本文整理汇总了Python中sqlalchemy.orm.interfaces.SessionExtension方法的典型用法代码示例。如果您正苦于以下问题：Python interfaces.SessionExtension方法的具体用法？Python interfaces.SessionExtension怎么用？Python interfaces.SessionExtension使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类sqlalchemy.orm.interfaces的用法示例。
在下文中一共展示了interfaces.SessionExtension方法的4个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: before_insert
# 需要导入模块: from sqlalchemy.orm import interfaces [as 别名]
# 或者: from sqlalchemy.orm.interfaces import SessionExtension [as 别名]
def before_insert(self, mapper, connection, instance):
"""Receive an object instance before that instance is inserted
into its table.
This is a good place to set up primary key values and such
that aren't handled otherwise.
Column-based attributes can be modified within this method
which will result in the new value being inserted. However
*no* changes to the overall flush plan can be made, and
manipulation of the ``Session`` will not have the desired effect.
To manipulate the ``Session`` within an extension, use
``SessionExtension``.
The return value is only significant within the ``MapperExtension``
chain; the parent mapper's behavior isn't modified by this method.
"""
return EXT_CONTINUE 示例2: _adapt_listener
# 需要导入模块: from sqlalchemy.orm import interfaces [as 别名]
# 或者: from sqlalchemy.orm.interfaces import SessionExtension [as 别名]
def _adapt_listener(cls, self, listener):
for meth in [
'before_commit',
'after_commit',
'after_rollback',
'before_flush',
'after_flush',
'after_flush_postexec',
'after_begin',
'after_attach',
'after_bulk_update',
'after_bulk_delete',
]:
me_meth = getattr(SessionExtension, meth)
ls_meth = getattr(listener, meth)
if not util.methods_equivalent(me_meth, ls_meth):
event.listen(self, meth, getattr(listener, meth)) 示例3: before_update
# 需要导入模块: from sqlalchemy.orm import interfaces [as 别名]
# 或者: from sqlalchemy.orm.interfaces import SessionExtension [as 别名]
def before_update(self, mapper, connection, instance):
"""Receive an object instance before that instance is updated.
Note that this method is called for all instances that are marked as
"dirty", even those which have no net changes to their column-based
attributes. An object is marked as dirty when any of its column-based
attributes have a "set attribute" operation called or when any of its
collections are modified. If, at update time, no column-based
attributes have any net changes, no UPDATE statement will be issued.
This means that an instance being sent to before_update is *not* a
guarantee that an UPDATE statement will be issued (although you can
affect the outcome here).
To detect if the column-based attributes on the object have net
changes, and will therefore generate an UPDATE statement, use
``object_session(instance).is_modified(instance,
include_collections=False)``.
Column-based attributes can be modified within this method
which will result in the new value being updated. However
*no* changes to the overall flush plan can be made, and
manipulation of the ``Session`` will not have the desired effect.
To manipulate the ``Session`` within an extension, use
``SessionExtension``.
The return value is only significant within the ``MapperExtension``
chain; the parent mapper's behavior isn't modified by this method.
"""
return EXT_CONTINUE 示例4: before_delete
# 需要导入模块: from sqlalchemy.orm import interfaces [as 别名]
# 或者: from sqlalchemy.orm.interfaces import SessionExtension [as 别名]
def before_delete(self, mapper, connection, instance):
"""Receive an object instance before that instance is deleted.
Note that *no* changes to the overall flush plan can be made
here; and manipulation of the ``Session`` will not have the
desired effect. To manipulate the ``Session`` within an
extension, use ``SessionExtension``.
The return value is only significant within the ``MapperExtension``
chain; the parent mapper's behavior isn't modified by this method.
"""
return EXT_CONTINUE