specific to mapper inheritance - tweak Proxy property to give the proxied descriptor a chance to raise an exception - have Concrete prop raise on all access, not just trying to use it in a query. This might be a little problematic backwards compatible-wise, however - adjust mapper and relationship to more correctly allow for concreteinheritedprop to be overridden, in the case of backrefs etc., some cases were still raising due to how props are set up - work assert_raises/assert_raises_message to be expressed via a context manager that can be used directly
:func:`.attributes.flag_modified` where the change event would not be propagated if the attribute had been reassigned to itself. fixes #2997
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]
didn't match. use straight memoized_props here for now, add a perf test to check it
to descriptors, like hybrids, synonyms, composites, user-defined descriptors, etc. The attribute adaptation which goes on has been made more robust, such that if a descriptor returns another instrumented attribute, rather than a compound SQL expression element, the operation will still proceed. Addtionally, the "adapted" operator will retain its class; previously, a change in class from ``InstrumentedAttribute`` to ``QueryableAttribute`` (a superclass) would interact with Python's operator system such that an expression like ``aliased(MyClass.x) > MyClass.x`` would reverse itself to read ``myclass.x < myclass_1.x``. The adapted attribute will also refer to the new :class:`.AliasedClass` as its parent which was not always the case before. [ticket:2872]
attribute history from being written on behalf of the target attribute. This has the effect of the object not being written to the Session.dirty list if it is mutated. Previously, the object would be present in Session.dirty, but no change would take place on behalf of the modified attribute during flush. The attribute still emits events such as backref events and user-defined events and will still receive mutations from backrefs. [ticket:2833]
attribute will now honor the "passive" flag passed to it; as this defaults to ``PASSIVE_OFF``, the function will by default query the database if the value is not present. This is a behavioral change vs. 0.8. [ticket:2787] - Added new method :meth:`.AttributeState.load_history`, works like :attr:`.AttributeState.history` but also fires loader callables.
of groups of column expressions to a :class:`.Query` construct. The group of columns are returned as a single tuple by default. The behavior of :class:`.Bundle` can be overridden however to provide any sort of result processing to the returned row. One example included is :attr:`.Composite.Comparator.bundle`, which applies a bundled form of a "composite" mapped attribute. [ticket:2824] - The :func:`.composite` construct now maintains the return object when used in a column-oriented :class:`.Query`, rather than expanding out into individual columns. This makes use of the new :class:`.Bundle` feature internally. This behavior is backwards incompatible; to select from a composite column which will expand out, use ``MyClass.some_composite.clauses``.
- rework the event system so that event modules load after their targets, dependencies are reversed - create an improved strategy lookup system for the ORM - rework the ORM to have very few import cycles - move out "importlater" to just util.dependency - other tricks to cross-populate modules in as clear a way as possible