SQLAlchemy 0.7.9 Released

[Michael Bayer]

SQLAlchemy 0.7.9 is released. This is a maintenance release primarily containing bug fixes applied to both the 0.7 and 0.8 SQLAlchemy series.

0.7.9 includes some adjustments that will also be present in 0.8, including changes to the event-dispatch system which dramatically reduce the amount of memory used. There are also several fixes related to the relatively new common table expression (CTE) construct.

Other fixes include small bugs present in components such as the ORM, SQL generation system, and various dialect-specific bugs. 0.7.9 also has updates to its unit test system which were backported from 0.8.

The 0.8 series, which includes a long list of new features and improvements, is more or less ready for initial beta releases, and will be available for download within the coming weeks.

Download SQLAlchemy 0.7.9 at: http://www.sqlalchemy.org/download.html

0.7.9
=====
- orm
- [bug] Fixed bug mostly local to new
AbstractConcreteBase helper where the "type"
attribute from the superclass would not
be overridden on the subclass to produce the
"reserved for base" error message, instead placing
a do-nothing attribute there. This was inconsistent
vs. using ConcreteBase as well as all the behavior
of classical concrete mappings, where the "type"
column from the polymorphic base would be explicitly
disabled on subclasses, unless overridden
explicitly.

- [bug] A warning is emitted when lazy='dynamic'
is combined with uselist=False. This is an
exception raise in 0.8.

- [bug] Fixed bug whereby user error in related-object
assignment could cause recursion overflow if the
assignment triggered a backref of the same name
as a bi-directional attribute on the incorrect
class to the same target. An informative
error is raised now.

- [bug] Fixed bug where incorrect type information
would be passed when the ORM would bind the
"version" column, when using the "version" feature.
Tests courtesy Daniel Miller. [ticket:2539]

- [bug] Extra logic has been added to the "flush"
that occurs within Session.commit(), such that the
extra state added by an after_flush() or
after_flush_postexec() hook is also flushed in a
subsequent flush, before the "commit" completes.
Subsequent calls to flush() will continue until
the after_flush hooks stop adding new state.
An "overflow" counter of 100 is also in place,
in the event of a broken after_flush() hook
adding new content each time. [ticket:2566]

- sql
- [bug] Fixed the DropIndex construct to support
an Index associated with a Table in a remote
schema. [ticket:2571]

- [bug] Fixed bug in over() construct whereby
passing an empty list for either partition_by
or order_by, as opposed to None, would fail
to generate correctly.
Courtesy Gunnlaugur Þór Briem.
[ticket:2574]

- [bug] Fixed CTE bug whereby positional
bound parameters present in the CTEs themselves
would corrupt the overall ordering of
bound parameters. This primarily
affected SQL Server as the platform with
positional binds + CTE support.
[ticket:2521]

- [bug] Fixed more un-intuitivenesses in CTEs
which prevented referring to a CTE in a union
of itself without it being aliased.
CTEs now render uniquely
on name, rendering the outermost CTE of a given
name only - all other references are rendered
just as the name. This even includes other
CTE/SELECTs that refer to different versions
of the same CTE object, such as a SELECT
or a UNION ALL of that SELECT. We are
somewhat loosening the usual link between object
identity and lexical identity in this case.
A true name conflict between two unrelated
CTEs now raises an error.

- [bug] quoting is applied to the column names
inside the WITH RECURSIVE clause of a
common table expression according to the
quoting rules for the originating Column.
[ticket:2512]

- [bug] Fixed regression introduced in 0.7.6
whereby the FROM list of a SELECT statement
could be incorrect in certain "clone+replace"
scenarios. [ticket:2518]

- [bug] Fixed bug whereby usage of a UNION
or similar inside of an embedded subquery
would interfere with result-column targeting,
in the case that a result-column had the same
ultimate name as a name inside the embedded
UNION. [ticket:2552]

- [bug] Fixed a regression since 0.6 regarding
result-row targeting. It should be possible
to use a select() statement with string
based columns in it, that is
select(['id', 'name']).select_from('mytable'),
and have this statement be targetable by
Column objects with those names; this is the
mechanism by which
query(MyClass).from_statement(some_statement)
works. At some point the specific case of
using select(['id']), which is equivalent to
select([literal_column('id')]), stopped working
here, so this has been re-instated and of
course tested. [ticket:2558]

- [bug] Added missing operators is_(), isnot()
to the ColumnOperators base, so that these long-available
operators are present as methods like all
the other operators. [ticket:2544]

- engine
- [bug] Fixed bug whereby
a disconnect detect + dispose that occurs
when the QueuePool has threads waiting
for connections would leave those
threads waiting for the duration of
the timeout on the old pool (or indefinitely
if timeout was disabled). The fix
now notifies those waiters with a special
exception case and has them move onto
the new pool. [ticket:2522]

- [feature] Dramatic improvement in memory
usage of the event system; instance-level
collections are no longer created for a
particular type of event until
instance-level listeners are established
for that event. [ticket:2516]

- [bug] Added gaerdbms import to mysql/__init__.py,
the absense of which was preventing the new
GAE dialect from being loaded. [ticket:2529]

- [bug] Fixed cextension bug whereby the
"ambiguous column error" would fail to
function properly if the given index were
a Column object and not a string.
Note there are still some column-targeting
issues here which are fixed in 0.8.
[ticket:2553]

- [bug] Fixed the repr() of Enum to include
the "name" and "native_enum" flags. Helps
Alembic autogenerate.

- sqlite
- [bug] Adjusted a very old bugfix which attempted
to work around a SQLite issue that itself was
"fixed" as of sqlite 3.6.14, regarding quotes
surrounding a table name when using
the "foreign_key_list" pragma. The fix has been
adjusted to not interfere with quotes that
are *actually in the name* of a column or table,
to as much a degree as possible; sqlite still
doesn't return the correct result for foreign_key_list()
if the target table actually has quotes surrounding
its name, as *part* of its name (i.e. """mytable""").
[ticket:2568]

- [bug] Adjusted column default reflection code to
convert non-string values to string, to accommodate
old SQLite versions that don't deliver
default info as a string. [ticket:2265]

- [feature] Added support for the localtimestamp()
SQL function implemented in SQLite, courtesy
Richard Mitchell.

- postgresql
- [bug] Columns in reflected primary key constraint
are now returned in the order in which the constraint
itself defines them, rather than how the table
orders them. Courtesy Gunnlaugur Þór Briem.
[ticket:2531].

- [bug] Added 'terminating connection' to the list
of messages we use to detect a disconnect with PG, which
appears to be present in some versions when the server
is restarted. [ticket:2570]

- mysql
- [bug] Updated mysqlconnector interface to use
updated "client flag" and "charset" APIs,
courtesy David McNelis.

- mssql
- [bug] Fixed compiler bug whereby using a correlated
subquery within an ORDER BY would fail to render correctly
if the stament also used LIMIT/OFFSET, due to mis-rendering
within the ROW_NUMBER() OVER clause. Fix courtesy
sayap [ticket:2538]

- [bug] Fixed compiler bug whereby a given
select() would be modified if it had an "offset"
attribute, causing the construct to not compile
correctly a second time. [ticket:2545]

- [bug] Fixed bug where reflection of primary key constraint
would double up columns if the same constraint/table
existed in multiple schemas.