of work such that loading for related many-to-one objects is slightly more aggressive, in the case of a graph of self-referential objects that are to be deleted; the load of related objects is to help determine the correct order for deletion if passive_deletes is not set. - revert the changes to test_delete_unloaded_m2o, these deletes do in fact need to occur in the order of the two child objects first.
that might take one of multiple directions; apply this to test_delete_unloaded_m2o which is now illustrating multiple paths due to #3060/#3061, though still doing the right thing.
scenario, where an INSERT/DELETE can be turned into an UPDATE. In this situation, a many-to-one relationship set to None, or in some cases a scalar attribute set to None, may not be detected as a net change in value, and therefore the UPDATE would not reset what was on the previous row. This is due to some as-yet unresovled side effects of the way attribute history works in terms of implicitly assuming None isn't really a "change" for a previously un-set attribute. See also :ticket:`3061`. fixes #3060
to True, indicates that a series of DELETE statements should confirm that the cursor rowcount matches the number of primary keys that should have matched; this behavior had been taken off in most cases (except when version_id is used) to support the unusual edge case of self-referential ON DELETE CASCADE; to accomodate this, the message is now just a warning, not an exception, and the flag can be used to indicate a mapping that expects self-refererntial cascaded deletes of this nature. See also :ticket:`2403` for background on the original change. re: #2403 fix #3007
where one is to be deleted from ON DELETE CASCADE succeeds; the check here makes that fail. We will need to add an option to enable/disable this check per mapping, will likely do this in next version
it for DELETE would fail to target the correct row for DELETE. Then to compound matters, basic "number of rows matched" checks were not being performed. Both issues are fixed, however note that the "rows matched" check requires so-called "sane multi-row count" functionality; the DBAPI's executemany() method must count up the rows matched by individual statements and SQLAlchemy's dialect must mark this feature as supported, currently applies to some mysql dialects, psycopg2, sqlite only. fixes #3006 - Enabled "sane multi-row count" checking for the psycopg2 DBAPI, as this seems to be supported as of psycopg2 2.0.9.
- went through examples/ and cleaned out excess list() calls
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.
such as before_flush(), before_update(), etc. will now function as they would within non-event code, regarding consideration of the PK/FK values used in the lazy-emitted query. Previously, special flags would be established that would cause lazy loads to load related items based on the "previous" value of the parent PK/FK values specifically when called upon within a flush; the signal to load in this way is now localized to where the unit of work actually needs to load that way. Note that the UOW does sometimes load these collections before the before_update() event is called, so the usage of "passive_updates" or not can affect whether or not a collection will represent the "old" or "new" data, when accessed within a flush event, based on when the lazy load was emitted. The change is backwards incompatible in the exceedingly small chance that user event code depended on the old behavior. [ticket:2350]