Changelog
1.3.2
:released: April 2, 2019
.. change::
:tags: bug, documentation, sql
:tickets: 4580
Thanks to :ref:`change_3981`, we no longer need to rely on recipes that
subclass dialect-specific types directly, :class:`.TypeDecorator` can now
handle all cases. Additionally, the above change made it slightly less
likely that a direct subclass of a base SQLAlchemy type would work as
expected, which could be misleading. Documentation has been updated to use
:class:`.TypeDecorator` for these examples including the PostgreSQL
"ArrayOfEnum" example datatype and direct support for the "subclass a type
directly" has been removed.
.. change::
:tags: bug, postgresql
:tickets: 4550
Modified the :paramref:`.Select.with_for_update.of` parameter so that if a
join or other composed selectable is passed, the individual :class:`.Table`
objects will be filtered from it, allowing one to pass a join() object to
the parameter, as occurs normally when using joined table inheritance with
the ORM. Pull request courtesy Raymond Lu.
.. change::
:tags: feature, postgresql
:tickets: 4562
Added support for parameter-less connection URLs for the psycopg2 dialect,
meaning, the URL can be passed to :func:`.create_engine` as
``"postgresql+psycopg2://"`` with no additional arguments to indicate an
empty DSN passed to libpq, which indicates to connect to "localhost" with
no username, password, or database given. Pull request courtesy Julian
Mehnle.
.. change::
:tags: bug, orm, ext
:tickets: 4574, 4573
Restored instance-level support for plain Python descriptors, e.g.
``property`` objects, in conjunction with association proxies, in that if
the proxied object is not within ORM scope at all, it gets classified as
"ambiguous" but is proxed directly. For class level access, a basic class
level``__get__()`` now returns the
:class:`.AmbiguousAssociationProxyInstance` directly, rather than raising
its exception, which is the closest approximation to the previous behavior
that returned the :class:`.AssociationProxy` itself that's possible. Also
improved the stringification of these objects to be more descriptive of
current state.
.. change::
:tags: bug, orm
:tickets: 4537
Fixed bug where use of :func:`.with_polymorphic` or other aliased construct
would not properly adapt when the aliased target were used as the
:meth:`.Select.correlate_except` target of a subquery used inside of a
:func:`.column_property`. This required a fix to the clause adaption
mechanics to properly handle a selectable that shows up in the "correlate
except" list, in a similar manner as which occurs for selectables that show
up in the "correlate" list. This is ultimately a fairly fundamental bug
that has lasted for a long time but it is hard to come across it.
.. change::
:tags: bug, orm
:tickets: 4566
Fixed regression where a new error message that was supposed to raise when
attempting to link a relationship option to an AliasedClass without using
:meth:`.PropComparator.of_type` would instead raise an ``AttributeError``.
Note that in 1.3, it is no longer valid to create an option path from a
plain mapper relationship to an :class:`.AliasedClass` without using
:meth:`.PropComparator.of_type`.
.. changelog::
1.3.1
:released: March 9, 2019
.. change::
:tags: bug, mssql
:tickets: 4525
Fixed regression in SQL Server reflection due to :ticket:`4393` where the
removal of open-ended ``**kw`` from the :class:`.Float` datatype caused
reflection of this type to fail due to a "scale" argument being passed.
.. change::
:tags: bug, orm, ext
:tickets: 4522
Fixed regression where an association proxy linked to a synonym would no
longer work, both at instance level and at class level.
.. changelog::
1.3.0
:released: March 4, 2019
.. change::
:tags: feature, schema
:tickets: 4517
Added new parameters :paramref:`.Table.resolve_fks` and
:paramref:`.MetaData.reflect.resolve_fks` which when set to False will
disable the automatic reflection of related tables encountered in
:class:`.ForeignKey` objects, which can both reduce SQL overhead for omitted
tables as well as avoid tables that can't be reflected for database-specific
reasons. Two :class:`.Table` objects present in the same :class:`.MetaData`
collection can still refer to each other even if the reflection of the two
tables occurred separately.
.. change::
:tags: feature, orm
:tickets: 4316
The :meth:`.Query.get` method can now accept a dictionary of attribute keys
and values as a means of indicating the primary key value to load; is
particularly useful for composite primary keys. Pull request courtesy
Sanjana S.
.. change::
:tags: feature, orm
:tickets: 3133
A SQL expression can now be assigned to a primary key attribute for an ORM
flush in the same manner as ordinary attributes as described in
:ref:`flush_embedded_sql_expressions` where the expression will be evaulated
and then returned to the ORM using RETURNING, or in the case of pysqlite,
works using the cursor.lastrowid attribute.Requires either a database that
supports RETURNING (e.g. Postgresql, Oracle, SQL Server) or pysqlite.
.. change::
:tags: bug, sql
:tickets: 4509
The :class:`.Alias` class and related subclasses :class:`.CTE`,
:class:`.Lateral` and :class:`.TableSample` have been reworked so that it is
not possible for a user to construct the objects directly. These constructs
require that the standalone construction function or selectable-bound method
be used to instantiate new objects.
.. change::
:tags: feature, engine
:tickets: 4500
Revised the formatting for :class:`.StatementError` when stringified. Each
error detail is broken up over multiple newlines instead of spaced out on a
single line. Additionally, the SQL representation now stringifies the SQL
statement rather than using ``repr()``, so that newlines are rendered as is.
Pull request courtesy Nate Clark.
.. seealso::
:ref:`change_4500`
.. changelog::
1.3.0b3
:released: March 4, 2019
:released: February 8, 2019
.. change::
:tags: bug, ext
:tickets: 2642
Implemented a more comprehensive assignment operation (e.g. "bulk replace")
when using association proxy with sets or dictionaries. Fixes the problem
of redundant proxy objects being created to replace the old ones, which
leads to excessive events and SQL and in the case of unique constraints
will cause the flush to fail.
.. seealso::
:ref:`change_2642`
.. change::
:tags: bug, postgresql
:tickets: 4473
Fixed issue where using an uppercase name for an index type (e.g. GIST,
BTREE, etc. ) or an EXCLUDE constraint would treat it as an identifier to
be quoted, rather than rendering it as is. The new behavior converts these
types to lowercase and ensures they contain only valid SQL characters.
.. change::
:tags: bug, orm
:tickets: 4469
Improved the behavior of :func:`.orm.with_polymorphic` in conjunction with
loader options, in particular wildcard operations as well as
:func:`.orm.load_only`. The polymorphic object will be more accurately
targeted so that column-level options on the entity will correctly take
effect.The issue is a continuation of the same kinds of things fixed in
:ticket:`4468`.
.. change::
:tags: bug, sql
:tickets: 4481
Fully removed the behavior of strings passed directly as components of a
:func:`.select` or :class:`.Query` object being coerced to :func:`.text`
constructs automatically; the warning that has been emitted is now an
ArgumentError or in the case of order_by() / group_by() a CompileError.
This has emitted a warning since version 1.0 however its presence continues
to create concerns for the potential of mis-use of this behavior.
Note that public CVEs have been posted for order_by() / group_by() which
are resolved by this commit: CVE-2019-7164 CVE-2019-7548
.. seealso::
:ref:`change_4481`
.. change::
:tags: bug, sql
:tickets: 4467
Quoting is applied to :class:`.Function` names, those which are usually but
not necessarily generated from the :attr:`.sql.func` construct, at compile
time if they contain illegal characters, such as spaces or punctuation. The
names are as before treated as case insensitive however, meaning if the
names contain uppercase or mixed case characters, that alone does not
trigger quoting. The case insensitivity is currently maintained for
backwards compatibility.
.. change::
:tags: bug, sql
:tickets: 4481
Added "SQL phrase validation" to key DDL phrases that are accepted as plain
strings, including :paramref:`.ForeignKeyConstraint.on_delete`,
:paramref:`.ForeignKeyConstraint.on_update`,
:paramref:`.ExcludeConstraint.using`,
:paramref:`.ForeignKeyConstraint.initially`, for areas where a series of SQL
keywords only are expected.Any non-space characters that suggest the phrase
would need to be quoted will raise a :class:`.CompileError`. This change
is related to the series of changes committed as part of :ticket:`4481`.
.. change::
:tags: bug, orm, declarative
:tickets: 4470
Added some helper exceptions that invoke when a mapping based on
:class:`.AbstractConcreteBase`, :class:`.DeferredReflection`, or
:class:`.AutoMap` is used before the mapping is ready to be used, which
contain descriptive information on the class, rather than falling through
into other failure modes that are less informative.
.. change::
:tags: change, tests
:tickets: 4460
The test system has removed support for Nose, which is unmaintained for
several years and is producing warnings under Python 3. The test suite is
currently standardized on Pytest. Pull request courtesy Parth Shandilya.
.. changelog::
1.3.0b2
:released: March 4, 2019
:released: January 25, 2019
.. change::
:tags: bug, ext
:tickets: 4401
Fixed a regression in 1.3.0b1 caused by :ticket:`3423` where association
proxy objects that access an attribute that's only present on a polymorphic
subclass would raise an ``AttributeError`` even though the actual instance
being accessed was an instance of that subclass.
.. change::
:tags: bug, orm
:tickets: 1103
Fixed long-standing issue where duplicate collection members would cause a
backref to delete the association between the member and its parent object
when one of the duplicates were removed, as occurs as a side effect of
swapping two objects in one statement.
.. seealso::
:ref:`change_1103`
.. change::
:tags: bug, mssql
:tickets: 4442
The ``literal_processor`` for the :class:`.Unicode` and
:class:`.UnicodeText` datatypes now render an ``N`` character in front of
the literal string expression as required by SQL Server for Unicode string
values rendered in SQL expressions.
.. change::
:tags: feature, orm
:tickets: 4423
Implemented a new feature whereby the :class:`.AliasedClass` construct can
now be used as the target of a :func:`.relationship`. This allows the
concept of "non primary mappers" to no longer be necessary, as the
:class:`.AliasedClass` is much easier to configure and automatically inherits
all the relationships of the mapped class, as well as preserves the
ability for loader options to work normally.
.. seealso::
:ref:`change_4423`
.. change::
:tags: bug, orm
:tickets: 4373
Extended the fix first made as part of :ticket:`3287`, where a loader option
made against a subclass using a wildcard would extend itself to include
application of the wildcard to attributes on the super classes as well, to a
"bound" loader option as well, e.g. in an expression like
``Load(SomeSubClass).load_only('foo')``. Columns that are part of the
parent class of ``SomeSubClass`` will also be excluded in the same way as if
the unbound option ``load_only('foo')`` were used.
.. change::
:tags: bug, orm
:tickets: 4433
Improved error messages emitted by the ORM in the area of loader option
traversal. This includes early detection of mis-matched loader strategies
along with a clearer explanation why these strategies don't match.
.. change::
:tags: change, orm
:tickets: 4412
Added a new function :func:`.close_all_sessions` which takes
over the task of the :meth:`.Session.close_all` method, which
is now deprecated as this is confusing as a classmethod.
Pull request courtesy Augustin Trancart.
.. change::
:tags: feature, orm
:tickets: 4397
Added new :meth:`.MapperEvents.before_mapper_configured` event. This
event complements the other "configure" stage mapper events with a per
mapper event that receives each :class:`.Mapper` right before its
configure step, and additionally may be used to prevent or delay the
configuration of specific :class:`.Mapper` objects using a new
return value :attr:`.orm.interfaces.EXT_SKIP`. See the
documentation link for an example.
.. seealso::
:meth:`.MapperEvents.before_mapper_configured`
.. change::
:tags: bug, orm
The "remove" event for collections is now called before the item is removed
in the case of the ``collection.remove()`` method, as is consistent with the
behavior for most other forms of collection item removal (such as
``__delitem__``, replacement under ``__setitem__``). For ``pop()`` methods,
the remove event still fires after the operation.
.. change::
:tags: bug, orm declarative
:tickets: 4372
Added a ``__clause_element__()`` method to :class:`.ColumnProperty` which
can allow the usage of a not-fully-declared column or deferred attribute in
a declarative mapped class slightly more friendly when it's used in a
constraint or other column-oriented scenario within the class declaration,
though this still can't work in open-ended expressions; prefer to call the
:attr:`.ColumnProperty.expression` attribute if receiving ``TypeError``.
.. change::
:tags: bug, orm, engine
:tickets: 4464
Added accessors for execution options to Core and ORM, via
:meth:`.Query.get_execution_options`,
:meth:`.Connection.get_execution_options`,
:meth:`.Engine.get_execution_options`, and
:meth:`.Executable.get_execution_options`. PR courtesy Daniel Lister.
.. change::
:tags: bug, orm
:tickets: 4446
Fixed issue in association proxy due to :ticket:`3423` which caused the use
of custom :class:`.PropComparator` objects with hybrid attribites, such as
the one demonstrated in the ``dictlike-polymorphic`` example to not
function within an association proxy. The strictness that was added in
:ticket:`3423` has been relaxed, and additional logic to accomodate for
an association proxy that links to a custom hybrid have been added.
.. change::
:tags: change, general
:tickets: 4393
A large change throughout the library has ensured that all objects,
parameters, and behaviors which have been noted as deprecated or legacy now
emit ``DeprecationWarning`` warnings when invoked.As the Python 3
interpreter now defaults to displaying deprecation warnings, as well as that
modern test suites based on tools like tox and pytest tend to display
deprecation warnings, this change should make it easier to note what API
features are obsolete. A major rationale for this change is so that long-
deprecated features that nonetheless still see continue to see real world
use can finally be removed in the near future; the biggest example of this
are the :class:`.SessionExtension` and :class:`.MapperExtension` classes as
well as a handful of other pre-event extension hooks, which have been
deprecated since version 0.7 but still remain in the library. Another is
that several major longstanding behaviors are to be deprecated as well,
including the threadlocal engine strategy, the convert_unicode flag, and non
primary mappers.
.. seealso::
:ref:`change_4393_general`
.. change::
:tags: change, engine
:tickets: 4393
The "threadlocal" engine strategy which has been a legacy feature of
SQLAlchemy since around version 0.2 is now deprecated, along with the
:paramref:`.Pool.threadlocal` parameter of :class:`.Pool` which has no
effect in most modern use cases.
.. seealso::
:ref:`change_4393_threadlocal`
.. change::
:tags: change, sql
:tickets: 4393
The :paramref:`.create_engine.convert_unicode` and
:paramref:`.String.convert_unicode` parameters have been deprecated. These
parameters were built back when most Python DBAPIs had little to no support
for Python Unicode objects, and SQLAlchemy needed to take on the very
complex task of marshalling data and SQL strings between Unicode and
bytestrings throughout the system in a performant way. Thanks to Python 3,
DBAPIs were compelled to adapt to Unicode-aware APIs and today all DBAPIs
supported by SQLAlchemy support Unicode natively, including on Python 2,
allowing this long-lived and very complicated feature to finally be (mostly)
removed. There are still of course a few Python 2 edge cases where
SQLAlchemy has to deal with Unicode however these are handled automatically;
in modern use, there should be no need for end-user interaction with these
flags.
.. seealso::
:ref:`change_4393_convertunicode`
.. change::
:tags: bug, orm
:tickets: 3777
Implemented the ``.get_history()`` method, which also implies availability
of :attr:`.AttributeState.history`, for :func:`.synonym` attributes.
Previously, trying to access attribute history via a synonym would raise an
``AttributeError``.
.. change::
:tags: feature, engine
:tickets: 3689
Added public accessor :meth:`.QueuePool.timeout` that returns the configured
timeout for a :class:`.QueuePool` object. Pull request courtesy Irina Delamare.
.. change::
:tags: feature, sql
:tickets: 4386
Amended the :class:`.AnsiFunction` class, the base of common SQL
functions like ``CURRENT_TIMESTAMP``, to accept positional arguments
like a regular ad-hoc function. This to suit the case that many of
these functions on specific backends accept arguments such as
"fractional seconds" precision and such. If the function is created
with arguments, it renders the parenthesis and the arguments. If
no arguments are present, the compiler generates the non-parenthesized form.
.. changelog::
1.3.0b1
:released: March 4, 2019
:released: November 16, 2018
.. change::
:tags: bug, ext
:tickets: 3423
Reworked :class:`.AssociationProxy` to store state that's specific to a
parent class in a separate object, so that a single
:class:`.AssocationProxy` can serve for multiple parent classes, as is
intrinsic to inheritance, without any ambiguity in the state returned by it.
A new method :meth:`.AssociationProxy.for_class` is added to allow
inspection of class-specific state.
.. seealso::
:ref:`change_3423`
.. change::
:tags: bug, oracle
:tickets: 4369
Updated the parameters that can be sent to the cx_Oracle DBAPI to both allow
for all current parameters as well as for future parameters not added yet.
In addition, removed unused parameters that were deprecated in version 1.2,
and additionally we are now defaulting "threaded" to False.
.. seealso::
:ref:`change_4369`
.. change::
:tags: bug, oracle
:tickets: 4242
The Oracle dialect will no longer use the NCHAR/NCLOB datatypes
represent generic unicode strings or clob fields in conjunction with
:class:`.Unicode` and :class:`.UnicodeText` unless the flag
``use_nchar_for_unicode=True`` is passed to :func:`.create_engine` -
this includes CREATE TABLE behavior as well as ``setinputsizes()`` for
bound parameters. On the read side, automatic Unicode conversion under
Python 2 has been added to CHAR/VARCHAR/CLOB result rows, to match the
behavior of cx_Oracle under Python 3. In order to mitigate the performance
hit under Python 2, SQLAlchemy's very performant (when C extensions
are built) native Unicode handlers are used under Python 2.
.. seealso::
:ref:`change_4242`
.. change::
:tags: bug, orm
:tickets: 3844
Fixed issue regarding passive_deletes="all", where the foreign key
attribute of an object is maintained with its value even after the object
is removed from its parent collection. Previously, the unit of work would
set this to NULL even though passive_deletes indicated it should not be
modified.
.. seealso::
:ref:`change_3844`
.. change::
:tags: bug, ext
:tickets: 4268
The long-standing behavior of the association proxy collection maintaining
only a weak reference to the parent object is reverted; the proxy will now
maintain a strong reference to the parent for as long as the proxy
collection itself is also in memory, eliminating the "stale association
proxy" error. This change is being made on an experimental basis to see if
any use cases arise where it causes side effects.
.. seealso::
:ref:`change_4268`
.. change::
:tags: bug, sql
:tickets: 4302
Added "like" based operators as "comparison" operators, including
:meth:`.ColumnOperators.startswith` :meth:`.ColumnOperators.endswith`
:meth:`.ColumnOperators.ilike` :meth:`.ColumnOperators.notilike` among many
others, so that all of these operators can be the basis for an ORM
"primaryjoin" condition.
.. change::
:tags: feature, sqlite
:tickets: 3850
Added support for SQLite's json functionality via the new
SQLite implementation for :class:`.types.JSON`, :class:`.sqlite.JSON`.
The name used for the type is ``JSON``, following an example found at
SQLite's own documentation. Pull request courtesy Ilja Everilä.
.. seealso::
:ref:`change_3850`
.. change::
:tags: feature, engine
Added new "lifo" mode to :class:`.QueuePool`, typically enabled by setting
the flag :paramref:`.create_engine.pool_use_lifo` to True. "lifo" mode
means the same connection just checked in will be the first to be checked
out again, allowing excess connections to be cleaned up from the server
side during periods of the pool being only partially utilized. Pull request
courtesy Taem Park.
.. seealso::
:ref:`change_pr467`
.. change::
:tags: bug, orm
:tickets: 4359
Improved the behavior of a relationship-bound many-to-one object expression
such that the retrieval of column values on the related object are now
resilient against the object being detached from its parent
:class:`.Session`, even if the attribute has been expired. New features
within the :class:`.InstanceState` are used to memoize the last known value
of a particular column attribute before its expired, so that the expression
can still evaluate when the object is detached and expired at the same
time. Error conditions are also improved using modern attribute state
features to produce more specific messages as needed.
.. seealso::
:ref:`change_4359`
.. change::
:tags: feature, mysql
:tickets: 4219
Support added for the "WITH PARSER" syntax of CREATE FULLTEXT INDEX
in MySQL, using the ``mysql_with_parser`` keyword argument. Reflection
is also supported, which accommodates MySQL's special comment format
for reporting on this option as well. Additionally, the "FULLTEXT" and
"SPATIAL" index prefixes are now reflected back into the ``mysql_prefix``
index option.
.. change::
:tags: bug, orm, mysql, postgresql
:tickets: 4246
The ORM now doubles the "FOR UPDATE" clause within the subquery that
renders in conjunction with joined eager loading in some cases, as it has
been observed that MySQL does not lock the rows from a subquery. This
means the query renders with two FOR UPDATE clauses; note that on some
backends such as Oracle, FOR UPDATE clauses on subqueries are silently
ignored since they are unnecessary. Additionally, in the case of the "OF"
clause used primarily with PostgreSQL, the FOR UPDATE is rendered only on
the inner subquery when this is used so that the selectable can be targeted
to the table within the SELECT statement.
.. seealso::
:ref:`change_4246`
.. change::
:tags: feature, mssql
:tickets: 4158
Added ``fast_executemany=True`` parameter to the SQL Server pyodbc dialect,
which enables use of pyodbc's new performance feature of the same name
when using Microsoft ODBC drivers.
.. seealso::
:ref:`change_4158`
.. change::
:tags: bug, ext
:tickets: 4308
Fixed multiple issues regarding de-association of scalar objects with the
association proxy. ``del`` now works, and additionally a new flag
:paramref:`.AssociationProxy.cascade_scalar_deletes` is added, which when
set to True indicates that setting a scalar attribute to ``None`` or
deleting via ``del`` will also set the source association to ``None``.
.. seealso::
:ref:`change_4308`
.. change::
:tags: feature, ext
:tickets: 4318
Added new feature :meth:`.BakedQuery.to_query`, which allows for a
clean way of using one :class:`.BakedQuery` as a subquery inside of another
:class:`.BakedQuery` without needing to refer explicitly to a
:class:`.Session`.
.. change::
:tags: feature, sqlite
:tickets: 4360
Implemented the SQLite ``ON CONFLICT`` clause as understood at the DDL
level, e.g. for primary key, unique, and CHECK constraints as well as
specified on a :class:`.Column` to satisfy inline primary key and NOT NULL.
Pull request courtesy Denis Kataev.
.. seealso::
:ref:`change_4360`
.. change::
:tags: feature, postgresql
:tickets: 4237
Added rudimental support for reflection of PostgreSQL
partitioned tables, e.g. that relkind='p' is added to reflection
queries that return table information.
.. seealso::
:ref:`change_4237`
.. change::
:tags: feature, ext
:tickets: 4351
The :class:`.AssociationProxy` now has standard column comparison operations
such as :meth:`.ColumnOperators.like` and
:meth:`.ColumnOperators.startswith` available when the target attribute is a
plain column - the EXISTS expression that joins to the target table is
rendered as usual, but the column expression is then use within the WHERE
criteria of the EXISTS. Note that this alters the behavior of the
``.contains()`` method on the association proxy to make use of
:meth:`.ColumnOperators.contains` when used on a column-based attribute.
.. seealso::
:ref:`change_4351`
.. change::
:tags: feature, orm
Added new flag :paramref:`.Session.bulk_save_objects.preserve_order` to the
:meth:`.Session.bulk_save_objects` method, which defaults to True. When set
to False, the given mappings will be grouped into inserts and updates per
each object type, to allow for greater opportunities to batch common
operations together. Pull request courtesy Alessandro Cucci.
.. change::
:tags: bug, orm
:tickets: 4365
Refactored :meth:`.Query.join` to further clarify the individual components
of structuring the join. This refactor adds the ability for
:meth:`.Query.join` to determine the most appropriate "left" side of the
join when there is more than one element in the FROM list or the query is
against multiple entities. If more than one FROM/entity matches, an error
is raised that asks for an ON clause to be specified to resolve the
ambiguity. In particular this targets the regression we saw in
:ticket:`4363` but is also of general use. The codepaths within
:meth:`.Query.join` are now easier to follow and the error cases are
decided more specifically at an earlier point in the operation.
.. seealso::
:ref:`change_4365`
.. change::
:tags: bug, sql
:tickets: 3981
Fixed issue with :meth:`.TypeEngine.bind_expression` and
:meth:`.TypeEngine.column_expression` methods where these methods would not
work if the target type were part of a :class:`.Variant`, or other target
type of a :class:`.TypeDecorator`. Additionally, the SQL compiler now
calls upon the dialect-level implementation when it renders these methods
so that dialects can now provide for SQL-level processing for built-in
types.
.. seealso::
:ref:`change_3981`
.. change::
:tags: bug, orm
:tickets: 4304
Fixed long-standing issue in :class:`.Query` where a scalar subquery such
as produced by :meth:`.Query.exists`, :meth:`.Query.as_scalar` and other
derivations from :attr:`.Query.statement` would not correctly be adapted
when used in a new :class:`.Query` that required entity adaptation, such as
when the query were turned into a union, or a from_self(), etc. The change
removes the "no adaptation" annotation from the :func:`.select` object
produced by the :attr:`.Query.statement` accessor.
.. change::
:tags: bug, orm, declarative
:tickets: 4133
Fixed bug where declarative would not update the state of the
:class:`.Mapper` as far as what attributes were present, when additional
attributes were added or removed after the mapper attribute collections had
already been called and memoized. Addtionally, a ``NotImplementedError``
is now raised if a fully mapped attribute (e.g. column, relationship, etc.)
is deleted from a class that is currently mapped, since the mapper will not
function correctly if the attribute has been removed.
.. change::
:tags: bug, mssql
:tickets: 4362
Deprecated the use of :class:`.Sequence` with SQL Server in order to affect
the "start" and "increment" of the IDENTITY value, in favor of new
parameters ``mssql_identity_start`` and ``mssql_identity_increment`` which
set these parameters directly. :class:`.Sequence` will be used to generate
real ``CREATE SEQUENCE`` DDL with SQL Server in a future release.
.. seealso::
:ref:`change_4362`
.. change::
:tags: feature, mysql
Added support for the parameters in an ON DUPLICATE KEY UPDATE statement on
MySQL to be ordered, since parameter order in a MySQL UPDATE clause is
significant, in a similar manner as that described at
:ref:`updates_order_parameters`. Pull request courtesy Maxim Bublis.
.. seealso::
:ref:`change_mysql_ondupordering`
.. change::
:tags: feature, sql
:tickets: 4144
Added :class:`.Sequence` to the "string SQL" system that will render a
meaningful string expression (``"<next sequence value: my_sequence>"``)
when stringifying without a dialect a statement that includes a "sequence
nextvalue" expression, rather than raising a compilation error.
.. change::
:tags: bug, orm
:tickets: 4232
An informative exception is re-raised when a primary key value is not
sortable in Python during an ORM flush under Python 3, such as an ``Enum``
that has no ``__lt__()`` method; normally Python 3 raises a ``TypeError``
in this case. The flush process sorts persistent objects by primary key
in Python so the values must be sortable.
.. change::
:tags: orm, bug
:tickets: 3604
Removed the collection converter used by the :class:`.MappedCollection`
class. This converter was used only to assert that the incoming dictionary
keys matched that of their corresponding objects, and only during a bulk set
operation. The converter can interfere with a custom validator or
:meth:`.AttributeEvents.bulk_replace` listener that wants to convert
incoming values further. The ``TypeError`` which would be raised by this
converter when an incoming key didn't match the value is removed; incoming
values during a bulk assignment will be keyed to their value-generated key,
and not the key that's explicitly present in the dictionary.
Overall, converter is superseded by the
:meth:`.AttributeEvents.bulk_replace` event handler added as part of
:ticket:`3896`.
.. change::
:tags: feature, sql
:tickets: 3989
Added new naming convention tokens ``column_0N_name``, ``column_0_N_name``,
etc., which will render the names / keys / labels for all columns referenced
by a particular constraint in a sequence. In order to accommodate for the
length of such a naming convention, the SQL compiler's auto-truncation
feature now applies itself to constraint names as well, which creates a
shortened, deterministically generated name for the constraint that will
apply to a target backend without going over the character limit of that
backend.
The change also repairs two other issues. One is that the ``column_0_key``
token wasn't available even though this token was documented, the other was
that the ``referred_column_0_name`` token would inadvertently render the
``.key`` and not the ``.name`` of the column if these two values were
different.
.. seealso::
:ref:`change_3989`
.. change::
:tags: feature, ext
:tickets: 4196
Added support for bulk :meth:`.Query.update` and :meth:`.Query.delete`
to the :class:`.ShardedQuery` class within the horizontal sharding
extension. This also adds an additional expansion hook to the
bulk update/delete methods :meth:`.Query._execute_crud`.
.. seealso::
:ref:`change_4196`
.. change::
:tags: feature, sql
:tickets: 4271
Added new logic to the "expanding IN" bound parameter feature whereby if
the given list is empty, a special "empty set" expression that is specific
to different backends is generated, thus allowing IN expressions to be
fully dynamic including empty IN expressions.
.. seealso::
:ref:`change_4271`
.. change::
:tags: feature, mysql
The "pre-ping" feature of the connection pool now uses
the ``ping()`` method of the DBAPI connection in the case of
mysqlclient, PyMySQL and mysql-connector-python. Pull request
courtesy Maxim Bublis.
.. seealso::
:ref:`change_mysql_ping`
.. change::
:tags: feature, orm
:tickets: 4340
The "selectin" loader strategy now omits the JOIN in the case of a simple
one-to-many load, where it instead relies loads only from the related
table, relying upon the foreign key columns of the related table in order
to match up to primary keys in the parent table. This optimization can be
disabled by setting the :paramref:`.relationship.omit_join` flag to False.
Many thanks to Jayson Reis for the efforts on this.
.. seealso::
:ref:`change_4340`
.. change::
:tags: bug, orm
:tickets: 4353
Added new behavior to the lazy load that takes place when the "old" value of
a many-to-one is retrieved, such that exceptions which would be raised due
to either ``lazy="raise"`` or a detached session error are skipped.
.. seealso::
:ref:`change_4353`
.. change::
:tags: feature, sql
The Python builtin ``dir()`` is now supported for a SQLAlchemy "properties"
object, such as that of a Core columns collection (e.g. ``.c``),
``mapper.attrs``, etc. Allows iPython autocompletion to work as well.
Pull request courtesy Uwe Korn.
.. change::
:tags: feature, orm
:tickets: 4257
Added ``.info`` dictionary to the :class:`.InstanceState` class, the object
that comes from calling :func:`.inspect` on a mapped object.
.. seealso::
:ref:`change_4257`
.. change::
:tags: feature, sql
:tickets: 3831
Added new feature :meth:`.FunctionElement.as_comparison` which allows a SQL
function to act as a binary comparison operation that can work within the
ORM.
.. seealso::
:ref:`change_3831`
.. change::
:tags: bug, orm
:tickets: 4354
A long-standing oversight in the ORM, the ``__delete__`` method for a many-
to-one relationship was non-functional, e.g. for an operation such as ``del
a.b``. This is now implemented and is equivalent to setting the attribute
to ``None``.
.. seealso::
:ref:`change_4354`
1.2.18
:released: February 15, 2019
.. change::
:tags: bug, orm
:tickets: 4468
Fixed a regression in 1.2 where a wildcard/load_only loader option would
not work correctly against a loader path where of_type() were used to limit
to a particular subclass. The fix only works for of_type() of a simple
subclass so far, not a with_polymorphic entity which will be addressed in a
separate issue; it is unlikely this latter case was working previously.
.. change::
:tags: bug, orm
:tickets: 4489
Fixed fairly simple but critical issue where the
:meth:`.SessionEvents.pending_to_persistent` event would be invoked for
objects not just when they move from pending to persistent, but when they
were also already persistent and just being updated, thus causing the event
to be invoked for all objects on every update.
.. change::
:tags: bug, sql
:tickets: 4485
Fixed issue where the :class:`.JSON` type had a read-only
:attr:`.JSON.should_evaluate_none` attribute, which would cause failures
when making use of the :meth:`.TypeEngine.evaluates_none` method in
conjunction with this type. Pull request courtesy Sanjana S.
.. change::
:tags: bug, mssql
:tickets: 4499
Fixed bug where the SQL Server "IDENTITY_INSERT" logic that allows an INSERT
to proceed with an explicit value on an IDENTITY column was not detecting
the case where :meth:`.Insert.values` were used with a dictionary that
contained a :class:`.Column` as key and a SQL expression as a value.
.. change::
:tags: bug, sqlite
:tickets: 4474
Fixed bug in SQLite DDL where using an expression as a server side default
required that it be contained within parenthesis to be accepted by the
sqlite parser. Pull request courtesy Bartlomiej Biernacki.
.. change::
:tags: bug, mysql
:tickets: 4492
Fixed a second regression caused by :ticket:`4344` (the first was
:ticket:`4361`), which works around MySQL issue 88718, where the lower
casing function used was not correct for Python 2 with OSX/Windows casing
conventions, which would then raise ``TypeError``. Full coverage has been
added to this logic so that every codepath is exercised in a mock style for
all three casing conventions on all versions of Python. MySQL 8.0 has
meanwhile fixed issue 88718 so the workaround is only applies to a
particular span of MySQL 8.0 versions.
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