq_session_rollback`
+
+ :meth:`_orm.Session.in_transaction`
+
+
+ """ # noqa: E501
+
+ return self._proxied.is_active
+
+ @property
+ def autoflush(self) -> bool:
+ r"""Proxy for the :attr:`_orm.Session.autoflush` attribute
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ """ # noqa: E501
+
+ return self._proxied.autoflush
+
+ @autoflush.setter
+ def autoflush(self, attr: bool) -> None:
+ self._proxied.autoflush = attr
+
+ @property
+ def no_autoflush(self) -> Any:
+ r"""Return a context manager that disables autoflush.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ e.g.::
+
+ with session.no_autoflush:
+
+ some_object = SomeClass()
+ session.add(some_object)
+ # won't autoflush
+ some_object.related_thing = session.query(SomeRelated).first()
+
+ Operations that proceed within the ``with:`` block
+ will not be subject to flushes occurring upon query
+ access. This is useful when initializing a series
+ of objects which involve existing database queries,
+ where the uncompleted object should not yet be flushed.
+
+
+ """ # noqa: E501
+
+ return self._proxied.no_autoflush
+
+ @property
+ def info(self) -> Any:
+ r"""A user-modifiable dictionary.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class
+ on behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ The initial value of this dictionary can be populated using the
+ ``info`` argument to the :class:`.Session` constructor or
+ :class:`.sessionmaker` constructor or factory methods. The dictionary
+ here is always local to this :class:`.Session` and can be modified
+ independently of all other :class:`.Session` objects.
+
+
+ """ # noqa: E501
+
+ return self._proxied.info
+
+ @classmethod
+ def close_all(cls) -> None:
+ r"""Close *all* sessions in memory.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ .. deprecated:: 1.3 The :meth:`.Session.close_all` method is deprecated and will be removed in a future release. Please refer to :func:`.session.close_all_sessions`.
+
+ """ # noqa: E501
+
+ return Session.close_all()
+
+ @classmethod
+ def object_session(cls, instance: object) -> Optional[Session]:
+ r"""Return the :class:`.Session` to which an object belongs.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ This is an alias of :func:`.object_session`.
+
+
+ """ # noqa: E501
+
+ return Session.object_session(instance)
+
+ @classmethod
+ def identity_key(
+ cls,
+ class_: Optional[Type[Any]] = None,
+ ident: Union[Any, Tuple[Any, ...]] = None,
+ *,
+ instance: Optional[Any] = None,
+ row: Optional[Union[Row[Any], RowMapping]] = None,
+ identity_token: Optional[Any] = None,
+ ) -> _IdentityKeyType[Any]:
+ r"""Return an identity key.
+
+ .. container:: class_bases
+
+ Proxied for the :class:`_orm.Session` class on
+ behalf of the :class:`_orm.scoping.scoped_session` class.
+
+ This is an alias of :func:`.util.identity_key`.
+
+
+ """ # noqa: E501
+
+ return Session.identity_key(
+ class_=class_,
+ ident=ident,
+ instance=instance,
+ row=row,
+ identity_token=identity_token,
+ )
+
+ # END PROXY METHODS scoped_session
+
+
+ScopedSession = scoped_session
+"""Old name for backwards compatibility."""