mirror of
https://github.com/sqlalchemy/sqlalchemy.git
synced 2026-05-28 03:26:01 -04:00
Mike Bayer
58fab1be98
- add the other versioning examples from the wiki - modernize the dictlike examples
60 lines
1.6 KiB
Python
60 lines
1.6 KiB
Python
"""
|
|
Illustrates an extension which creates version tables for entities and stores
|
|
records for each change. The given extensions generate an anonymous "history" class which
|
|
represents historical versions of the target object.
|
|
|
|
Usage is illustrated via a unit test module ``test_versioning.py``, which can
|
|
be run via nose::
|
|
|
|
cd examples/versioning
|
|
nosetests -v
|
|
|
|
A fragment of example usage, using declarative::
|
|
|
|
from history_meta import Versioned, versioned_session
|
|
|
|
Base = declarative_base()
|
|
|
|
class SomeClass(Versioned, Base):
|
|
__tablename__ = 'sometable'
|
|
|
|
id = Column(Integer, primary_key=True)
|
|
name = Column(String(50))
|
|
|
|
def __eq__(self, other):
|
|
assert type(other) is SomeClass and other.id == self.id
|
|
|
|
Session = sessionmaker(bind=engine)
|
|
versioned_session(Session)
|
|
|
|
sess = Session()
|
|
sc = SomeClass(name='sc1')
|
|
sess.add(sc)
|
|
sess.commit()
|
|
|
|
sc.name = 'sc1modified'
|
|
sess.commit()
|
|
|
|
assert sc.version == 2
|
|
|
|
SomeClassHistory = SomeClass.__history_mapper__.class_
|
|
|
|
assert sess.query(SomeClassHistory).\\
|
|
filter(SomeClassHistory.version == 1).\\
|
|
all() \\
|
|
== [SomeClassHistory(version=1, name='sc1')]
|
|
|
|
The ``Versioned`` mixin is designed to work with declarative. To use
|
|
the extension with classical mappers, the ``_history_mapper`` function
|
|
can be applied::
|
|
|
|
from history_meta import _history_mapper
|
|
|
|
m = mapper(SomeClass, sometable)
|
|
_history_mapper(m)
|
|
|
|
SomeHistoryClass = SomeClass.__history_mapper__.class_
|
|
|
|
.. autosource::
|
|
|
|
""" |