def _index_query(self, obj):
"""
Returns the query needed for fetching the index of this record relative
to version history.
"""
alias = sa.orm.aliased(obj)
subquery = (
sa.select([sa.func.count('1')], from_obj=[alias.__table__])
.where(
getattr(alias, tx_column_name(obj))
<
getattr(obj, tx_column_name(obj))
)
.correlate(alias.__table__)
.label('position')
)
query = (
sa.select([subquery], from_obj=[obj.__table__])
.where(
sa.and_(
*map(eq, zip(identity(obj.__class__), identity(obj)))
)
)
.order_by(
getattr(obj.__class__, tx_column_name(obj))
)
)
return query
def get_or_create_version_object(self, target):
"""
Return version object for given parent object. If no version object
exists for given parent object, create one.
:param target: Parent object to create the version object for
"""
version_cls = version_class(target.__class__)
version_id = identity(target) + (self.current_transaction.id, )
version_key = (version_cls, version_id)
if version_key not in self.version_objs:
version_obj = version_cls()
self.version_objs[version_key] = version_obj
self.version_session.add(version_obj)
tx_column = self.manager.option(
target,
'transaction_column_name'
)
setattr(
version_obj,
tx_column,
self.current_transaction.id
)
return version_obj
else:
return self.version_objs[version_key]
def get_or_create_version_object(self, target):
"""
Return version object for given parent object. If no version object
exists for given parent object, create one.
:param target: Parent object to create the version object for
"""
version_cls = version_class(target.__class__)
version_id = identity(target) + (self.current_transaction.id, )
version_key = (version_cls, version_id)
if version_key not in self.version_objs:
version_obj = version_cls()
self.version_objs[version_key] = version_obj
self.version_session.add(version_obj)
tx_column = self.manager.option(
target,
'transaction_column_name'
)
setattr(
version_obj,
tx_column,
self.current_transaction.id
)
return version_obj
else:
return self.version_objs[version_key]
def format_key(self, target):
# We cannot use target._sa_instance_state.identity here since object's
# identity is not yet updated at this phase
return (target.__class__, identity(target))
def format_key(self, target):
# We cannot use target._sa_instance_state.identity here since object's
# identity is not yet updated at this phase
return (target.__class__, identity(target))