all cases, so that MySQL 5.6.6 with the
``explicit_defaults_for_timestamp`` flag enabled will
will allow TIMESTAMP to continue to work as expected when
``nullable=False``.  Existing applications are unaffected as
SQLAlchemy has always emitted NULL for a TIMESTAMP column that
is ``nullable=True``.  fixes #3155

:meth:`.Connection.invalidate` method, or an invalidation due
to a database disconnect, would fail if the
``isolation_level`` parameter had been used with
:meth:`.Connection.execution_options`; the "finalizer" that resets
the isolation level would be called on the no longer opened connection.
fixes #3302

with :meth:`.Connection.execution_options` when a :class:`.Transaction`
is in play; DBAPIs and/or SQLAlchemy dialects such as psycopg2,
MySQLdb may implicitly rollback or commit the transaction, or
not change the setting til next transaction, so this is never safe.
- Added new parameter :paramref:`.Session.connection.execution_options`
which may be used to set up execution options on a :class:`.Connection`
when it is first checked out, before the transaction has begun.
This is used to set up options such as isolation level on the
connection before the transaction starts.
- added new documentation section
detailing best practices for setting transaction isolation with
sessions.
fixes #3296

primaryjoin that referred to the same "local" column multiple
times in the "column that points to itself" style of self-referential
join would not be substituted in all cases.   The logic to determine
substitutions here has been reworked to be more open-ended.
fixes #3300

the ARRAY type when using psycopg2.  The psycopg2 dialect now
employs use of the psycopg2.extras.register_uuid() hook
so that UUID values are always passed to/from the DBAPI as
UUID() objects.   The :paramref:`.UUID.as_uuid` flag is still
honored, except with psycopg2 we need to convert returned
UUID objects back into strings when this is disabled.
fixes #2940

using psycopg2 2.5.4 or greater, which features native conversion
of JSONB data so that SQLAlchemy's converters must be disabled;
additionally, the newly added psycopg2 extension
``extras.register_default_jsonb`` is used to establish a JSON
deserializer passed to the dialect via the ``json_deserializer``
argument.  Also repaired the Postgresql integration tests which
weren't actually round-tripping the JSONB type as opposed to the
JSON type.  Pull request courtesy Mateusz Susik.

- Repaired the use of the "array_oid" flag when registering the
HSTORE type with older psycopg2 versions < 2.4.3, which does not
support this flag, as well as use of the native json serializer
hook "register_default_json" with user-defined ``json_deserializer``
on psycopg2 versions < 2.5, which does not include native json.

conventions that include the token ``%(column_0_name)s``; the
constraint expression is scanned for columns.  Additionally,
naming conventions for check constraints that don't include the
``%(constraint_name)s`` token will now work for :class:`.SchemaType`-
generated constraints, such as those of :class:`.Boolean` and
:class:`.Enum`; this stopped working in 0.9.7 due to :ticket:`3067`.
fixes #3299

the logic used to link a :class:`.ForeignKey` to its parent could fail
when the foreign key used "link_to_name=True" in conjunction with
a target :class:`.Table` that would not receive its parent column until
later, such as within a reflection + "useexisting" scenario,
if the target column in fact had a key value different from its name,
as would occur in reflection if column reflect events were used to
alter the .key of reflected :class:`.Column` objects so that the
link_to_name becomes significant.  Also repaired support for column
type via FK transmission in a similar way when target columns had a
different key and were referenced using link_to_name.
fixes #3298