ultimately will populate a foreign key column in conflict with
another, where the relationships are attempting to copy values
from different source columns.  This occurs in the case where
composite foreign keys with overlapping columns are mapped to
relationships that each refer to a different referenced column.
A new documentation section illustrates the example as well as how
to overcome the issue by specifying "foreign" columns specifically
on a per-relationship basis.
fixes #3230

and parameters are not displayed if None, reducing confusion for
error messages that weren't related to a statement.  The full
module and classname for the DBAPI-level exception is displayed,
making it clear that this is a wrapped DBAPI exception.  The
statement and parameters themselves are bounded within a bracketed
sections to better isolate them from the error message and from
each other.
fixes #3172

names in the given dictionary of values into mapped attribute names
against the mapped class being updated.  Previously, string names
were taken in directly and passed to the core update statement without
any means to resolve against the mapped entity.  Support for synonyms
and hybrid attributes as the subject attributes of
:meth:`.Query.update` are also supported.
fixes #3228

- pep8

"binds" (e.g. engines to use), such engines can be associated with
mixin classes, concrete subclasses, as well as a wider variety
of table metadata such as joined inheritance tables.
fixes #3035

ORM functions that are derived as "public factory" symbols, which
should assist with documentation tools being able to report on the
target module.
fixes #3218