.. changelog::
:version: 1.3.0b1
- :include_notes_from: unreleased_13
+ :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 horiziontal 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`
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
