defined bind parameter name that directly conflicts with
a column-named bind generated directly from the SET or
VALUES clause of an update/insert generates a compile error.
This reduces call counts and eliminates some cases where
undesirable name conflicts could still occur.
reimplementing the highest impact functions.
The actual speedups will depend heavily on your DBAPI and
the mix of datatypes used in your tables, and can vary from
a 50% improvement to more than 200%. It also provides a modest
(~20%) indirect improvement to ORM speed for large queries.
Note that it is *not* built/installed by default.
See README for installation instructions.
- The most common result processors conversion function were
moved to the new "processors" module. Dialect authors are
encouraged to use those functions whenever they correspond
to their needs instead of implementing custom ones.
API, used for any expression construct that can be sent to
execute(). FunctionElement now inherits Executable so that
it gains execution_options(), which are also propagated
to the select() that's generated within execute().
Executable in turn subclasses _Generative which marks
any ClauseElement that supports the @_generative
decorator - these may also become "public" for the benefit
of the compiler extension at some point.
of determining the return type from an expression
as well as the adaptation of the Python operator into
a SQL operator, based on the full left/right/operator
of the given expression. In particular
the date/time/interval system created for Postgresql
EXTRACT in [ticket:1647] has now been generalized into
the type system. The previous behavior which often
occured of an expression "column + literal" forcing
the type of "literal" to be the same as that of "column"
will now usually not occur - the type of
"literal" is first derived from the Python type of the
literal, assuming standard native Python types + date
types, before falling back to that of the known type
on the other side of the expression. Also part
of [ticket:1683].
same way any func.foo() construct is, with automatic
SELECT being applied when passed to execute().
- The "type" and "bind" keyword arguments of a func.foo()
construct are now local to "func." constructs and are
not part of the FunctionElement base class, allowing
a "type" to be handled in a custom constructor or
class-level variable.
to be compared to another set, typically with IN against
composite primary keys or similar. Also accepts an
IN with multiple columns. The "scalar select can
have only one column" error message is removed - will
rely upon the database to report problems with
col mismatch.
of statements have more consistent behavior w.r.t.
parenthesizing. Each compound element embedded within
another will now be grouped with parenthesis - previously,
the first compound element in the list would not be grouped,
as SQLite doesn't like a statement to start with
parenthesis. However, Postgresql in particular has
precedence rules regarding INTERSECT, and it is
more consistent for parenthesis to be applied equally
to all sub-elements. So now, the workaround for SQLite
is also what the workaround for PG was previously -
when nesting compound elements, the first one usually needs
".alias().select()" called on it to wrap it inside
of a subquery. [ticket:1665]
produces BLOB, BYTEA, or a similar "long binary" type.
New base BINARY and VARBINARY
types have been added to access these MySQL/MS-SQL specific
types in an agnostic way [ticket:1664].
Allows RowProxy objects to reference just the metadata they need and provides the "core" of ResultProxy
detached from the object itself, allowing ResultProxy implementations to vary more easily. will also
enable [ticket:1635]
only the DAY TO SECOND interval type so far due to lack
of support in cx_oracle for YEAR TO MONTH. [ticket:1467]
- The Interval type includes a "native" flag which controls
if native INTERVAL types (postgresql + oracle) are selected
if available, or not. "day_precision" and "second_precision"
arguments are also added which propagate as appropriately
to these native types. Related to [ticket:1467].
- DefaultDialect.type_descriptor moves back to being per-dialect.
TypeEngine/TypeDecorator key type impls to the dialect class
+ server_version_info so that the colspecs dict can be modified
per-dialect based on server version.
- Fixed TypeDecorator's incorrect usage of _impl_dict
configuring cx_oracle.UNICODE on OracleNVarChar. Attempts
were made to pass unicode data to/from a plain VARCHAR2 with
cx_oracle, both with and without setinputsizes in use, but
it doesn't appear to be possible - therefore users will need to use
Unicode/UnicodeText with oracle if data contains non-ASCII info.
[ticket:1517]
- updated the Unicode/UnicodeText docs to reflect this, that
convert_unicode might not be enough.
- allowed convert_unicode='force' to be significant for bind parameters
as well.
passed to the resulting statement. Currently only
Select-statements have these options, and the only option
used is "stream_results", and the only dialect which knows
"stream_results" is psycopg2.
- Query.yield_per() will set the "stream_results" statement
option automatically.
- Added "statement_options()" to Selects, which set statement
specific options. These enable e.g. dialect specific options
such as whether to enable using server side cursors, etc.
- The psycopg2 now respects the statement option
"stream_results". This option overrides the connection setting
"server_side_cursors". If true, server side cursors will be
used for the statement. If false, they will not be used, even
if "server_side_cursors" is true on the
connection. [ticket:1619]
- added a "frozendict" from http://code.activestate.com/recipes/414283/,
adding more default collections as immutable class vars on
Query, Insert, Select
correspondence for cloned selectables which contain
free-standing column expressions. This bug is
generally only noticeable when exercising newer
ORM behavior only availble in 0.6 via [ticket:1568],
but is more correct at the SQL expression level
as well. [ticket:1617]
before issuing the usual "expr != expr" clause. The
"expr != expr" can be very expensive, and it's preferred
that the user not issue in_() if the list is empty,
instead simply not querying, or modifying the criterion
as appropriate for more complex situations.
[ticket:1628]
"dbo.master", are now rendered in select() labels
with underscores for dots, i.e. "dbo_master_table_column".
This is a "friendly" label that behaves better
in result sets. [ticket:1428]
lazy load will fallback to the possibly cached query.get()
value, now works across join conditions where the two compared
types are not exactly the same class, but share the same
"affinity" - i.e. Integer and SmallInteger. Also allows
combinations of reflected and non-reflected types to work
with 0.5 style type reflection, such as PGText/Text (note 0.6
reflects types as their generic versions). [ticket:1556]
- types now support an "affinity comparison" operation, i.e.
that an Integer/SmallInteger are "compatible", or
a Text/String, PickleType/Binary, etc. Part of
[ticket:1556].
have native boolean support, will generate a CHECK
constraint "col IN (0, 1)" along with the int/smallint-
based column type. This can be switched off if
desired with create_constraint=False.
Note that MySQL has no native boolean *or* CHECK constraint
support so this feature isn't available on that platform.
[ticket:1589]
Uses a straight CheckConstraint with a generic expression. Preparing for boolean
constraint in [ticket:1589]
- CheckConstraint now accepts SQL expressions, though support for quoting of values
will be very limited. we don't want to get into formatting dates and such.
an error before passing to MySQL. Doesn't impact
CAST since VARCHAR is not allowed in MySQL CAST anyway,
the dialect renders CHAR/NCHAR in those cases.
[ticket:1252]
types to more intelligently determine float() vs. Decimal(),
[ticket:1567]
- since result processing is a hot issue of late, the DBAPI type
returned from cursor.description is certainly useful in cases like
these to determine an efficient result processor. There's likely
other result processors that can make use of it. But, backwards
incompat change to result_processor(). Happy major version number..
on all new connections, which allows all String/Text/etc.
types to skip the need to post-process bytestrings into
unicode (an expensive step due to its volume). Other
dialects which return unicode natively (pg8000, zxjdbc)
also skip unicode post-processing.
- String/Text/Unicode types now skip the unicode() check
on each result column value if the dialect has
detected the DBAPI as returning Python unicode objects
natively. This check is issued on first connect
using "SELECT CAST 'some text' AS VARCHAR(10)" or
equivalent, then checking if the returned object
is a Python unicode. This allows vast performance
increases for native-unicode DBAPIs, including
pysqlite/sqlite3, psycopg2, and pg8000.
method call counts when fetching columns that have no
type-level processing applied. Provides a 100% speed
improvement when fetching large result sets with no unicode
conversion. Many thanks to Elixir's Gaëtan de Menten
for this dramatic improvement ! [ticket:1586]
objects using names that match the keys of columns. These
bind parameters will circumvent the usual route to those
keys showing up in the VALUES or SET clause of the generated
SQL. [ticket:1579]
- deprecated PassiveDefault - use DefaultClause.
- the BINARY and MSBinary types now generate "BINARY" in all
cases. Omitting the "length" parameter will generate
"BINARY" with no length. Use BLOB to generate an unlengthed
binary column.
- the "quoting='quoted'" argument to MSEnum/ENUM is deprecated.
It's best to rely upon the automatic quoting.
- "shortname" attribute on bindparam() is removed.
- fold_equivalents flag on join is deprecated (will remain
until [ticket:1131] is implemented)
- "scalar" flag on select() is removed, use
select.as_scalar().
- 'transactional' flag on sessionmaker() and others is
removed. Use 'autocommit=True' to indicate 'transactional=False'.
- 'polymorphic_fetch' argument on mapper() is removed.
Loading can be controlled using the 'with_polymorphic'
option.
- 'select_table' argument on mapper() is removed. Use
'with_polymorphic=("*", <some selectable>)' for this
functionality.
- 'proxy' argument on synonym() is removed. This flag
did nothing throughout 0.5, as the "proxy generation"
behavior is now automatic.
- Passing a single list of elements to eagerload(),
eagerload_all(), contains_eager(), lazyload(),
defer(), and undefer() instead of multiple positional
-args is deprecated.
- Passing a single list of elements to query.order_by(),
query.group_by(), query.join(), or query.outerjoin()
instead of multiple positional *args is deprecated.
- query.iterate_instances() is removed. Use query.instances().
- Query.query_from_parent() is removed. Use the
sqlalchemy.orm.with_parent() function to produce a
"parent" clause, or alternatively query.with_parent().
- query._from_self() is removed, use query.from_self()
instead.
- the "comparator" argument to composite() is removed.
Use "comparator_factory".
- RelationProperty._get_join() is removed.
- the 'echo_uow' flag on Session is removed. Use
logging on the "sqlalchemy.orm.unitofwork" name.
- session.clear() is removed. use session.expunge_all().
- session.save(), session.update(), session.save_or_update()
are removed. Use session.add() and session.add_all().
- the "objects" flag on session.flush() remains deprecated.
- the "dont_load=True" flag on session.merge() is deprecated
in favor of "load=False".
- passing an InstanceState (internal SQLAlchemy state object) to
attributes.init_collection() or attributes.get_history() is
deprecated. These functions are public API and normally
expect a regular mapped object instance.
- the 'engine' parameter to declarative_base() is removed.
Use the 'bind' keyword argument.
sets require that all keys are present which are
present in the first bound parameter set. The structure
and behavior of an insert/update statement is very much
determined by the first parameter set, including which
defaults are going to fire off, and a minimum of
guesswork is performed with all the rest so that performance
is not impacted. For this reason defaults would otherwise
silently "fail" for missing parameters, so this is now guarded
against. [ticket:1566]
of this object has been simplified and moved into
ExecutionContext. Dialects which support sequences should
add a `fire_sequence()` method to their execution context
implementation. [ticket:1566]
Mike Bayer