set to a SQL expression for an UPDATE, and the SQL expression when
compared to the previous value of the attribute would produce a SQL
comparison other than ``==`` or ``!=``, the exception "Boolean value
of this clause is not defined" would raise.   The fix ensures that
the unit of work will not interpret the SQL expression in this way.
fixes #3402

Output in the error message the table name and the column name.

Output in the error message the table name and the column name.

into more performant executemany() call, similarly to how INSERT
statements can be batched; this will be invoked within flush
to the degree that subsequent UPDATE statements for the
same mapping and table involve the identical columns within the
VALUES clause, as well as that no VALUES-level SQL expressions
are embedded.
- some other inlinings within persistence.py

mapper is implicitly combining one of its column-based attributes
with that of the parent, where those columns normally don't necessarily
share the same value.  This is an extension of an existing check that
was added via :ticket:`1892`; however this new check emits only a
warning, instead of an exception, to allow for applications that may
be relying upon the existing behavior.
fixes #3042

Found using: https://github.com/intgr/topy

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

is currently being supported in addition to nose, and will likely
be preferred to nose going forward.   The nose plugin system used
by SQLAlchemy has been split out so that it works under pytest as
well.  There are no plans to drop support for nose at the moment
and we hope that the test suite itself can continue to remain as
agnostic of testing platform as possible.  See the file
README.unittests.rst for updated information on running tests
with pytest.

The test plugin system has also been enhanced to support running
tests against mutiple database URLs at once, by specifying the ``--db``
and/or ``--dburi`` flags multiple times.  This does not run the entire test
suite for each database, but instead allows test cases that are specific
to certain backends make use of that backend as the test is run.
When using pytest as the test runner, the system will also run
specific test suites multiple times, once for each database, particularly
those tests within the "dialect suite".   The plan is that the enhanced
system will also be used by Alembic, and allow Alembic to run
migration operation tests against multiple backends in one run, including
third-party backends not included within Alembic itself.
Third party dialects and extensions are also encouraged to standardize
on SQLAlchemy's test suite as a basis; see the file README.dialects.rst
for background on building out from SQLAlchemy's test platform.