Sqlalchemy

: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::

:released: April 4, 2017

.. change:: 3956
:tags: bug, ext
:tickets: 3956

Fixed regression released in 1.1.8 due to :ticket:`3950` where the
deeper search for information about column types in the case of a
"schema type" or a :class:`.TypeDecorator` would produce an attribute
error if the mapping also contained a :obj:`.column_property`.

.. change:: 3952
:tags: bug, sql
:versions: 1.2.0b1
:tickets: 3952

Fixed regression released in 1.1.5 due to :ticket:`3859` where
adjustments to the "right-hand-side" evaluation of an expression
based on :class:`.Variant` to honor the underlying type's
"right-hand-side" rules caused the :class:`.Variant` type
to be inappropriately lost, in those cases when we *do* want the
left-hand side type to be transferred directly to the right hand side
so that bind-level rules can be applied to the expression's argument.

.. change:: 3955
:tags: bug, sql, postgresql
:versions: 1.2.0b1
:tickets: 3955

Changed the mechanics of :class:`_engine.ResultProxy` to unconditionally
delay the "autoclose" step until the :class:`_engine.Connection` is done
with the object; in the case where PostgreSQL ON CONFLICT with
RETURNING returns no rows, autoclose was occurring in this previously
non-existent use case, causing the usual autocommit behavior that
occurs unconditionally upon INSERT/UPDATE/DELETE to fail.

.. changelog::

:released: March 31, 2017

.. change:: 3950
:tags: bug, ext
:versions: 1.2.0b1
:tickets: 3950

Fixed bug in :mod:`sqlalchemy.ext.mutable` where the
:meth:`.Mutable.as_mutable` method would not track a type that had
been copied using :meth:`.TypeEngine.copy`. This became more of
a regression in 1.1 compared to 1.0 because the :class:`.TypeDecorator`
class is now a subclass of :class:`.SchemaEventTarget`, which among
other things indicates to the parent :class:`_schema.Column` that the type
should be copied when the :class:`_schema.Column` is. These copies are
common when using declarative with mixins or abstract classes.

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

Added support for bound parameters, e.g. those normally set up
via :meth:`_query.Query.params`, to the :meth:`.baked.Result.count`
method. Previously, support for parameters were omitted. Pull request
courtesy Pat Deegan.

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

Added support for parsing the PostgreSQL version string for
a development version like "PostgreSQL 10devel". Pull request
courtesy Sean McCully.

.. changelog::