to disable autoflush, in the case that the attribute needs to lazy-load
the "old" value, as in when replacing one-to-one values or some
kinds of many-to-one. A flush at this point otherwise occurs
at the point that the attribute is None and can cause NULL violations.
[ticket:2921]
- The system of loader options has been entirely rearchitected to build
upon a much more comprehensive base, the :class:`.Load` object. This
base allows any common loader option like :func:`.joinedload`,
:func:`.defer`, etc. to be used in a "chained" style for the purpose
of specifying options down a path, such as ``joinedload("foo").subqueryload("bar")``.
The new system supersedes the usage of dot-separated path names,
multiple attributes within options, and the usage of ``_all()`` options.
- Added a new load option :func:`.orm.load_only`. This allows a series
of column names to be specified as loading "only" those attributes,
deferring the rest.
construct after it's been constructed already. This is not
a pattern for normal use but we like to change the setting
for demonstration purposes in tutorials.
an "orphan" has been modified to more closely match the
behavior as that of persistent objects, which is that the object
is expunged from the :class:`.Session` as soon as it is
de-associated from any of its orphan-enabled parents. Previously,
the pending object would be expunged only if de-associated
from all of its orphan-enabled parents. The new flag ``legacy_is_orphan``
is added to :func:`.orm.mapper` which re-establishes the
legacy behavior. [ticket:2655]
become an externally usable package but still remains within the main sqlalchemy parent package.
in this system, we use kind of an ugly hack to get the noseplugin imported outside of the
"sqlalchemy" package, while still making it available within sqlalchemy for usage by
third party libraries.
now generates attribute events. Previously, a None
append would be ignored in some cases. Related
to [ticket:2229].
- [feature] The presence of None in a mapped collection
now raises an error during flush. Previously,
None values in collections would be silently ignored.
[ticket:2229]
delete-orphan cascade with one-to-many
or many-to-many without single-parent=True
is now an error. The ORM
would fail to function subsequent to this
warning in any case. [ticket:2405]
delete-orphan without delete to no longer
refer to 0.6, as we never got around to
upgrading this to an exception. Ideally
this might be better as an exception but
it's not critical either way. [ticket:2325]
- add new test suite to test_cascades for cascade
arguments
against an object which contained None in a
collection would raise an internal exception.
Reverted this to 0.6's behavior which is to
accept the None but obviously nothing is
persisted. Ideally, collections with None
present or on append() should at least emit a
warning, which is being considered for 0.8.
[ticket:2205]
self-referential relationships - this since
SQLA 0.7 no longer enforces "parent with no
child" at the ORM level; this check is left
up to foreign key nullability.
Related to [ticket:1912]
- a lot of cleanup and refactoring on relationship()
init, clarification
condition of being asked to UPDATE or DELETE
on a primary key value that contains NULL
in it. [ticket:2127]
- Some refinements to attribute history. More
changes are pending possibly in 0.8, but
for now history has been modified such that
scalar history doesn't have a "side effect"
of populating None for a non-present value.
This allows a slightly better ability to
distinguish between a None set and no actual
change, affects [ticket:2127] as well.
- rewriting the history tests in test_attributes to be
individual per operation/assertion. its a huge job
so this is partial for the moment.
all referncing tests to not use globals
- tests that deal with pickle specifically load the fixture classes
from test.lib.pickleable, which gets some more classes added
- removed weird sa05 pickling tests that don't matter
access to the cls/self.tables/classes registries
- express orm/_base.py ORMTest in terms of engine/_base.py TablesTest,
factor out common steps into TablesTest, remove AltEngineTest as a
separate class. will further consolidate these base classes
outside of "sqlalchemy" and under "test/".
Rationale:
- coverage plugin works without issue, without need for an awkward
additional package install
- command line for "nosetests" isn't polluted with SQLAlchemy options
[ticket:1949]
It's now possible to issue INSERT for an object that would otherwise
be an orphan due to no parent object specified, along a relationship
that specifies "delete-orphan" cascade. The detection of this condition
as an error should now be accomplished via NOT NULL foreign keys.
[ticket:1912]
when "save-update" cascade is disabled, or the target object is otherwise not
present in the session, and collection/scalar changes have taken place. A warning
is emitted describing the type of operation, the target reference, and the relationship
description, stating that the operation will not take place. The operation then doesn't
take place. [ticket:1973]
- clean up test_cascade a little bit, remove cruft
- docs about backref cascade
- Another new flag on relationship(), cascade_backrefs,
disables the "save-update" cascade when the event was
initiated on the "reverse" side of a bidirectional
relationship. This is a cleaner behavior so that
many-to-ones can be set on a transient object without
it getting sucked into the child object's session,
while still allowing the forward collection to
cascade. We *might* default this to False in 0.7.
- one-to-many relationships now maintain a list of positive
parent-child associations within the flush, preventing
previous parents marked as deleted from cascading a
delete or NULL foreign key set on those child objects,
despite the end-user not removing the child from the old
association. [ticket:1764]
- re-established Preprocess as unique on their arguments,
as they were definitely duped in inheritance scenarios
- added a "memo" feature to UOWTransaction which represents the usual
pattern of using the .attributes collection
- added the test case from [ticket:1081] into perf/
relationship(), to eliminate confusion over the relational
algebra term. relation() however will remain available
in equal capacity for the foreseeable future. [ticket:1740]
values from a scalar or collection attribute into the new session
during an add() operation. This so that the flush() operation
will also delete or modify rows of those disconnected items.
Julien Castets