Sqlalchemy

:released: November 3, 2017

.. change::
:tags: bug, sqlite
:tickets: 4099
:versions: 1.2.0b3

Fixed bug where SQLite CHECK constraint reflection would fail
if the referenced table were in a remote schema, e.g. on SQLite a
remote database referred to by ATTACH.

.. change::
:tags: bug, mysql
:tickets: 4097
:versions: 1.2.0b3

Warning emitted when MariaDB 10.2.8 or earlier in the 10.2
series is detected as there are major issues with CHECK
constraints within these versions that were resolved as of
10.2.9.

Note that this changelog message was NOT released with
SQLAlchemy 1.2.0b3 and was added retroactively.

.. change::
:tags: bug, mssql
:tickets: 4095
:versions: 1.2.0b3

Added a full range of "connection closed" exception codes to the
PyODBC dialect for SQL Server, including '08S01', '01002', '08003',
'08007', '08S02', '08001', 'HYT00', 'HY010'. Previously, only '08S01'
was covered.

.. change::
:tags: bug, sql
:tickets: 4126
:versions: 1.2.0

Fixed bug where ``__repr__`` of :class:`.ColumnDefault` would fail
if the argument were a tuple. Pull request courtesy Nicolas Caniart.

.. change::
:tags: bug, orm, declarative
:tickets: 4124
:versions: 1.2.0

Fixed a bug where a descriptor, which is a mapped column or a
relationship elsewhere in a hierarchy based on
:class:`.AbstractConcreteBase`, would be referenced during a refresh
operation, leading to an error since the attribute is not mapped as a
mapper property. A similar issue can arise for other attributes
like the "type" column added by :class:`.AbstractConcreteBase` if the
class fails to include "concrete=True" in its mapper, however the check
here should also prevent that scenario from causing a problem.

.. change:: 4006
:tags: bug, postgresql
:tickets: 4006
:versions: 1.2.0b3

Made further fixes to the :class:`_types.ARRAY` class in conjunction with
COLLATE, as the fix made in :ticket:`4006` failed to accommodate
for a multidimensional array.

.. change::
:tags: bug, orm, ext
:tickets: 4116
:versions: 1.2.0

Fixed bug where the association proxy would inadvertently link itself
to an :class:`.AliasedClass` object if it were called first with
the :class:`.AliasedClass` as a parent, causing errors upon subsequent
usage.

.. change::
:tags: bug, mysql
:tickets: 4120
:versions: 1.2.0

MySQL 5.7.20 now warns for use of the tx_isolation variable; a version
check is now performed and uses transaction_isolation instead
to prevent this warning.

.. change::
:tags: bug, postgresql
:tickets: 4107
:versions: 1.2.0b3

Fixed bug in :obj:`_functions.array_agg` function where passing an argument
that is already of type :class:`_types.ARRAY`, such as a PostgreSQL
:obj:`_postgresql.array` construct, would produce a ``ValueError``, due
to the function attempting to nest the arrays.

.. change::
:tags: bug, orm
:tickets: 4078
:versions: 1.2.0b3

Fixed bug where ORM relationship would warn against conflicting sync
targets (e.g. two relationships would both write to the same column) for
sibling classes in an inheritance hierarchy, where the two relationships
would never actually conflict during writes.

.. change::
:tags: bug, postgresql
:tickets: 4074
:versions: 1.2.0b3

Fixed bug in PostgreSQL :meth:`.postgresql.dml.Insert.on_conflict_do_update`
which would prevent the insert statement from being used as a CTE,
e.g. via :meth:`_expression.Insert.cte`, within another statement.

.. change::
:tags: bug, orm
:tickets: 4103
:versions: 1.2.0b3

Fixed bug where correlated select used against single-table inheritance
entity would fail to render correctly in the outer query, due to adjustment
for single inheritance discriminator criteria inappropriately re-applying
the criteria to the outer query.

.. change::
:tags: bug, mysql
:tickets: 4096
:versions: 1.2.0b3

Fixed issue where CURRENT_TIMESTAMP would not reflect correctly
in the MariaDB 10.2 series due to a syntax change, where the function
is now represented as ``current_timestamp()``.

.. change::
:tags: bug, mysql
:tickets: 4098
:versions: 1.2.0b3

MariaDB 10.2 now supports CHECK constraints (warning: use version 10.2.9
or greater due to upstream issues noted in :ticket:`4097`). Reflection
now takes these CHECK constraints into account when they are present in
the ``SHOW CREATE TABLE`` output.

.. change::
:tags: bug, sql
:tickets: 4093
:versions: 1.2.0b3

Fixed bug where the recently added :meth:`.ColumnOperators.any_`
and :meth:`.ColumnOperators.all_` methods didn't work when called
as methods, as opposed to using the standalone functions
:func:`_expression.any_` and :func:`_expression.all_`. Also
added documentation examples for these relatively unintuitive
SQL operators.

.. changelog::

:released: September 5, 2017

.. change::
:tags: bug, orm
:tickets: 4069
:versions: 1.2.0b3

Fixed bug in :meth:`.Session.merge` following along similar lines as that
of :ticket:`4030`, where an internal check for a target object in
the identity map could lead to an error if it were to be garbage collected
immediately before the merge routine actually retrieves the object.

.. change::
:tags: bug, orm
:tickets: 4048
:versions: 1.2.0b3

Fixed bug where an :func:`.undefer_group` option would not be recognized
if it extended from a relationship that was loading using joined eager
loading. Additionally, as the bug led to excess work being performed,
Python function call counts are also improved by 20% within the initial
calculation of result set columns, complementing the joined eager load
improvements of :ticket:`3915`.

.. change::
:tags: bug, orm
:tickets: 4068

Fixed race condition in ORM identity map which would cause objects
to be inappropriately removed during a load operation, causing
duplicate object identities to occur, particularly under joined eager
loading which involves deduplication of objects. The issue is specific
to garbage collection of weak references and is observed only under the
PyPy interpreter.

.. change::
:tags: bug, orm
:tickets: 4056
:versions: 1.2.0b3

Fixed bug in :meth:`.Session.merge` where objects in a collection that had
the primary key attribute set to ``None`` for a key that is typically
autoincrementing would be considered to be a database-persisted key for
part of the internal deduplication process, causing only one object to
actually be inserted in the database.

.. change::
:tags: bug, sql
:tickets: 4053

Altered the range specification for window functions to allow
for two of the same PRECEDING or FOLLOWING keywords in a range
by allowing for the left side of the range to be positive
and for the right to be negative, e.g. (1, 3) is
"1 FOLLOWING AND 3 FOLLOWING".

.. change::
:tags: bug, orm
:tickets: 4067
:versions: 1.2.0b3

An :class:`.InvalidRequestError` is raised when a :func:`.synonym`
is used against an attribute that is not against a :class:`.MapperProperty`,
such as an association proxy. Previously, a recursion overflow would
occur trying to locate non-existent attributes.

.. changelog::

:released: August 3, 2017

.. changelog::

:released: July 24, 2017

.. change:: cache_order_sequence
:tags: feature, oracle, postgresql
:versions: 1.2.0b1

Added new keywords :paramref:`.Sequence.cache` and
:paramref:`.Sequence.order` to :class:`.Sequence`, to allow rendering
of the CACHE parameter understood by Oracle and PostgreSQL, and the
ORDER parameter understood by Oracle. Pull request
courtesy David Moore.


.. change:: 4033
:tags: bug, orm
:tickets: 4033
:versions: 1.2.0b2

Fixed regression from 1.1.11 where adding additional non-entity
columns to a query that includes an entity with subqueryload
relationships would fail, due to an inspection added in 1.1.11 as a
result of :ticket:`4011`.


.. change:: 4031
:tags: bug, orm
:versions: 1.2.0b2
:tickets: 4031

Fixed bug involving JSON NULL evaluation logic added in 1.1 as part
of :ticket:`3514` where the logic would not accommodate ORM
mapped attributes named differently from the :class:`_schema.Column`
that was mapped.

.. change:: 4030
:tags: bug, orm
:versions: 1.2.0b2
:tickets: 4030

Added ``KeyError`` checks to all methods within
:class:`.WeakInstanceDict` where a check for ``key in dict`` is
followed by indexed access to that key, to guard against a race against
garbage collection that under load can remove the key from the dict
after the code assumes its present, leading to very infrequent
``KeyError`` raises.

.. changelog::

:released: Monday, June 19, 2017

.. change:: 4012
:tags: bug, sql
:tickets: 4012
:versions: 1.2.0b1

Fixed AttributeError which would occur in :class:`.WithinGroup`
construct during an iteration of the structure.

.. change:: 4011
:tags: bug, orm
:tickets: 4011
:versions: 1.2.0b1

Fixed issue with subquery eagerloading which continues on from
the series of issues fixed in :ticket:`2699`, :ticket:`3106`,
:ticket:`3893` involving that the "subquery" contains the correct
FROM clause when beginning from a joined inheritance subclass
and then subquery eager loading onto a relationship from
the base class, while the query also includes criteria against
the subclass. The fix in the previous tickets did not accommodate
for additional subqueryload operations loading more deeply from
the first level, so the fix has been further generalized.

.. change:: 4005
:tags: bug, postgresql
:tickets: 4005
:versions: 1.2.0b1

Continuing with the fix that correctly handles PostgreSQL
version string "10devel" released in 1.1.8, an additional regexp
bump to handle version strings of the form "10beta1". While
PostgreSQL now offers better ways to get this information, we
are sticking w/ the regexp at least through 1.1.x for the least
amount of risk to compatibility w/ older or alternate PostgreSQL
databases.

.. change:: 4006
:tags: bug, postgresql
:tickets: 4006
:versions: 1.2.0b1

Fixed bug where using :class:`_types.ARRAY` with a string type that
features a collation would fail to produce the correct syntax
within CREATE TABLE.

.. change:: 4007
:tags: bug, mysql
:tickets: 4007
:versions: 1.2.0b1

MySQL 5.7 has introduced permission limiting for the "SHOW VARIABLES"
command; the MySQL dialect will now handle when SHOW returns no
row, in particular for the initial fetch of SQL_MODE, and will
emit a warning that user permissions should be modified to allow the
row to be present.

.. change:: 3994
:tags: bug, mssql
:tickets: 3994
:versions: 1.2.0b1

Fixed bug where SQL Server transaction isolation must be fetched
from a different view when using Azure data warehouse, the query
is now attempted against both views and then a NotImplemented
is raised unconditionally if failure continues to provide the
best resiliency against future arbitrary API changes in new
SQL Server versions.

.. change:: 3997
:tags: bug, oracle
:tickets: 3997
:versions: 1.2.0b1

Support for two-phase transactions has been removed entirely for
cx_Oracle when version 6.0b1 or later of the DBAPI is in use. The two-
phase feature historically has never been usable under cx_Oracle 5.x in
any case, and cx_Oracle 6.x has removed the connection-level "twophase"
flag upon which this feature relied.

.. change:: 3973
:tags: bug, mssql
:tickets: 3973
:versions: 1.2.0b1

Added a placeholder type :class:`_mssql.XML` to the SQL Server
dialect, so that a reflected table which includes this type can
be re-rendered as a CREATE TABLE. The type has no special round-trip
behavior nor does it currently support additional qualifying
arguments.

.. changelog::

:released: Friday, May 19, 2017

.. change:: 3986
:tags: bug, orm
:versions: 1.2.0b1
:tickets: 3986

Fixed bug where a cascade such as "delete-orphan" (but others as well)
would fail to locate an object linked to a relationship that itself
is local to a subclass in an inheritance relationship, thus causing
the operation to not take place.

.. change:: 3975
:tags: bug, oracle
:versions: 1.2.0b1
:tickets: 3975

Fixed bug in cx_Oracle dialect where version string parsing would
fail for cx_Oracle version 6.0b1 due to the "b" character. Version
string parsing is now via a regexp rather than a simple split.

.. change:: 3949
:tags: bug, schema
:versions: 1.2.0b1
:tickets: 3949

An :class:`.ArgumentError` is now raised if a
:class:`_schema.ForeignKeyConstraint` object is created with a mismatched
number of "local" and "remote" columns, which otherwise causes the
internal state of the constraint to be incorrect. Note that this
also impacts the condition where a dialect's reflection process
produces a mismatched set of columns for a foreign key constraint.

.. change:: 3980
:tags: bug, ext
:versions: 1.2.0b1
:tickets: 3980

Protected against testing "None" as a class in the case where
declarative classes are being garbage collected and new
automap prepare() operations are taking place concurrently, very
infrequently hitting a weakref that has not been fully acted upon
after gc.

.. change::
:tags: bug, postgresql
:versions: 1.2.0b1

Added "autocommit" support for GRANT, REVOKE keywords. Pull request
courtesy Jacob Hayes.

.. change:: 3966
:tags: bug, mysql
:versions: 1.2.0b1
:tickets: 3966

Removed an ancient and unnecessary intercept of the UTC_TIMESTAMP
MySQL function, which was getting in the way of using it with a
parameter.

.. change:: 3961
:tags: bug, mysql
:versions: 1.2.0b1
:tickets: 3961

Fixed bug in MySQL dialect regarding rendering of table options in
conjunction with PARTITION options when rendering CREATE TABLE.
The PARTITION related options need to follow the table options,
whereas previously this ordering was not enforced.


.. changelog::