:released: Wed Feb 03 2010
.. change::
:tags: release, major
:tickets:
For the full set of feature descriptions, see
https://docs.sqlalchemy.org/en/latest/changelog/migration_06.html .
This document is a work in progress.
.. change::
:tags: release, major
:tickets:
All bug fixes and feature enhancements from the most
recent 0.5 version and below are also included within 0.6.
.. change::
:tags: release, major
:tickets:
Platforms targeted now include Python 2.4/2.5/2.6, Python
3.1, Jython2.5.
.. change::
:tags: orm
:tickets:
Changes to query.update() and query.delete():
- the 'expire' option on query.update() has been renamed to
'fetch', thus matching that of query.delete().
'expire' is deprecated and issues a warning.
- query.update() and query.delete() both default to
'evaluate' for the synchronize strategy.
- the 'synchronize' strategy for update() and delete()
raises an error on failure. There is no implicit fallback
onto "fetch". Failure of evaluation is based on the
structure of criteria, so success/failure is deterministic
based on code structure.
.. change::
:tags: orm
:tickets: 1186, 1492, 1544
Enhancements on many-to-one relations:
- many-to-one relations now fire off a lazyload in fewer
cases, including in most cases will not fetch the "old"
value when a new one is replaced.
- many-to-one relation to a joined-table subclass now uses
get() for a simple load (known as the "use_get"
condition), i.e. Related->Sub(Base), without the need to
redefine the primaryjoin condition in terms of the base
table.
- specifying a foreign key with a declarative column, i.e.
ForeignKey(MyRelatedClass.id) doesn't break the "use_get"
condition from taking place
- relation(), eagerload(), and eagerload_all() now feature
an option called "innerjoin". Specify `True` or `False` to
control whether an eager join is constructed as an INNER
or OUTER join. Default is `False` as always. The mapper
options will override whichever setting is specified on
relation(). Should generally be set for many-to-one, not
nullable foreign key relations to allow improved join
performance.
- the behavior of eagerloading such that the main query is
wrapped in a subquery when LIMIT/OFFSET are present now
makes an exception for the case when all eager loads are
many-to-one joins. In those cases, the eager joins are
against the parent table directly along with the
limit/offset without the extra overhead of a subquery,
since a many-to-one join does not add rows to the result.
.. change::
:tags: orm
:tickets:
Enhancements / Changes on Session.merge():
.. change::
:tags: orm
:tickets:
the "dont_load=True" flag on Session.merge() is deprecated
and is now "load=False".
.. change::
:tags: orm
:tickets:
Session.merge() is performance optimized, using half the
call counts for "load=False" mode compared to 0.5 and
significantly fewer SQL queries in the case of collections
for "load=True" mode.
.. change::
:tags: orm
:tickets:
merge() will not issue a needless merge of attributes if the
given instance is the same instance which is already present.
.. change::
:tags: orm
:tickets:
merge() now also merges the "options" associated with a given
state, i.e. those passed through query.options() which follow
along with an instance, such as options to eagerly- or
lazyily- load various attributes. This is essential for
the construction of highly integrated caching schemes. This
is a subtle behavioral change vs. 0.5.
.. change::
:tags: orm
:tickets:
A bug was fixed regarding the serialization of the "loader
path" present on an instance's state, which is also necessary
when combining the usage of merge() with serialized state
and associated options that should be preserved.
.. change::
:tags: orm
:tickets:
The all new merge() is showcased in a new comprehensive
example of how to integrate Beaker with SQLAlchemy. See
the notes in the "examples" note below.
.. change::
:tags: orm
:tickets: 1362
Primary key values can now be changed on a joined-table inheritance
object, and ON UPDATE CASCADE will be taken into account when
the flush happens. Set the new "passive_updates" flag to False
on mapper() when using SQLite or MySQL/MyISAM.
.. change::
:tags: orm
:tickets: 1671
flush() now detects when a primary key column was updated by
an ON UPDATE CASCADE operation from another primary key, and
can then locate the row for a subsequent UPDATE on the new PK
value. This occurs when a relation() is there to establish
the relationship as well as passive_updates=True.
.. change::
:tags: orm
:tickets:
the "save-update" cascade will now cascade the pending *removed*
values from a scalar or collection attribute into the new session
during an add() operation. This so that the flush() operation
will also delete or modify rows of those disconnected items.
.. change::
:tags: orm
:tickets: 1531
Using a "dynamic" loader with a "secondary" table now produces
a query where the "secondary" table is *not* aliased. This
allows the secondary Table object to be used in the "order_by"
attribute of the relation(), and also allows it to be used
in filter criterion against the dynamic relation.
.. change::
:tags: orm
:tickets: 1643
relation() with uselist=False will emit a warning when
an eager or lazy load locates more than one valid value for
the row. This may be due to primaryjoin/secondaryjoin
conditions which aren't appropriate for an eager LEFT OUTER
JOIN or for other conditions.
.. change::
:tags: orm
:tickets: 1633
an explicit check occurs when a synonym() is used with
map_column=True, when a ColumnProperty (deferred or otherwise)
exists separately in the properties dictionary sent to mapper
with the same keyname. Instead of silently replacing
the existing property (and possible options on that property),
an error is raised.
.. change::
:tags: orm
:tickets:
a "dynamic" loader sets up its query criterion at construction
time so that the actual query is returned from non-cloning
accessors like "statement".
.. change::
:tags: orm
:tickets:
the "named tuple" objects returned when iterating a
Query() are now pickleable.
.. change::
:tags: orm
:tickets: 1542
mapping to a select() construct now requires that you
make an alias() out of it distinctly. This to eliminate
confusion over such issues as
.. change::
:tags: orm
:tickets: 1537
query.join() has been reworked to provide more consistent
behavior and more flexibility (includes)
.. change::
:tags: orm
:tickets:
query.select_from() accepts multiple clauses to produce
multiple comma separated entries within the FROM clause.
Useful when selecting from multiple-homed join() clauses.
.. change::
:tags: orm
:tickets:
query.select_from() also accepts mapped classes, aliased()
constructs, and mappers as arguments. In particular this
helps when querying from multiple joined-table classes to ensure
the full join gets rendered.
.. change::
:tags: orm
:tickets: 1135
query.get() can be used with a mapping to an outer join
where one or more of the primary key values are None.
.. change::
:tags: orm
:tickets: 1568
query.from_self(), query.union(), others which do a
"SELECT * from (SELECT...)" type of nesting will do
a better job translating column expressions within the subquery
to the columns clause of the outer query. This is
potentially backwards incompatible with 0.5, in that this
may break queries with literal expressions that do not have labels
applied (i.e. literal('foo'), etc.)
.. change::
:tags: orm
:tickets: 1622
relation primaryjoin and secondaryjoin now check that they
are column-expressions, not just clause elements. this prohibits
things like FROM expressions being placed there directly.
.. change::
:tags: orm
:tickets: 1415
`expression.null()` is fully understood the same way
None is when comparing an object/collection-referencing
attribute within query.filter(), filter_by(), etc.
.. change::
:tags: orm
:tickets: 1052
added "make_transient()" helper function which transforms a
persistent/ detached instance into a transient one (i.e.
deletes the instance_key and removes from any session.)
.. change::
:tags: orm
:tickets: 1339
the allow_null_pks flag on mapper() is deprecated, and
the feature is turned "on" by default. This means that
a row which has a non-null value for any of its primary key
columns will be considered an identity. The need for this
scenario typically only occurs when mapping to an outer join.
.. change::
:tags: orm
:tickets:
the mechanics of "backref" have been fully merged into the
finer grained "back_populates" system, and take place entirely
within the _generate_backref() method of RelationProperty. This
makes the initialization procedure of RelationProperty
simpler and allows easier propagation of settings (such as from
subclasses of RelationProperty) into the reverse reference.
The internal BackRef() is gone and backref() returns a plain
tuple that is understood by RelationProperty.
.. change::
:tags: orm
:tickets: 1569
The version_id_col feature on mapper() will raise a warning when
used with dialects that don't support "rowcount" adequately.
.. change::
:tags: orm
:tickets:
added "execution_options()" to Query, to so options can be
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.
.. change::
:tags: orm
:tickets:
Query.yield_per() will set the "stream_results" statement
option automatically.
.. change::
:tags: orm
:tickets:
Deprecated or removed:
* 'allow_null_pks' flag on mapper() is deprecated. It does
nothing now and the setting is "on" in all cases.
* '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".
* ScopedSession.mapper remains deprecated. See the
usage recipe at
https://www.sqlalchemy.org/trac/wiki/UsageRecipes/SessionAwareMapper
* 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.
.. change::
:tags: sql
:tickets:
the "autocommit" flag on select() and text() as well
as select().autocommit() are deprecated - now call
.execution_options(autocommit=True) on either of those
constructs, also available directly on Connection and orm.Query.
.. change::
:tags: sql
:tickets:
the autoincrement flag on column now indicates the column
which should be linked to cursor.lastrowid, if that method
is used. See the API docs for details.
.. change::
:tags: sql
:tickets: 1566
an executemany() now requires that all bound parameter
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.
.. change::
:tags: sql
:tickets:
returning() support is native to insert(), update(),
delete(). Implementations of varying levels of
functionality exist for PostgreSQL, Firebird, MSSQL and
Oracle. returning() can be called explicitly with column
expressions which are then returned in the resultset,
usually via fetchone() or first().
insert() constructs will also use RETURNING implicitly to
get newly generated primary key values, if the database
version in use supports it (a version number check is
performed). This occurs if no end-user returning() was
specified.
.. change::
:tags: sql
:tickets: 1665
union(), intersect(), except() and other "compound" types
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.
.. change::
:tags: sql
:tickets: 1579
insert() and update() constructs can now embed bindparam()
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.
.. change::
:tags: sql
:tickets: 1524
the Binary type now returns data as a Python string
(or a "bytes" type in Python 3), instead of the built-
in "buffer" type. This allows symmetric round trips
of binary data.
.. change::
:tags: sql
:tickets:
Added a tuple_() construct, allows sets of expressions
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.
.. change::
:tags: sql
:tickets:
User-defined "default" and "onupdate" callables which
accept a context should now call upon
"context.current_parameters" to get at the dictionary
of bind parameters currently being processed. This
dict is available in the same way regardless of
single-execute or executemany-style statement execution.
.. change::
:tags: sql
:tickets: 1428
multi-part schema names, i.e. with dots such as
"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.
.. change::
:tags: sql
:tickets:
removed needless "counter" behavior with select()
labelnames that match a column name in the table,
i.e. generates "tablename_id" for "id", instead of
"tablename_id_1" in an attempt to avoid naming
conflicts, when the table has a column actually
named "tablename_id" - this is because
the labeling logic is always applied to all columns
so a naming conflict will never occur.
.. change::
:tags: sql
:tickets: 1628
calling expr.in_([]), i.e. with an empty list, emits a warning
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.
.. change::
:tags: sql
:tickets:
Added "execution_options()" to select()/text(), which set the
default options for the Connection. See the note in "engines".
.. change::
:tags: sql
:tickets: 1131
Deprecated or removed:
* "scalar" flag on select() is removed, use
select.as_scalar().
* "shortname" attribute on bindparam() is removed.
* postgres_returning, firebird_returning flags on
insert(), update(), delete() are deprecated, use
the new returning() method.
* fold_equivalents flag on join is deprecated (will remain
until is implemented)
.. change::
:tags: engines
:tickets: 443
transaction isolation level may be specified with
create_engine(... isolation_level="..."); available on
postgresql and sqlite.
.. change::
:tags: engines
:tickets:
Connection has execution_options(), generative method
which accepts keywords that affect how the statement
is executed w.r.t. the DBAPI. Currently supports
"stream_results", causes psycopg2 to use a server
side cursor for that statement, as well as
"autocommit", which is the new location for the "autocommit"
option from select() and text(). select() and
text() also have .execution_options() as well as
ORM Query().
.. change::
:tags: engines
:tickets: 1630
fixed the import for entrypoint-driven dialects to
not rely upon silly tb_info trick to determine import
error status.
.. change::
:tags: engines
:tickets:
added first() method to ResultProxy, returns first row and
closes result set immediately.
.. change::
:tags: engines
:tickets:
RowProxy objects are now pickleable, i.e. the object returned
by result.fetchone(), result.fetchall() etc.
.. change::
:tags: engines
:tickets:
RowProxy no longer has a close() method, as the row no longer
maintains a reference to the parent. Call close() on
the parent ResultProxy instead, or use autoclose.
.. change::
:tags: engines
:tickets: 1586
ResultProxy internals have been overhauled to greatly reduce
method call counts when fetching columns. Can provide a large
speed improvement (up to more than 100%) when fetching large
result sets. The improvement is larger when fetching columns
that have no type-level processing applied and when using
results as tuples (instead of as dictionaries). Many
thanks to Elixir's Gaëtan de Menten for this dramatic
improvement !
.. change::
:tags: engines
:tickets:
Databases which rely upon postfetch of "last inserted id"
to get at a generated sequence value (i.e. MySQL, MS-SQL)
now work correctly when there is a composite primary key
where the "autoincrement" column is not the first primary
key column in the table.
.. change::
:tags: engines
:tickets:
the last_inserted_ids() method has been renamed to the
descriptor "inserted_primary_key".
.. change::
:tags: engines
:tickets: 1554
setting echo=False on create_engine() now sets the loglevel
to WARN instead of NOTSET. This so that logging can be
disabled for a particular engine even if logging
for "sqlalchemy.engine" is enabled overall. Note that the
default setting of "echo" is `None`.
.. change::
:tags: engines
:tickets:
ConnectionProxy now has wrapper methods for all transaction
lifecycle events, including begin(), rollback(), commit()
begin_nested(), begin_prepared(), prepare(), release_savepoint(),
etc.
.. change::
:tags: engines
:tickets:
Connection pool logging now uses both INFO and DEBUG
log levels for logging. INFO is for major events such
as invalidated connections, DEBUG for all the acquire/return
logging. `echo_pool` can be False, None, True or "debug"
the same way as `echo` works.
.. change::
:tags: engines
:tickets: 1621
All pyodbc-dialects now support extra pyodbc-specific
kw arguments 'ansi', 'unicode_results', 'autocommit'.
.. change::
:tags: engines
:tickets:
the "threadlocal" engine has been rewritten and simplified
and now supports SAVEPOINT operations.
.. change::
:tags: engines
:tickets:
deprecated or removed
* result.last_inserted_ids() is deprecated. Use
result.inserted_primary_key
* dialect.get_default_schema_name(connection) is now
public via dialect.default_schema_name.
* the "connection" argument from engine.transaction() and
engine.run_callable() is removed - Connection itself
now has those methods. All four methods accept
\*args and \**kwargs which are passed to the given callable,
as well as the operating connection.
.. change::
:tags: schema
:tickets: 1541
the `__contains__()` method of `MetaData` now accepts
strings or `Table` objects as arguments. If given
a `Table`, the argument is converted to `table.key` first,
i.e. "[schemaname.]<tablename>"
.. change::
:tags: schema
:tickets:
deprecated MetaData.connect() and
ThreadLocalMetaData.connect() have been removed - send
the "bind" attribute to bind a metadata.
.. change::
:tags: schema
:tickets:
deprecated metadata.table_iterator() method removed (use
sorted_tables)
.. change::
:tags: schema
:tickets:
deprecated PassiveDefault - use DefaultClause.
.. change::
:tags: schema
:tickets:
the "metadata" argument is removed from DefaultGenerator
and subclasses, but remains locally present on Sequence,
which is a standalone construct in DDL.
.. change::
:tags: schema
:tickets:
Removed public mutability from Index and Constraint
objects:
* ForeignKeyConstraint.append_element()
* Index.append_column()
* UniqueConstraint.append_column()
* PrimaryKeyConstraint.add()
* PrimaryKeyConstraint.remove()
These should be constructed declaratively (i.e. in one
construction).
.. change::
:tags: schema
:tickets: 1545
The "start" and "increment" attributes on Sequence now
generate "START WITH" and "INCREMENT BY" by default,
on Oracle and PostgreSQL. Firebird doesn't support
these keywords right now.
.. change::
:tags: schema
:tickets:
UniqueConstraint, Index, PrimaryKeyConstraint all accept
lists of column names or column objects as arguments.
.. change::
:tags: schema
:tickets:
Other removed things:
- Table.key (no idea what this was for)
- Table.primary_key is not assignable - use
table.append_constraint(PrimaryKeyConstraint(...))
- Column.bind (get via column.table.bind)
- Column.metadata (get via column.table.metadata)
- Column.sequence (use column.default)
- ForeignKey(constraint=some_parent) (is now private _constraint)
.. change::
:tags: schema
:tickets:
The use_alter flag on ForeignKey is now a shortcut option
for operations that can be hand-constructed using the
DDL() event system. A side effect of this refactor is
that ForeignKeyConstraint objects with use_alter=True
will *not* be emitted on SQLite, which does not support
ALTER for foreign keys.
.. change::
:tags: schema
:tickets: 1605
ForeignKey and ForeignKeyConstraint objects now correctly
copy() all their public keyword arguments.
.. change::
:tags: reflection/inspection
:tickets:
Table reflection has been expanded and generalized into
a new API called "sqlalchemy.engine.reflection.Inspector".
The Inspector object provides fine-grained information about
a wide variety of schema information, with room for expansion,
including table names, column names, view definitions, sequences,
indexes, etc.
.. change::
:tags: reflection/inspection
:tickets:
Views are now reflectable as ordinary Table objects. The same
Table constructor is used, with the caveat that "effective"
primary and foreign key constraints aren't part of the reflection
results; these have to be specified explicitly if desired.
.. change::
:tags: reflection/inspection
:tickets:
The existing autoload=True system now uses Inspector underneath
so that each dialect need only return "raw" data about tables
and other objects - Inspector is the single place that information
is compiled into Table objects so that consistency is at a maximum.
.. change::
:tags: ddl
:tickets:
the DDL system has been greatly expanded. the DDL() class
now extends the more generic DDLElement(), which forms the basis
of many new constructs:
- CreateTable()
- DropTable()
- AddConstraint()
- DropConstraint()
- CreateIndex()
- DropIndex()
- CreateSequence()
- DropSequence()
These support "on" and "execute-at()" just like plain DDL()
does. User-defined DDLElement subclasses can be created and
linked to a compiler using the sqlalchemy.ext.compiler extension.
.. change::
:tags: ddl
:tickets:
The signature of the "on" callable passed to DDL() and
DDLElement() is revised as follows:
ddl
the DDLElement object itself
event
the string event name.
target
previously "schema_item", the Table or MetaData object triggering the event.
connection
the Connection object in use for the operation.
\**kw
keyword arguments. In the case of MetaData before/after
create/drop, the list of Table objects for which
CREATE/DROP DDL is to be issued is passed as the kw
argument "tables". This is necessary for metadata-level
DDL that is dependent on the presence of specific tables.
The "schema_item" attribute of DDL has been renamed to
"target".
.. change::
:tags: dialect, refactor
:tickets:
Dialect modules are now broken into database dialects
plus DBAPI implementations. Connect URLs are now
preferred to be specified using dialect+driver://...,
i.e. "mysql+mysqldb://scott:tigerlocalhost/test". See
the 0.6 documentation for examples.
.. change::
:tags: dialect, refactor
:tickets:
the setuptools entrypoint for external dialects is now
called "sqlalchemy.dialects".
.. change::
:tags: dialect, refactor
:tickets:
the "owner" keyword argument is removed from Table. Use
"schema" to represent any namespaces to be prepended to
the table name.
.. change::
:tags: dialect, refactor
:tickets:
server_version_info becomes a static attribute.
.. change::
:tags: dialect, refactor
:tickets:
dialects receive an initialize() event on initial
connection to determine connection properties.
.. change::
:tags: dialect, refactor
:tickets:
dialects receive a visit_pool event have an opportunity
to establish pool listeners.
.. change::
:tags: dialect, refactor
:tickets:
cached TypeEngine classes are cached per-dialect class
instead of per-dialect.
.. change::
:tags: dialect, refactor
:tickets:
new UserDefinedType should be used as a base class for
new types, which preserves the 0.5 behavior of
get_col_spec().
.. change::
:tags: dialect, refactor
:tickets:
The result_processor() method of all type classes now
accepts a second argument "coltype", which is the DBAPI
type argument from cursor.description. This argument
can help some types decide on the most efficient processing
of result values.
.. change::
:tags: dialect, refactor
:tickets:
Deprecated Dialect.get_params() removed.
.. change::
:tags: dialect, refactor
:tickets:
Dialect.get_rowcount() has been renamed to a descriptor
"rowcount", and calls cursor.rowcount directly. Dialects
which need to hardwire a rowcount in for certain calls
should override the method to provide different behavior.
.. change::
:tags: dialect, refactor
:tickets: 1566
DefaultRunner and subclasses have been removed. The job
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.
.. change::
:tags: dialect, refactor
:tickets:
Functions and operators generated by the compiler now use
(almost) regular dispatch functions of the form
"visit_<opname>" and "visit_<funcname>_fn" to provide
customed processing. This replaces the need to copy the
"functions" and "operators" dictionaries in compiler
subclasses with straightforward visitor methods, and also
allows compiler subclasses complete control over
rendering, as the full _Function or _BinaryExpression
object is passed in.
.. change::
:tags: postgresql
:tickets:
New dialects: pg8000, zxjdbc, and pypostgresql
on py3k.
.. change::
:tags: postgresql
:tickets:
The "postgres" dialect is now named "postgresql" !
Connection strings look like:
postgresql://scott:tigerlocalhost/test
postgresql+pg8000://scott:tigerlocalhost/test
The "postgres" name remains for backwards compatibility
in the following ways:
- There is a "postgres.py" dummy dialect which
allows old URLs to work, i.e.
postgres://scott:tigerlocalhost/test
- The "postgres" name can be imported from the old
"databases" module, i.e. "from
sqlalchemy.databases import postgres" as well as
"dialects", "from sqlalchemy.dialects.postgres
import base as pg", will send a deprecation
warning.
- Special expression arguments are now named
"postgresql_returning" and "postgresql_where", but
the older "postgres_returning" and
"postgres_where" names still work with a
deprecation warning.
.. change::
:tags: postgresql
:tickets:
"postgresql_where" now accepts SQL expressions which
can also include literals, which will be quoted as needed.
.. change::
:tags: postgresql
:tickets:
The psycopg2 dialect now uses psycopg2's "unicode extension"
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.
.. change::
:tags: postgresql
:tickets: 1511
Added new ENUM type, which exists as a schema-level
construct and extends the generic Enum type. Automatically
associates itself with tables and their parent metadata
to issue the appropriate CREATE TYPE/DROP TYPE
commands as needed, supports unicode labels, supports
reflection.
.. change::
:tags: postgresql
:tickets:
INTERVAL supports an optional "precision" argument
corresponding to the argument that PG accepts.
.. change::
:tags: postgresql
:tickets:
using new dialect.initialize() feature to set up
version-dependent behavior.
.. change::
:tags: postgresql
:tickets: 1279
somewhat better support for % signs in table/column names;
psycopg2 can't handle a bind parameter name of
%(foobar)s however and SQLA doesn't want to add overhead
just to treat that one non-existent use case.
.. change::
:tags: postgresql
:tickets: 1516
Inserting NULL into a primary key + foreign key column
will allow the "not null constraint" error to raise,
not an attempt to execute a nonexistent "col_id_seq"
sequence.
.. change::
:tags: postgresql
:tickets:
autoincrement SELECT statements, i.e. those which
select from a procedure that modifies rows, now work
with server-side cursor mode (the named cursor isn't
used for such statements.)
.. change::
:tags: postgresql
:tickets: 1636
postgresql dialect can properly detect pg "devel" version
strings, i.e. "8.5devel"
.. change::
:tags: postgresql
:tickets: 1619
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.
.. change::
:tags: mysql
:tickets:
New dialects: oursql, a new native dialect,
MySQL Connector/Python, a native Python port of MySQLdb,
and of course zxjdbc on Jython.
.. change::
:tags: mysql
:tickets:
VARCHAR/NVARCHAR will not render without a length, raises
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.
.. change::
:tags: mysql
:tickets:
all the _detect_XXX() functions now run once underneath
dialect.initialize()
.. change::
:tags: mysql
:tickets: 1279
somewhat better support for % signs in table/column names;
MySQLdb can't handle % signs in SQL when executemany() is used,
and SQLA doesn't want to add overhead just to treat that one
non-existent use case.
.. change::
:tags: mysql
:tickets:
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.
.. change::
:tags: mysql
:tickets:
the "quoting='quoted'" argument to MSEnum/ENUM is deprecated.
It's best to rely upon the automatic quoting.
.. change::
:tags: mysql
:tickets:
ENUM now subclasses the new generic Enum type, and also handles
unicode values implicitly, if the given labelnames are unicode
objects.
.. change::
:tags: mysql
:tickets: 1539
a column of type TIMESTAMP now defaults to NULL if
"nullable=False" is not passed to Column(), and no default
is present. This is now consistent with all other types,
and in the case of TIMESTAMP explicitly renders "NULL"
due to MySQL's "switching" of default nullability
for TIMESTAMP columns.
.. change::
:tags: oracle
:tickets:
unit tests pass 100% with cx_oracle !
.. change::
:tags: oracle
:tickets:
support for cx_Oracle's "native unicode" mode which does
not require NLS_LANG to be set. Use the latest 5.0.2 or
later of cx_oracle.
.. change::
:tags: oracle
:tickets:
an NCLOB type is added to the base types.
.. change::
:tags: oracle
:tickets:
use_ansi=False won't leak into the FROM/WHERE clause of
a statement that's selecting from a subquery that also
uses JOIN/OUTERJOIN.
.. change::
:tags: oracle
:tickets: 1467
added native INTERVAL type to the dialect. This supports
only the DAY TO SECOND interval type so far due to lack
of support in cx_oracle for YEAR TO MONTH.
.. change::
:tags: oracle
:tickets:
usage of the CHAR type results in cx_oracle's
FIXED_CHAR dbapi type being bound to statements.
.. change::
:tags: oracle
:tickets: 885
the Oracle dialect now features NUMBER which intends
to act justlike Oracle's NUMBER type. It is the primary
numeric type returned by table reflection and attempts
to return Decimal()/float/int based on the precision/scale
parameters.
.. change::
:tags: oracle
:tickets:
func.char_length is a generic function for LENGTH
.. change::
:tags: oracle
:tickets:
ForeignKey() which includes onupdate=<value> will emit a
warning, not emit ON UPDATE CASCADE which is unsupported
by oracle
.. change::
:tags: oracle
:tickets:
the keys() method of RowProxy() now returns the result
column names *normalized* to be SQLAlchemy case
insensitive names. This means they will be lower case for
case insensitive names, whereas the DBAPI would normally
return them as UPPERCASE names. This allows row keys() to
be compatible with further SQLAlchemy operations.
.. change::
:tags: oracle
:tickets:
using new dialect.initialize() feature to set up
version-dependent behavior.
.. change::
:tags: oracle
:tickets: 1125
using types.BigInteger with Oracle will generate
NUMBER(19)
.. change::
:tags: oracle
:tickets:
"case sensitivity" feature will detect an all-lowercase
case-sensitive column name during reflect and add
"quote=True" to the generated Column, so that proper
quoting is maintained.
.. change::
:tags: firebird
:tickets:
the keys() method of RowProxy() now returns the result
column names *normalized* to be SQLAlchemy case
insensitive names. This means they will be lower case for
case insensitive names, whereas the DBAPI would normally
return them as UPPERCASE names. This allows row keys() to
be compatible with further SQLAlchemy operations.
.. change::
:tags: firebird
:tickets:
using new dialect.initialize() feature to set up
version-dependent behavior.
.. change::
:tags: firebird
:tickets:
"case sensitivity" feature will detect an all-lowercase
case-sensitive column name during reflect and add
"quote=True" to the generated Column, so that proper
quoting is maintained.
.. change::
:tags: mssql
:tickets:
MSSQL + Pyodbc + FreeTDS now works for the most part,
with possible exceptions regarding binary data as well as
unicode schema identifiers.
.. change::
:tags: mssql
:tickets:
the "has_window_funcs" flag is removed. LIMIT/OFFSET
usage will use ROW NUMBER as always, and if on an older
version of SQL Server, the operation fails. The behavior
is exactly the same except the error is raised by SQL
server instead of the dialect, and no flag setting is
required to enable it.
.. change::
:tags: mssql
:tickets:
the "auto_identity_insert" flag is removed. This feature
always takes effect when an INSERT statement overrides a
column that is known to have a sequence on it. As with
"has_window_funcs", if the underlying driver doesn't
support this, then you can't do this operation in any
case, so there's no point in having a flag.
.. change::
:tags: mssql
:tickets:
using new dialect.initialize() feature to set up
version-dependent behavior.
.. change::
:tags: mssql
:tickets:
removed references to sequence which is no longer used.
implicit identities in mssql work the same as implicit
sequences on any other dialects. Explicit sequences are
enabled through the use of "default=Sequence()". See
the MSSQL dialect documentation for more information.
.. change::
:tags: sqlite
:tickets:
DATE, TIME and DATETIME types can now take optional storage_format
and regexp argument. storage_format can be used to store those types
using a custom string format. regexp allows to use a custom regular
expression to match string values from the database.
.. change::
:tags: sqlite
:tickets:
Time and DateTime types now use by a default a stricter regular
expression to match strings from the database. Use the regexp
argument if you are using data stored in a legacy format.
.. change::
:tags: sqlite
:tickets:
__legacy_microseconds__ on SQLite Time and DateTime types is not
supported anymore. You should use the storage_format argument
instead.
.. change::
:tags: sqlite
:tickets:
Date, Time and DateTime types are now stricter in what they accept as
bind parameters: Date type only accepts date objects (and datetime
ones, because they inherit from date), Time only accepts time
objects, and DateTime only accepts date and datetime objects.
.. change::
:tags: sqlite
:tickets: 1016
Table() supports a keyword argument "sqlite_autoincrement", which
applies the SQLite keyword "AUTOINCREMENT" to the single integer
primary key column when generating DDL. Will prevent generation of
a separate PRIMARY KEY constraint.
.. change::
:tags: types
:tickets:
The construction of types within dialects has been totally
overhauled. Dialects now define publicly available types
as UPPERCASE names exclusively, and internal implementation
types using underscore identifiers (i.e. are private).
The system by which types are expressed in SQL and DDL
has been moved to the compiler system. This has the
effect that there are much fewer type objects within
most dialects. A detailed document on this architecture
for dialect authors is in
lib/sqlalchemy/dialects/type_migration_guidelines.txt .
.. change::
:tags: types
:tickets:
Types no longer make any guesses as to default
parameters. In particular, Numeric, Float, NUMERIC,
FLOAT, DECIMAL don't generate any length or scale unless
specified.
.. change::
:tags: types
:tickets: 1664
types.Binary is renamed to types.LargeBinary, it only
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.
.. change::
:tags: types
:tickets:
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.
.. change::
:tags: types
:tickets:
Most types result processors have been checked for possible speed
improvements. Specifically, the following generic types have been
optimized, resulting in varying speed improvements:
Unicode, PickleType, Interval, TypeDecorator, Binary.
Also the following dbapi-specific implementations have been improved:
Time, Date and DateTime on Sqlite, ARRAY on PostgreSQL,
Time on MySQL, Numeric(as_decimal=False) on MySQL, oursql and
pypostgresql, DateTime on cx_oracle and LOB-based types on cx_oracle.
.. change::
:tags: types
:tickets:
Reflection of types now returns the exact UPPERCASE
type within types.py, or the UPPERCASE type within
the dialect itself if the type is not a standard SQL
type. This means reflection now returns more accurate
information about reflected types.
.. change::
:tags: types
:tickets: 1511, 1109
Added a new Enum generic type. Enum is a schema-aware object
to support databases which require specific DDL in order to
use enum or equivalent; in the case of PG it handles the
details of `CREATE TYPE`, and on other databases without
native enum support will by generate VARCHAR + an inline CHECK
constraint to enforce the enum.
.. change::
:tags: types
:tickets: 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.
.. change::
:tags: types
:tickets: 1589
The Boolean type, when used on a backend that doesn't
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.
.. change::
:tags: types
:tickets:
PickleType now uses == for comparison of values when
mutable=True, unless the "comparator" argument with a
comparison function is specified to the type. Objects
being pickled will be compared based on identity (which
defeats the purpose of mutable=True) if __eq__() is not
overridden or a comparison function is not provided.
.. change::
:tags: types
:tickets:
The default "precision" and "scale" arguments of Numeric
and Float have been removed and now default to None.
NUMERIC and FLOAT will be rendered with no numeric
arguments by default unless these values are provided.
.. change::
:tags: types
:tickets:
AbstractType.get_search_list() is removed - the games
that was used for are no longer necessary.
.. change::
:tags: types
:tickets: 1125
Added a generic BigInteger type, compiles to
BIGINT or NUMBER(19).
.. change::
:tags: types
:tickets:
sqlsoup has been overhauled to explicitly support an 0.5 style
session, using autocommit=False, autoflush=True. Default
behavior of SQLSoup now requires the usual usage of commit()
and rollback(), which have been added to its interface. An
explicit Session or scoped_session can be passed to the
constructor, allowing these arguments to be overridden.
.. change::
:tags: types
:tickets:
sqlsoup db.<sometable>.update() and delete() now call
query(cls).update() and delete(), respectively.
.. change::
:tags: types
:tickets:
sqlsoup now has execute() and connection(), which call upon
the Session methods of those names, ensuring that the bind is
in terms of the SqlSoup object's bind.
.. change::
:tags: types
:tickets:
sqlsoup objects no longer have the 'query' attribute - it's
not needed for sqlsoup's usage paradigm and it gets in the
way of a column that is actually named 'query'.
.. change::
:tags: types
:tickets: 1259
The signature of the proxy_factory callable passed to
association_proxy is now (lazy_collection, creator,
value_attr, association_proxy), adding a fourth argument
that is the parent AssociationProxy argument. Allows
serializability and subclassing of the built in collections.
.. change::
:tags: types
:tickets: 1372
association_proxy now has basic comparator methods .any(),
.has(), .contains(), ==, !=, thanks to Scott Torborg.
=============
0.7 Changelog
=============
.. changelog::
:version: 0.7.11
:released:
.. change::
:tags: bug, engine
:tickets: 2851
:versions: 0.8.3, 0.9.0b1
The regexp used by the :func:`~sqlalchemy.engine.url.make_url` function now parses
ipv6 addresses, e.g. surrounded by brackets.
.. change::
:tags: bug, orm
:tickets: 2807
:versions: 0.8.3, 0.9.0b1
Fixed bug where list instrumentation would fail to represent a
setslice of ``[0:0]`` correctly, which in particular could occur
when using ``insert(0, item)`` with the association proxy. Due
to some quirk in Python collections, the issue was much more likely
with Python 3 rather than 2.
.. change::
:tags: bug, sql
:tickets: 2801
:versions: 0.8.3, 0.9.0b1
Fixed regression dating back to 0.7.9 whereby the name of a CTE might
not be properly quoted if it was referred to in multiple FROM clauses.
.. change::
:tags: mysql, bug
:tickets: 2791
:versions: 0.8.3, 0.9.0b1
Updates to MySQL reserved words for versions 5.5, 5.6, courtesy
Hanno Schlichting.
.. change::
:tags: sql, bug, cte
:tickets: 2783
:versions: 0.8.3, 0.9.0b1
Fixed bug in common table expression system where if the CTE were
used only as an ``alias()`` construct, it would not render using the
WITH keyword.
.. change::
:tags: bug, sql
:tickets: 2784
:versions: 0.8.3, 0.9.0b1
Fixed bug in :class:`.CheckConstraint` DDL where the "quote" flag from a
:class:`_schema.Column` object would not be propagated.
.. change::
:tags: bug, orm
:tickets: 2699
:versions: 0.8.1
Fixed bug when a query of the form:
``query(SubClass).options(subqueryload(Baseclass.attrname))``,
where ``SubClass`` is a joined inh of ``BaseClass``,
would fail to apply the ``JOIN`` inside the subquery
on the attribute load, producing a cartesian product.
The populated results still tended to be correct as additional
rows are just ignored, so this issue may be present as a
performance degradation in applications that are
otherwise working correctly.
.. change::
:tags: bug, orm
:tickets: 2689
:versions: 0.8.1
Fixed bug in unit of work whereby a joined-inheritance
subclass could insert the row for the "sub" table
before the parent table, if the two tables had no
ForeignKey constraints set up between them.
.. change::
:tags: feature, postgresql
:tickets: 2676
:versions: 0.8.0
Added support for PostgreSQL's traditional SUBSTRING
function syntax, renders as "SUBSTRING(x FROM y FOR z)"
when regular ``func.substring()`` is used.
Courtesy Gunnlaugur Þór Briem.
.. change::
:tags: bug, tests
:tickets: 2669
:pullreq: 41
Fixed an import of "logging" in test_execute which was not
working on some linux platforms.
.. change::
:tags: bug, orm
:tickets: 2674
Improved the error message emitted when a "backref loop" is detected,
that is when an attribute event triggers a bidirectional
assignment between two other attributes with no end.
This condition can occur not just when an object of the wrong
type is assigned, but also when an attribute is mis-configured
to backref into an existing backref pair.
.. change::
:tags: bug, orm
:tickets: 2674
A warning is emitted when a MapperProperty is assigned to a mapper
that replaces an existing property, if the properties in question
aren't plain column-based properties. Replacement of relationship
properties is rarely (ever?) what is intended and usually refers to a
mapper mis-configuration. This will also warn if a backref configures
itself on top of an existing one in an inheritance relationship
(which is an error in 0.8).
.. changelog::