1.3 Changelog¶
1.3.25¶
no release dateorm¶
Fixed issue in
Session.bulk_save_objects()
when used with persistent objects which would fail to track the primary key of mappings where the column name of the primary key were different than the attribute name.References: #6392
schema¶
The
Table
object now raises an informative error message if it is instantiated without passing at least theTable.name
andTable.metadata
arguments positionally. Previously, if these were passed as keyword arguments, the object would silently fail to initialize correctly.References: #6135
postgresql¶
Fixed regression caused by #6023 where the PostgreSQL cast operator applied to elements within an
ARRAY
when using psycopg2 would fail to use the correct type in the case that the datatype were also embedded within an instance of theVariant
adapter.Additionally, repairs support for the correct CREATE TYPE to be emitted when using a
Variant(ARRAY(some_schema_type))
.References: #6182
mysql¶
Fixes to accommodate for the MariaDB 10.6 series, including backwards incompatible changes in both the mariadb-connector Python driver (supported on SQLAlchemy 1.4 only) as well as the native 10.6 client libraries that are used automatically by the mysqlclient DBAPI (applies to both 1.3 and 1.4). The “utf8mb3” encoding symbol is now reported by these client libraries when the encoding is stated as “utf8”, leading to lookup and encoding errors within the MySQL dialect that does not expect this symbol. Updates to both the MySQL base library to accommodate for this utf8mb3 symbol being reported as well as to the test suite. Thanks to Georg Richter for support.
sqlite¶
Add note regarding encryption-related pragmas for pysqlcipher passed in the url.
References: #6589
1.3.24¶
Released: March 30, 2021orm¶
Removed very old warning that states that passive_deletes is not intended for many-to-one relationships. While it is likely that in many cases placing this parameter on a many-to-one relationship is not what was intended, there are use cases where delete cascade may want to be disallowed following from such a relationship.
References: #5983
Fixed issue where the process of joining two tables could fail if one of the tables had an unrelated, unresolvable foreign key constraint which would raise
NoReferenceError
within the join process, which nonetheless could be bypassed to allow the join to complete. The logic which tested the exception for significance within the process would make assumptions about the construct which would fail.References: #5952
Fixed issue where the
MutableComposite
construct could be placed into an invalid state when the parent object was already loaded, and then covered by a subsequent query, due to the composite properties’ refresh handler replacing the object with a new one not handled by the mutable extension.References: #6001
engine¶
Fixed bug where the “schema_translate_map” feature failed to be taken into account for the use case of direct execution of
DefaultGenerator
objects such as sequences, which included the case where they were “pre-executed” in order to generate primary key values when implicit_returning was disabled.References: #5929
schema¶
Fixed bug first introduced in as some combination of #2892, #2919 nnd #3832 where the attachment events for a
TypeDecorator
would be doubled up against the “impl” class, if the “impl” were also aSchemaType
. The real-world case is anyTypeDecorator
againstEnum
orBoolean
would get a doubledCheckConstraint
when thecreate_constraint=True
flag is set.References: #6152
Fixed issue where the CHECK constraint generated by
Boolean
orEnum
would fail to render the naming convention correctly after the first compilation, due to an unintended change of state within the name given to the constraint. This issue was first introduced in 0.9 in the fix for issue #3067, and the fix revises the approach taken at that time which appears to have been more involved than what was needed.References: #6007
Repaired / implemented support for primary key constraint naming conventions that use column names/keys/etc as part of the convention. In particular, this includes that the
PrimaryKeyConstraint
object that’s automatically associated with aTable
will update its name as new primary keyColumn
objects are added to the table and then to the constraint. Internal failure modes related to this constraint construction process including no columns present, no name present or blank name present are now accommodated.References: #5919
Adjusted the logic that emits DROP statements for
Sequence
objects among the dropping of multiple tables, such that allSequence
objects are dropped after all tables, even if the givenSequence
is related only to aTable
object and not directly to the overallMetaData
object. The use case supports the sameSequence
being associated with more than oneTable
at a time.References: #6071
postgresql¶
Fixed issue where using
aggregate_order_by
would return ARRAY(NullType) under certain conditions, interfering with the ability of the result object to return data correctly.References: #5989
Fixed issue in PostgreSQL reflection where a column expressing “NOT NULL” will supersede the nullability of a corresponding domain.
References: #6161
Adjusted the psycopg2 dialect to emit an explicit PostgreSQL-style cast for bound parameters that contain ARRAY elements. This allows the full range of datatypes to function correctly within arrays. The asyncpg dialect already generated these internal casts in the final statement. This also includes support for array slice updates as well as the PostgreSQL-specific
ARRAY.contains()
method.References: #6023
mssql¶
Fixed issue regarding SQL Server reflection for older SQL Server 2005 version, a call to sp_columns would not proceed correctly without being prefixed with the EXEC keyword. This method is not used in current 1.4 series.
References: #5921
1.3.23¶
Released: February 1, 2021sql¶
Fixed bug where making use of the
TypeEngine.with_variant()
method on aTypeDecorator
type would fail to take into account the dialect-specific mappings in use, due to a rule inTypeDecorator
that was instead attempting to check for chains ofTypeDecorator
instances.References: #5816
postgresql¶
For SQLAlchemy 1.3 only, setup.py pins pg8000 to a version lower than 1.16.6. Version 1.16.6 and above is supported by SQLAlchemy 1.4. Pull request courtesy Giuseppe Lumia.
References: #5645
Fixed issue where using
Table.to_metadata()
(calledTable.tometadata()
in 1.3) in conjunction with a PostgreSQLExcludeConstraint
that made use of ad-hoc column expressions would fail to copy correctly.References: #5850
mysql¶
Casting to
FLOAT
is now supported in MySQL >= (8, 0, 17) and MariaDb >= (10, 4, 5).References: #5808
Fixed bug where MySQL server default reflection would fail for numeric values with a negation symbol present.
References: #5860
Fixed long-lived bug in MySQL dialect where the maximum identifier length of 255 was too long for names of all types of constraints, not just indexes, all of which have a size limit of 64. As metadata naming conventions can create too-long names in this area, apply the limit to the identifier generator within the DDL compiler.
References: #5898
Fixed deprecation warnings that arose as a result of the release of PyMySQL 1.0, including deprecation warnings for the “db” and “passwd” parameters now replaced with “database” and “password”.
References: #5821
Fixed regression from SQLAlchemy 1.3.20 caused by the fix for #5462 which adds double-parenthesis for MySQL functional expressions in indexes, as is required by the backend, this inadvertently extended to include arbitrary
text()
expressions as well as Alembic’s internal textual component, which are required by Alembic for arbitrary index expressions which don’t imply double parenthesis. The check has been narrowed to include only binary/ unary/functional expressions directly.References: #5800
oracle¶
Fixed regression in Oracle dialect introduced by #4894 in SQLAlchemy 1.3.11 where use of a SQL expression in RETURNING for an UPDATE would fail to compile, due to a check for “server_default” when an arbitrary SQL expression is not a column.
References: #5813
Fixed bug in Oracle dialect where retrieving a CLOB/BLOB column via
Insert.returning()
would fail as the LOB value would need to be read when returned; additionally, repaired support for retrieval of Unicode values via RETURNING under Python 2.References: #5812
misc¶
Fixed issue where the stringification that is sometimes called when attempting to generate the “key” for the
.c
collection on a selectable would fail if the column were an unlabeled custom SQL construct using thesqlalchemy.ext.compiler
extension, and did not provide a default compilation form; while this seems like an unusual case, it can get invoked for some ORM scenarios such as when the expression is used in an “order by” in combination with joined eager loading. The issue is that the lack of a default compiler function was raisingCompileError
and notUnsupportedCompilationError
.References: #5836
1.3.22¶
Released: December 18, 2020oracle¶
Fixed regression which occurred due to #5755 which implemented isolation level support for Oracle. It has been reported that many Oracle accounts don’t actually have permission to query the
v$transaction
view so this feature has been altered to gracefully fallback when it fails upon database connect, where the dialect will assume “READ COMMITTED” is the default isolation level as was the case prior to SQLAlchemy 1.3.21. However, explicit use of theConnection.get_isolation_level()
method must now necessarily raise an exception, as Oracle databases with this restriction explicitly disallow the user from reading the current isolation level.References: #5784
1.3.21¶
Released: December 17, 2020orm¶
Added a comprehensive check and an informative error message for the case where a mapped class, or a string mapped class name, is passed to
relationship.secondary
. This is an extremely common error which warrants a clear message.Additionally, added a new rule to the class registry resolution such that with regards to the
relationship.secondary
parameter, if a mapped class and its table are of the identical string name, theTable
will be favored when resolving this parameter. In all other cases, the class continues to be favored if a class and table share the identical name.References: #5774
Fixed bug in
Query.update()
where objects in the_ormsession.Session
that were already expired would be unnecessarily SELECTed individually when they were refreshed by the “evaluate”synchronize strategy.References: #5664
Fixed bug involving the
restore_load_context
option of ORM events such asInstanceEvents.load()
such that the flag would not be carried along to subclasses which were mapped after the event handler were first established.References: #5737
sql¶
A warning is emitted if a returning() method such as
Insert.returning()
is called multiple times, as this does not yet support additive operation. Version 1.4 will support additive operation for this. Additionally, any combination of theInsert.returning()
andValuesBase.return_defaults()
methods now raises an error as these methods are mutually exclusive; previously the operation would fail silently.References: #5691
Fixed structural compiler issue where some constructs such as MySQL / PostgreSQL “on conflict / on duplicate key” would rely upon the state of the
Compiler
object being fixed against their statement as the top level statement, which would fail in cases where those statements are branched from a different context, such as a DDL construct linked to a SQL statement.References: #5656
postgresql¶
Added new parameter
ExcludeConstraint.ops
to theExcludeConstraint
object, to support operator class specification with this constraint. Pull request courtesy Alon Menczer.References: #5604
Fixed regression introduced in 1.3.2 for the PostgreSQL dialect, also copied out to the MySQL dialect’s feature in 1.3.18, where usage of a non
Table
construct such astext()
as the argument toSelect.with_for_update.of
would fail to be accommodated correctly within the PostgreSQL or MySQL compilers.References: #5729
mysql¶
Fixed issue where reflecting a server default on MariaDB only that contained a decimal point in the value would fail to be reflected correctly, leading towards a reflected table that lacked any server default.
References: #5744
Added missing keywords to the
RESERVED_WORDS
list for the MySQL dialect:action
,level
,mode
,status
,text
,time
. Pull request courtesy Oscar Batori.References: #5696
sqlite¶
Added
sqlite_with_rowid=False
dialect keyword to enable creating tables asCREATE TABLE … WITHOUT ROWID
. Patch courtesy Sean Anderson.References: #5685
mssql¶
Fixed bug where a CREATE INDEX statement was rendered incorrectly when both
mssql-include
andmssql_where
were specified. Pull request courtesy @Adiorz.References: #5751
Added SQL Server code “01000” to the list of disconnect codes.
References: #5646
Fixed issue with composite primary key columns not being reported in the correct order. Patch courtesy @fulpm.
References: #5661
oracle¶
Implemented support for the SERIALIZABLE isolation level for Oracle databases, as well as a real implementation for
Connection.get_isolation_level()
.See also
oracle_isolation_level
References: #5755
1.3.20¶
Released: October 12, 2020orm¶
An
ArgumentError
with more detail is now raised if the target parameter forQuery.join()
is set to an unmapped object. Prior to this change a less detailedAttributeError
was raised. Pull request courtesy Ramon Williams.References: #4428
Fixed issue where using a loader option against a string attribute name that is not actually a mapped attribute, such as a plain Python descriptor, would raise an uninformative AttributeError; a descriptive error is now raised.
References: #4589
engine¶
Fixed issue where a non-string object sent to
SQLAlchemyError
or a subclass, as occurs with some third party dialects, would fail to stringify correctly. Pull request courtesy Andrzej Bartosiński.References: #5599
Repaired a function-level import that was not using SQLAlchemy’s standard late-import system within the sqlalchemy.exc module.
References: #5632
sql¶
Fixed issue where the
pickle.dumps()
operation againstOver
construct would produce a recursion overflow.References: #5644
Fixed bug where an error was not raised in the case where a
column()
were added to more than onetable()
at a time. This raised correctly for theColumn
andTable
objects. AnArgumentError
is now raised when this occurs.References: #5618
postgresql¶
The psycopg2 dialect now support PostgreSQL multiple host connections, by passing host/port combinations to the query string. Pull request courtesy Ramon Williams.
See also
psycopg2_multi_host
References: #4392
Adjusted the
Comparator.any()
andComparator.all()
methods to implement a straight “NOT” operation for negation, rather than negating the comparison operator.References: #5518
Fixed issue where the
ENUM
type would not consult the schema translate map when emitting a CREATE TYPE or DROP TYPE during the test to see if the type exists or not. Additionally, repaired an issue where if the same enum were encountered multiple times in a single DDL sequence, the “check” query would run repeatedly rather than relying upon a cached value.References: #5520
mysql¶
Adjusted the MySQL dialect to correctly parenthesize functional index expressions as accepted by MySQL 8. Pull request courtesy Ramon Williams.
References: #5462
Add new MySQL reserved words:
cube
,lateral
added in MySQL 8.0.1 and 8.0.14, respectively; this indicates that these terms will be quoted if used as table or column identifier names.References: #5539
The “skip_locked” keyword used with
with_for_update()
will emit a warning when used on MariaDB backends, and will then be ignored. This is a deprecated behavior that will raise in SQLAlchemy 1.4, as an application that requests “skip locked” is looking for a non-blocking operation which is not available on those backends.References: #5568
Fixed bug where an UPDATE statement against a JOIN using MySQL multi-table format would fail to include the table prefix for the target table if the statement had no WHERE clause, as only the WHERE clause were scanned to detect a “multi table update” at that particular point. The target is now also scanned if it’s a JOIN to get the leftmost table as the primary table and the additional entries as additional FROM entries.
References: #5617
mssql¶
Fixed issue where a SQLAlchemy connection URI for Azure DW with
authentication=ActiveDirectoryIntegrated
(and no username+password) was not constructing the ODBC connection string in a way that was acceptable to the Azure DW instance.References: #5592
tests¶
Fixed incompatibilities in the test suite when running against Pytest 6.x.
References: #5635
misc¶
Fixed issue where the following pool parameters were not being propagated to the new pool created when
Engine.dispose()
were called:pre_ping
,use_lifo
. Additionally therecycle
andreset_on_return
parameter is now propagated for theAssertionPool
class.References: #5582
An informative error is now raised when attempting to use an association proxy element as a plain column expression to be SELECTed from or used in a SQL function; this use case is not currently supported.
1.3.19¶
Released: August 17, 2020orm¶
Adjusted the workings of the
Mapper.all_orm_descriptors()
accessor to represent the attributes in the order that they are located in a deterministic way, assuming the use of Python 3.6 or higher which maintains the sorting order of class attributes based on how they were declared. This sorting is not guaranteed to match the declared order of attributes in all cases however; see the method documentation for the exact scheme.References: #5494
orm declarative¶
The name of the virtual column used when using the
AbstractConcreteBase
andConcreteBase
classes can now be customized, to allow for models that have a column that is actually namedtype
. Pull request courtesy Jesse-Bakker.References: #5513
sql¶
Repaired an issue where the “ORDER BY” clause rendering a label name rather than a complete expression, which is particularly important for SQL Server, would fail to occur if the expression were enclosed in a parenthesized grouping in some cases. This case has been added to test support. The change additionally adjusts the “automatically add ORDER BY columns when DISTINCT is present” behavior of ORM query, deprecated in 1.4, to more accurately detect column expressions that are already present.
References: #5470
The
LookupError
message will now provide the user with up to four possible values that a column is constrained to via theEnum
. Values longer than 11 characters will be truncated and replaced with ellipses. Pull request courtesy Ramon Williams.References: #4733
Fixed issue where the
Connection.execution_options.schema_translate_map
feature would not take effect when theSequence.next_value()
function function for aSequence
were used in theColumn.server_default
parameter and the create table DDL were emitted.References: #5500
postgresql¶
Fixed issue where the return type for the various RANGE comparison operators would itself be the same RANGE type rather than BOOLEAN, which would cause an undesirable result in the case that a
TypeDecorator
that defined result-processing behavior were in use. Pull request courtesy Jim Bosch.References: #5476
mysql¶
The MySQL dialect will render FROM DUAL for a SELECT statement that has no FROM clause but has a WHERE clause. This allows things like “SELECT 1 WHERE EXISTS (subquery)” kinds of queries to be used as well as other use cases.
References: #5481
Fixed an issue where CREATE TABLE statements were not specifying the COLLATE keyword correctly.
References: #5411
Added MariaDB code 1927 to the list of “disconnect” codes, as recent MariaDB versions apparently use this code when the database server was stopped.
References: #5493
sqlite¶
Applied a sweep through all included dialects to ensure names that contain single or double quotes are properly escaped when querying system tables, for all
Inspector
methods that accept object names as an argument (e.g. table names, view names, etc). SQLite and MSSQL contained two quoting issues that were repaired.References: #5456
mssql¶
Fixed bug where the mssql dialect incorrectly escaped object names that contained ‘]’ character(s).
References: #5467
misc¶
1.3.18¶
Released: June 25, 2020orm¶
Improve error message when using
Query.filter_by()
in a query where the first entity is not a mapped class.References: #5326
Added a new parameter
query_expression.default_expr
to thequery_expression()
construct, which will be appled to queries automatically if thewith_expression()
option is not used. Pull request courtesy Haoyu Sun.References: #5198
examples¶
Added new option
--raw
to the examples.performance suite which will dump the raw profile test for consumption by any number of profiling visualizer tools. Removed the “runsnake” option as runsnake is very hard to build at this point;
engine¶
Further refinements to the fixes to the “reset” agent fixed in #5326, which now emits a warning when it is not being correctly invoked and corrects for the behavior. Additional scenarios have been identified and fixed where this warning was being emitted.
References: #5326
Fixed issue in
URL
object where stringifying the object would not URL encode special characters, preventing the URL from being re-consumable as a real URL. Pull request courtesy Miguel Grinberg.References: #5341
sql¶
Added a “.schema” parameter to the
table()
construct, allowing ad-hoc table expressions to also include a schema name. Pull request courtesy Dylan Modesitt.References: #5309
Added
.offset
support to sybase dialect. Pull request courtesy Alan D. Snow.References: #5294
Correctly apply self_group in type_coerce element.
The type coerce element did not correctly apply grouping rules when using in an expression
References: #5344
Added
Select.with_hint()
output to the generic SQL string that is produced when callingstr()
on a statement. Previously, this clause would be omitted under the assumption that it was dialect specific. The hint text is presented within brackets to indicate the rendering of such hints varies among backends.References: #5353
Introduce
IdentityOptions
to store common parameters for sequences and identity columns.References: #5324
schema¶
Fixed issue where
dialect_options
were omitted when a database object (e.g.,Table
) was copied usingtometadata()
.References: #5276
mysql¶
Implemented row-level locking support for mysql. Pull request courtesy Quentin Somerville.
References: #4860
sqlite¶
SQLite 3.31 added support for computed column. This change enables their support in SQLAlchemy when targeting SQLite.
References: #5297
Added “exists” to the list of reserved words for SQLite so that this word will be quoted when used as a label or column name. Pull request courtesy Thodoris Sotiropoulos.
References: #5395
mssql¶
Moved the
supports_sane_rowcount_returning = False
requirement from thePyODBCConnector
level to theMSDialect_pyodbc
since pyodbc does work properly in some circumstances.References: #5321
Refined the logic used by the SQL Server dialect to interpret multi-part schema names that contain many dots, to not actually lose any dots if the name does not have bracking or quoting used, and additionally to support a “dbname” token that has many parts including that it may have multiple, independently-bracketed sections.
Fixed an issue in the pyodbc connector such that a warning about pyodbc “drivername” would be emitted when using a totally empty URL. Empty URLs are normal when producing a non-connected dialect object or when using the “creator” argument to create_engine(). The warning now only emits if the driver name is missing but other parameters are still present.
References: #5346
Fixed issue with assembling the ODBC connection string for the pyodbc DBAPI. Tokens containing semicolons and/or braces “{}” were not being correctly escaped, causing the ODBC driver to misinterpret the connection string attributes.
References: #5373
Fixed issue where
datetime.time
parameters were being converted todatetime.datetime
, making them incompatible with comparisons like>=
against an actualTIME
column.References: #5339
Fixed an issue where the
is_disconnect
function in the SQL Server pyodbc dialect was incorrectly reporting the disconnect state when the exception message had a substring that matched a SQL Server ODBC error code.References: #5359
oracle¶
Fixed bug in Oracle dialect where indexes that contain the full set of primary key columns would be mistaken as the primary key index itself, which is omitted, even if there were multiples. The check has been refined to compare the name of the primary key constraint against the index name itself, rather than trying to guess based on the columns present in the index.
References: #5421
1.3.17¶
Released: May 13, 2020orm¶
Added an accessor
Comparator.expressions
which provides access to the group of columns mapped under a multi-columnColumnProperty
attribute.References: #5262
Introduce
relationship.sync_backref
flag in a relationship to control if the synchronization events that mutate the in-Python attributes are added. This supersedes the previous change #5149, which warned thatviewonly=True
relationship target of a back_populates or backref configuration would be disallowed.References: #5237
Fixed bug where using
with_polymorphic()
as the target of a join viaRelationshipComparator.of_type()
on a mapper that already has a subquery-based with_polymorphic setting that’s equivalent to the one requested would not correctly alias the ON clause in the join.References: #5288
Fixed issue in the area of where loader options such as selectinload() interact with the baked query system, such that the caching of a query is not supposed to occur if the loader options themselves have elements such as with_polymorphic() objects in them that currently are not cache-compatible. The baked loader could sometimes not fully invalidate itself in these some of these scenarios leading to missed eager loads.
References: #5303
Modified the internal “identity set” implementation, which is a set that hashes objects on their id() rather than their hash values, to not actually call the
__hash__()
method of the objects, which are typically user-mapped objects. Some methods were calling this method as a side effect of the implementation.References: #5304
An informative error message is raised when an ORM many-to-one comparison is attempted against an object that is not an actual mapped instance. Comparisons such as those to scalar subqueries aren’t supported; generalized comparison with subqueries is better achieved using
Comparator.has()
.References: #5269
engine¶
Fixed fairly critical issue where the DBAPI connection could be returned to the connection pool while still in an un-rolled-back state. The reset agent responsible for rolling back the connection could be corrupted in the case that the transaction was “closed” without being rolled back or committed, which can occur in some scenarios when using ORM sessions and emitting .close() in a certain pattern involving savepoints. The fix ensures that the reset agent is always active.
References: #5326
schema¶
Fixed issue where an
Index
that is deferred in being associated with a table, such as as when it contains aColumn
that is not associated with anyTable
yet, would fail to attach correctly if it also contained a non table-oriented expression.References: #5298
A warning is emitted when making use of the
MetaData.sorted_tables
attribute as well as thesort_tables()
function, and the given tables cannot be correctly sorted due to a cyclic dependency between foreign key constraints. In this case, the functions will no longer sort the involved tables by foreign key, and a warning will be emitted. Other tables that are not part of the cycle will still be returned in dependency order. Previously, the sorted_table routines would return a collection that would unconditionally omit all foreign keys when a cycle was detected, and no warning was emitted.References: #5316
Add
comment
attribute toColumn
__repr__
method.References: #4138
postgresql¶
Added support for columns or type
ARRAY
ofEnum
,JSON
orJSONB
in PostgreSQL. Previously a workaround was required in these use cases.References: #5265
Raise an explicit
CompileError
when adding a table with a column of typeARRAY
ofEnum
configured withEnum.native_enum
set toFalse
whenEnum.create_constraint
is not set toFalse
References: #5266
mssql¶
Fix a regression introduced by the reflection of computed column in MSSQL when using the legacy TDS version 4.2. The dialect will try to detect the protocol version of first connect and run in compatibility mode if it cannot detect it.
References: #5255
Fix a regression introduced by the reflection of computed column in MSSQL when using SQL server versions before 2012, which does not support the
concat
function.References: #5271
oracle¶
Some modifications to how the cx_oracle dialect sets up per-column outputtype handlers for LOB and numeric datatypes to adjust for potential changes coming in cx_Oracle 8.
References: #5246
Changed the implementation of fetching CLOB and BLOB objects to use cx_Oracle’s native implementation which fetches CLOB/BLOB objects inline with other result columns, rather than performing a separate fetch. As always, this can be disabled by setting auto_convert_lobs to False.
As part of this change, the behavior of a CLOB that was given a blank string on INSERT now returns None on SELECT, which is now consistent with that of VARCHAR on Oracle.
References: #5314
firebird¶
Adjusted dialect loading for
firebird://
URIs so the external sqlalchemy-firebird dialect will be used if it has been installed, otherwise fall back to the (now deprecated) internal Firebird dialect.References: #5278
1.3.16¶
Released: April 7, 2020orm¶
Modified the queries used by subqueryload and selectinload to no longer ORDER BY the primary key of the parent entity; this ordering was there to allow the rows as they come in to be copied into lists directly with a minimal level of Python-side collation. However, these ORDER BY clauses can negatively impact the performance of the query as in many scenarios these columns are derived from a subquery or are otherwise not actual primary key columns such that SQL planners cannot make use of indexes. The Python-side collation uses the native itertools.group_by() to collate the incoming rows, and has been modified to allow multiple row-groups-per-parent to be assembled together using list.extend(), which should still allow for relatively fast Python-side performance. There will still be an ORDER BY present for a relationship that includes an explicit order_by parameter, however this is the only ORDER BY that will be added to the query for both kinds of loading.
References: #5162
Fixed bug in
selectinload()
loading option where two or more loaders that represent different relationships with the same string key name as referenced from a singlewith_polymorphic()
construct with multiple subclass mappers would fail to invoke each subqueryload separately, instead making use of a single string-based slot that would prevent the other loaders from being invoked.References: #5228
Fixed issue where a lazyload that uses session-local “get” against a target many-to-one relationship where an object with the correct primary key is present, however it’s an instance of a sibling class, does not correctly return None as is the case when the lazy loader actually emits a load for that row.
References: #5210
orm declarative¶
The string argument accepted as the first positional argument by the
relationship()
function when using the Declarative API is no longer interpreted using the Pythoneval()
function; instead, the name is dot separated and the names are looked up directly in the name resolution dictionary without treating the value as a Python expression. However, passing a string argument to the otherrelationship()
parameters that necessarily must accept Python expressions will still useeval()
; the documentation has been clarified to ensure that there is no ambiguity that this is in use.See also
Evaluation of relationship arguments - details on string evaluation
References: #5238
sql¶
Add ability to literal compile a
DateTime
,Date
orTime
when using the string dialect for debugging purposes. This change does not impact real dialect implementation that retain their current behavior.References: #5052
schema¶
Added support for reflection of “computed” columns, which are now returned as part of the structure returned by
Inspector.get_columns()
. When reflecting fullTable
objects, computed columns will be represented using theComputed
construct.References: #5063
postgresql¶
Fixed issue where a “covering” index, e.g. those which have an INCLUDE clause, would be reflected including all the columns in INCLUDE clause as regular columns. A warning is now emitted if these additional columns are detected indicating that they are currently ignored. Note that full support for “covering” indexes is part of #4458. Pull request courtesy Marat Sharafutdinov.
References: #5205
mysql¶
Fixed issue in MySQL dialect when connecting to a pseudo-MySQL database such as that provided by ProxySQL, the up front check for isolation level when it returns no row will not prevent the dialect from continuing to connect. A warning is emitted that the isolation level could not be detected.
References: #5239
sqlite¶
Implemented AUTOCOMMIT isolation level for SQLite when using pysqlite.
References: #5164
mssql¶
Added support for
ColumnOperators.is_distinct_from()
andColumnOperators.isnot_distinct_from()
to SQL Server, MySQL, and Oracle.References: #5137
oracle¶
Implemented AUTOCOMMIT isolation level for Oracle when using cx_Oracle. Also added a fixed default isolation level of READ COMMITTED for Oracle.
References: #5200
Fixed regression / incorrect fix caused by fix for #5146 where the Oracle dialect reads from the “all_tab_comments” view to get table comments but fails to accommodate for the current owner of the table being requested, causing it to read the wrong comment if multiple tables of the same name exist in multiple schemas.
References: #5146
tests¶
Fixed an issue that prevented the test suite from running with the recently released py.test 5.4.0.
References: #5201
misc¶
The
Enum
type now supports the parameterEnum.length
to specify the length of the VARCHAR column to create when using non native enums by settingEnum.native_enum
toFalse
References: #5183
Ensured that the “pyproject.toml” file is not included in builds, as the presence of this file indicates to pip that a pep-517 installation process should be used. As this mode of operation appears to be not well supported by current tools / distros, these problems are avoided within the scope of SQLAlchemy installation by omitting the file.
References: #5207
1.3.15¶
Released: March 11, 2020orm¶
Adjusted the error message emitted by
Query.join()
when a left hand side can’t be located that theQuery.select_from()
method is the best way to resolve the issue. Also, within the 1.3 series, used a deterministic ordering when determining the FROM clause from a given column entity passed toQuery
so that the same expression is determined each time.References: #5194
Fixed regression in 1.3.14 due to #4849 where a sys.exc_info() call failed to be invoked correctly when a flush error would occur. Test coverage has been added for this exception case.
References: #5196
1.3.14¶
Released: March 10, 2020general¶
Applied an explicit “cause” to most if not all internally raised exceptions that are raised from within an internal exception catch, to avoid misleading stacktraces that suggest an error within the handling of an exception. While it would be preferable to suppress the internally caught exception in the way that the
__suppress_context__
attribute would, there does not as yet seem to be a way to do this without suppressing an enclosing user constructed context, so for now it exposes the internally caught exception as the cause so that full information about the context of the error is maintained.References: #4849
orm¶
Added a new flag
InstanceEvents.restore_load_context
andSessionEvents.restore_load_context
which apply to theInstanceEvents.load()
,InstanceEvents.refresh()
, andSessionEvents.loaded_as_persistent()
events, which when set will restore the “load context” of the object after the event hook has been called. This ensures that the object remains within the “loader context” of the load operation that is already ongoing, rather than the object being transferred to a new load context due to refresh operations which may have occurred in the event. A warning is now emitted when this condition occurs, which recommends use of the flag to resolve this case. The flag is “opt-in” so that there is no risk introduced to existing applications.The change additionally adds support for the
raw=True
flag to session lifecycle events.References: #5129
Fixed regression caused in 1.3.13 by #5056 where a refactor of the ORM path registry system made it such that a path could no longer be compared to an empty tuple, which can occur in a particular kind of joined eager loading path. The “empty tuple” use case has been resolved so that the path registry is compared to a path registry in all cases; the
PathRegistry
object itself now implements__eq__()
and__ne__()
methods which will take place for all equality comparisons and continue to succeed in the not anticipated case that a non-PathRegistry
object is compared, while emitting a warning that this object should not be the subject of the comparison.References: #5110
Setting a relationship to viewonly=True which is also the target of a back_populates or backref configuration will now emit a warning and eventually be disallowed. back_populates refers specifically to mutation of an attribute or collection, which is disallowed when the attribute is subject to viewonly=True. The viewonly attribute is not subject to persistence behaviors which means it will not reflect correct results when it is locally mutated.
References: #5149
Fixed an additional regression in the same area as that of #5080 introduced in 1.3.0b3 via #4468 where the ability to create a joined option across a
with_polymorphic()
into a relationship against the base class of that with_polymorphic, and then further into regular mapped relationships would fail as the base class component would not add itself to the load path in a way that could be located by the loader strategy. The changes applied in #5080 have been further refined to also accommodate this scenario.References: #5121
engine¶
Expanded the scope of cursor/connection cleanup when a statement is executed to include when the result object fails to be constructed, or an after_cursor_execute() event raises an error, or autocommit / autoclose fails. This allows the DBAPI cursor to be cleaned up on failure and for connectionless execution allows the connection to be closed out and returned to the connection pool, where previously it waiting until garbage collection would trigger a pool return.
References: #5182
sql¶
Fixed bug where a CTE of an INSERT/UPDATE/DELETE that also uses RETURNING could then not be SELECTed from directly, as the internal state of the compiler would try to treat the outer SELECT as a DELETE statement itself and access nonexistent state.
References: #5181
postgresql¶
Fixed issue where the “schema_translate_map” feature would not work with a PostgreSQL native enumeration type (i.e.
Enum
,ENUM
) in that while the “CREATE TYPE” statement would be emitted with the correct schema, the schema would not be rendered in the CREATE TABLE statement at the point at which the enumeration was referenced.References: #5158
Fixed bug where PostgreSQL reflection of CHECK constraints would fail to parse the constraint if the SQL text contained newline characters. The regular expression has been adjusted to accommodate for this case. Pull request courtesy Eric Borczuk.
References: #5170
mysql¶
Fixed issue in MySQL
Insert.on_duplicate_key_update()
construct where using a SQL function or other composed expression for a column argument would not properly render theVALUES
keyword surrounding the column itself.References: #5173
mssql¶
Fixed issue where the
DATETIMEOFFSET
type would not accommodate for theNone
value, introduced as part of the series of fixes for this type first introduced in #4983, #5045. Additionally, added support for passing a backend-specific date formatted string through this type, as is typically allowed for date/time types on most other DBAPIs.References: #5132
oracle¶
Fixed a reflection bug where table comments could only be retrieved for tables actually owned by the user but not for tables visible to the user but owned by someone else. Pull request courtesy Dave Hirschfeld.
References: #5146
misc¶
Added keyword arguments to the
MutableList.sort()
function so that a key function as well as the “reverse” keyword argument can be provided.References: #5114
Revised an internal change to the test system added as a result of #5085 where a testing-related module per dialect would be loaded unconditionally upon making use of that dialect, pulling in SQLAlchemy’s testing framework as well as the ORM into the module import space. This would only impact initial startup time and memory to a modest extent, however it’s best that these additional modules aren’t reverse-dependent on straight Core usage.
References: #5180
Vendored the
inspect.formatannotation
function inside ofsqlalchemy.util.compat
, which is needed for the vendored version ofinspect.formatargspec
. The function is not documented in cPython and is not guaranteed to be available in future Python versions.References: #5138
1.3.13¶
Released: January 22, 2020orm¶
Identified a performance issue in the system by which a join is constructed based on a mapped relationship. The clause adaption system would be used for the majority of join expressions including in the common case where no adaptation is needed. The conditions under which this adaptation occur have been refined so that average non-aliased joins along a simple relationship without a “secondary” table use about 70% less function calls.
Added test support and repaired a wide variety of unnecessary reference cycles created for short-lived objects, mostly in the area of ORM queries. Thanks much to Carson Ip for the help on this.
Fixed regression in loader options introduced in 1.3.0b3 via #4468 where the ability to create a loader option using
PropComparator.of_type()
targeting an aliased entity that is an inheriting subclass of the entity which the preceding relationship refers to would fail to produce a matching path. See also #5082 fixed in this same release which involves a similar kind of issue.References: #5107
Fixed regression in joined eager loading introduced in 1.3.0b3 via #4468 where the ability to create a joined option across a
with_polymorphic()
into a polymorphic subclass usingRelationshipProperty.of_type()
and then further along regular mapped relationships would fail as the polymorphic subclass would not add itself to the load path in a way that could be located by the loader strategy. A tweak has been made to resolve this scenario.References: #5082
Repaired a warning in the ORM flush process that was not covered by test coverage when deleting objects that use the “version_id” feature. This warning is generally unreachable unless using a dialect that sets the “supports_sane_rowcount” flag to False, which is not typically the case however is possible for some MySQL configurations as well as older Firebird drivers, and likely some third party dialects.
References: #5068
Fixed bug where usage of joined eager loading would not properly wrap the query inside of a subquery when
Query.group_by()
were used against the query. When any kind of result-limiting approach is used, such as DISTINCT, LIMIT, OFFSET, joined eager loading embeds the row-limited query inside of a subquery so that the collection results are not impacted. For some reason, the presence of GROUP BY was never included in this criterion, even though it has a similar effect as using DISTINCT. Additionally, the bug would prevent using GROUP BY at all for a joined eager load query for most database platforms which forbid non-aggregated, non-grouped columns from being in the query, as the additional columns for the joined eager load would not be accepted by the database.References: #5065
engine¶
Fixed issue where the collection of value processors on a
Compiled
object would be mutated when “expanding IN” parameters were used with a datatype that has bind value processors; in particular, this would mean that when using statement caching and/or baked queries, the same compiled._bind_processors collection would be mutated concurrently. Since these processors are the same function for a given bind parameter namespace every time, there was no actual negative effect of this issue, however, the execution of aCompiled
object should never be causing any changes in its state, especially given that they are intended to be thread-safe and reusable once fully constructed.References: #5048
sql¶
A function created using
GenericFunction
can now specify that the name of the function should be rendered with or without quotes by assigning thequoted_name
construct to the .name element of the object. Prior to 1.3.4, quoting was never applied to function names, and some quoting was introduced in #4467 but no means to force quoting for a mixed case name was available. Additionally, thequoted_name
construct when used as the name will properly register its lowercase name in the function registry so that the name continues to be available via thefunc.
registry.See also
GenericFunction
References: #5079
postgresql¶
Added support for prefixes to the
CTE
construct, to allow support for Postgresql 12 “MATERIALIZED” and “NOT MATERIALIZED” phrases. Pull request courtesy Marat Sharafutdinov.See also
HasCTE.cte()
References: #5040
Fixed issue where the PostgreSQL dialect would fail to parse a reflected CHECK constraint that was a boolean-valued function (as opposed to a boolean-valued expression).
References: #5039
mssql¶
Fixed issue where a timezone-aware
datetime
value being converted to string for use as a parameter value of aDATETIMEOFFSET
column was omitting the fractional seconds.References: #5045
tests¶
Fixed a few test failures which would occur on Windows due to SQLite file locking issues, as well as some timing issues in connection pool related tests; pull request courtesy Federico Caselli.
References: #4946
Improved detection of two phase transactions requirement for the PostgreSQL database by testing that max_prepared_transactions is set to a value greater than 0. Pull request courtesy Federico Caselli.
References: #5057
misc¶
Fixed bug in sqlalchemy.ext.serializer where a unique
BindParameter
object could conflict with itself if it were present in the mapping itself, as well as the filter condition of the query, as one side would be used against the non-deserialized version and the other side would use the deserialized version. Logic is added toBindParameter
similar to its “clone” method which will uniquify the parameter name upon deserialize so that it doesn’t conflict with its original.References: #5086
1.3.12¶
Released: December 16, 2019orm¶
Fixed issue involving
lazy="raise"
strategy where an ORM delete of an object would raise for a simple “use-get” style many-to-one relationship that had lazy=”raise” configured. This is inconsistent vs. the change introduced in 1.3 as part of #4353, where it was established that a history operation that does not expect emit SQL should bypass thelazy="raise"
check, and instead effectively treat it aslazy="raise_on_sql"
for this case. The fix adjusts the lazy loader strategy to not raise for the case where the lazy load was instructed that it should not emit SQL if the object were not present.References: #4997
Fixed regression introduced in 1.3.0 related to the association proxy refactor in #4351 that prevented
composite()
attributes from working in terms of an association proxy that references them.References: #5000
Setting persistence-related flags on
relationship()
while also setting viewonly=True will now emit a regular warning, as these flags do not make sense for a viewonly=True relationship. In particular, the “cascade” settings have their own warning that is generated based on the individual values, such as “delete, delete-orphan”, that should not apply to a viewonly relationship. Note however that in the case of “cascade”, these settings are still erroneously taking effect even though the relationship is set up as “viewonly”. In 1.4, all persistence-related cascade settings will be disallowed on a viewonly=True relationship in order to resolve this issue.References: #4993
Fixed issue where when assigning a collection to itself as a slice, the mutation operation would fail as it would first erase the assigned collection inadvertently. As an assignment that does not change the contents should not generate events, the operation is now a no-op. Note that the fix only applies to Python 3; in Python 2, the
__setitem__
hook isn’t called in this case;__setslice__
is used instead which recreates the list item-by-item in all cases.References: #4990
Fixed issue where by if the “begin” of a transaction failed at the Core engine/connection level, such as due to network error or database is locked for some transactional recipes, within the context of the
Session
procuring that connection from the connection pool and then immediately returning it, the ORMSession
would not close the connection despite this connection not being stored within the state of thatSession
. This would lead to the connection being cleaned out by the connection pool weakref handler within garbage collection which is an unpreferred codepath that in some special configurations can emit errors in standard error.References: #5034
sql¶
Fixed bug where “distinct” keyword passed to
select()
would not treat a string value as a “label reference” in the same way that theselect.distinct()
does; it would instead raise unconditionally. This keyword argument and the others passed toselect()
will ultimately be deprecated for SQLAlchemy 2.0.References: #5028
Changed the text of the exception for “Can’t resolve label reference” to include other kinds of label coercions, namely that “DISTINCT” is also in this category under the PostgreSQL dialect.
sqlite¶
Fixed issue to workaround SQLite’s behavior of assigning “numeric” affinity to JSON datatypes, first described at Support for SQLite JSON Added, which returns scalar numeric JSON values as a number and not as a string that can be JSON deserialized. The SQLite-specific JSON deserializer now gracefully degrades for this case as an exception and bypasses deserialization for single numeric values, as from a JSON perspective they are already deserialized.
References: #5014
mssql¶
Repaired support for the
DATETIMEOFFSET
datatype on PyODBC, by adding PyODBC-level result handlers as it does not include native support for this datatype. This includes usage of the Python 3 “timezone” tzinfo subclass in order to set up a timezone, which on Python 2 makes use of a minimal backport of “timezone” in sqlalchemy.util.References: #4983
1.3.11¶
Released: November 11, 2019orm¶
Added accessor
Query.is_single_entity()
toQuery
, which will indicate if the results returned by thisQuery
will be a list of ORM entities, or a tuple of entities or column expressions. SQLAlchemy hopes to improve upon the behavior of single entity / tuples in future releases such that the behavior would be explicit up front, however this attribute should be helpful with the current behavior. Pull request courtesy Patrick Hayes.References: #4934
The
relationship.omit_join
flag was not intended to be manually set to True, and will now emit a warning when this occurs. The omit_join optimization is detected automatically, and theomit_join
flag was only intended to disable the optimization in the hypothetical case that the optimization may have interfered with correct results, which has not been observed with the modern version of this feature. Setting the flag to True when it is not automatically detected may cause the selectin load feature to not work correctly when a non-default primary join condition is in use.References: #4954
A warning is emitted if a primary key value is passed to
Query.get()
that consists of None for all primary key column positions. Previously, passing a single None outside of a tuple would raise aTypeError
and passing a composite None (tuple of None values) would silently pass through. The fix now coerces the single None into a tuple where it is handled consistently with the other None conditions. Thanks to Lev Izraelit for the help with this.References: #4915
The
BakedQuery
will not cache a query that was modified by aQueryEvents.before_compile()
event, so that compilation hooks that may be applying ad-hoc modifications to queries will take effect on each run. In particular this is helpful for events that modify queries used in lazy loading as well as eager loading such as “select in” loading. In order to re-enable caching for a query modified by this event, a new flagbake_ok
is added; see Using the before_compile event for details.A longer term plan to provide a new form of SQL caching should solve this kind of issue more comprehensively.
References: #4947
Fixed ORM bug where a “secondary” table that referred to a selectable which in some way would refer to the local primary table would apply aliasing to both sides of the join condition when a relationship-related join, either via
Query.join()
or byjoinedload()
, were generated. The “local” side is now excluded.References: #4974
engine¶
Fixed bug where parameter repr as used in logging and error reporting needs additional context in order to distinguish between a list of parameters for a single statement and a list of parameter lists, as the “list of lists” structure could also indicate a single parameter list where the first parameter itself is a list, such as for an array parameter. The engine/connection now passes in an additional boolean indicating how the parameters should be considered. The only SQLAlchemy backend that expects arrays as parameters is that of psycopg2 which uses pyformat parameters, so this issue has not been too apparent, however as other drivers that use positional gain more features it is important that this be supported. It also eliminates the need for the parameter repr function to guess based on the parameter structure passed.
References: #4902
Fixed bug in
Inspector
where the cache key generation did not take into account arguments passed in the form of tuples, such as the tuple of view name styles to return for the PostgreSQL dialect. This would lead the inspector to cache too generally for a more specific set of criteria. The logic has been adjusted to include every keyword element in the cache, as every argument is expected to be appropriate for a cache else the caching decorator should be bypassed by the dialect.References: #4955
sql¶
Added new accessors to expressions of type
JSON
to allow for specific datatype access and comparison, covering strings, integers, numeric, boolean elements. This revises the documented approach of CASTing to string when comparing values, instead adding specific functionality into the PostgreSQL, SQlite, MySQL dialects to reliably deliver these basic types in all cases.See also
JSON
Comparator.as_string()
Comparator.as_boolean()
Comparator.as_float()
Comparator.as_integer()
References: #4276
The
text()
construct now supports “unique” bound parameters, which will dynamically uniquify themselves on compilation thus allowing multipletext()
constructs with the same bound parameter names to be combined together.References: #4933
Changed the
repr()
of thequoted_name
construct to use regular string repr() under Python 3, rather than running it through “backslashreplace” escaping, which can be misleading.References: #4931
schema¶
Added DDL support for “computed columns”; these are DDL column specifications for columns that have a server-computed value, either upon SELECT (known as “virtual”) or at the point of which they are INSERTed or UPDATEd (known as “stored”). Support is established for Postgresql, MySQL, Oracle SQL Server and Firebird. Thanks to Federico Caselli for lots of work on this one.
References: #4894
Fixed bug where a table that would have a column label overlap with a plain column name, such as “foo.id AS foo_id” vs. “foo.foo_id”, would prematurely generate the
._label
attribute for a column before this overlap could be detected due to the use of theindex=True
orunique=True
flag on the column in conjunction with the default naming convention of"column_0_label"
. This would then lead to failures when._label
were used later to generate a bound parameter name, in particular those used by the ORM when generating the WHERE clause for an UPDATE statement. The issue has been fixed by using an alternate._label
accessor for DDL generation that does not affect the state of theColumn
. The accessor also bypasses the key-deduplication step as it is not necessary for DDL, the naming is now consistently"<tablename>_<columnname>"
without any subsequent numeric symbols when used in DDL.References: #4911
mysql¶
Added “Connection was killed” message interpreted from the base pymysql.Error class in order to detect closed connection, based on reports that this message is arriving via a pymysql.InternalError() object which indicates pymysql is not handling it correctly.
References: #4945
mssql¶
Fixed issue in MSSQL dialect where an expression-based OFFSET value in a SELECT would be rejected, even though the dialect can render this expression inside of a ROW NUMBER-oriented LIMIT/OFFSET construct.
References: #4973
Fixed an issue in the
Engine.table_names()
method where it would feed the dialect’s default schema name back into the dialect level table function, which in the case of SQL Server would interpret it as a dot-tokenized schema name as viewed by the mssql dialect, which would cause the method to fail in the case where the database username actually had a dot inside of it. In 1.3, this method is still used by theMetaData.reflect()
function so is a prominent codepath. In 1.4, which is the current master development branch, this issue doesn’t exist, both becauseMetaData.reflect()
isn’t using this method nor does the method pass the default schema name explicitly. The fix nonetheless guards against the default server name value returned by the dialect from being interpreted as dot-tokenized name under any circumstances by wrapping it in quoted_name().References: #4923
oracle¶
Added dialect-level flag
encoding_errors
to the cx_Oracle dialect, which can be specified as part ofcreate_engine()
. This is passed to SQLAlchemy’s unicode decoding converter under Python 2, and to cx_Oracle’scursor.var()
object as theencodingErrors
parameter under Python 3, for the very unusual case that broken encodings are present in the target database which cannot be fetched unless error handling is relaxed. The value is ultimately one of the Python “encoding errors” parameters passed todecode()
.References: #4799
Modified the approach of “name normalization” for the Oracle and Firebird dialects, which converts from the UPPERCASE-as-case-insensitive convention of these dialects into lowercase-as-case-insensitive for SQLAlchemy, to not automatically apply the
quoted_name
construct to a name that matches itself under upper or lower case conversion, as is the case for many non-european characters. All names used within metadata structures are converted toquoted_name
objects in any case; the change here would only affect the output of some inspection functions.References: #4931
The
NCHAR
datatype will now bind to thecx_Oracle.FIXED_NCHAR
DBAPI data bindings when used in a bound parameter, which supplies proper comparison behavior against a variable-length string. Previously, theNCHAR
datatype would bind tocx_oracle.NCHAR
which is not fixed length; theCHAR
datatype already binds tocx_Oracle.FIXED_CHAR
so it is now consistent thatNCHAR
binds tocx_Oracle.FIXED_NCHAR
.References: #4913
firebird¶
Added additional “disconnect” message “Error writing data to the connection” to Firebird disconnection detection. Pull request courtesy lukens.
References: #4903
tests¶
Fixed test failures which would occur with newer SQLite as of version 3.30 or greater, due to their addition of nulls ordering syntax as well as new restrictions on aggregate functions. Pull request courtesy Nils Philippsen.
References: #4920
misc¶
Added a workaround for a setuptools-related failure that has been observed as occurring on Windows installations, where setuptools is not correctly reporting a build error when the MSVC build dependencies are not installed and therefore not allowing graceful degradation into non C extensions builds.
References: #4967
1.3.10¶
Released: October 9, 2019mssql¶
Fixed bug in SQL Server dialect with new “max_identifier_length” feature where the mssql dialect already featured this flag, and the implementation did not accommodate for the new initialization hook correctly.
References: #4857
oracle¶
Fixed regression in Oracle dialect that was inadvertently using max identifier length of 128 characters on Oracle server 12.2 and greater even though the stated contract for the remainder of the 1.3 series is that this value stays at 30 until version SQLAlchemy 1.4. Also repaired issues with the retrieval of the “compatibility” version, and removed the warning emitted when the “v$parameter” view was not accessible as this was causing user confusion.
1.3.9¶
Released: October 4, 2019orm¶
Fixed regression in selectinload loader strategy caused by #4775 (released in version 1.3.6) where a many-to-one attribute of None would no longer be populated by the loader. While this was usually not noticeable due to the lazyloader populating None upon get, it would lead to a detached instance error if the object were detached.
References: #4872
Passing a plain string expression to
Session.query()
is deprecated, as all string coercions were removed in #4481 and this one should have been included. Theliteral_column()
function may be used to produce a textual column expression.References: #4873
A warning is emitted for a condition in which the
Session
may implicitly swap an object out of the identity map for another one with the same primary key, detaching the old one, which can be an observed result of load operations which occur within theSessionEvents.after_flush()
hook. The warning is intended to notify the user that some special condition has caused this to happen and that the previous object may not be in the expected state.References: #4890
engine¶
Added new
create_engine()
parametercreate_engine.max_identifier_length
. This overrides the dialect-coded “max identifier length” in order to accommodate for databases that have recently changed this length and the SQLAlchemy dialect has not yet been adjusted to detect for that version. This parameter interacts with the existingcreate_engine.label_length
parameter in that it establishes the maximum (and default) value for anonymously generated labels. Additionally, post-connection detection of max identifier lengths has been added to the dialect system. This feature is first being used by the Oracle dialect.See also
oracle_max_identifier_lengths - in the Oracle dialect documentation
References: #4857
sql¶
Added an explicit error message for the case when objects passed to
Table
are notSchemaItem
objects, rather than resolving to an attribute error.References: #4847
Characters that interfere with “pyformat” or “named” formats in bound parameters, namely
%, (, )
and the space character, as well as a few other typically undesirable characters, are stripped early for abindparam()
that is using an anonymized name, which is typically generated automatically from a named column which itself includes these characters in its name and does not use a.key
, so that they do not interfere either with the SQLAlchemy compiler’s use of string formatting or with the driver-level parsing of the parameter, both of which could be demonstrated before the fix. The change only applies to anonymized parameter names that are generated and consumed internally, not end-user defined names, so the change should have no impact on any existing code. Applies in particular to the psycopg2 driver which does not otherwise quote special parameter names, but also strips leading underscores to suit Oracle (but not yet leading numbers, as some anon parameters are currently entirely numeric/underscore based); Oracle in any case continues to quote parameter names that include special characters.References: #4837
sqlite¶
Added support for sqlite “URI” connections, which allow for sqlite-specific flags to be passed in the query string such as “read only” for Python sqlite3 drivers that support this.
See also
pysqlite_uri_connections
References: #4863
mssql¶
Added identifier quoting to the schema name applied to the “use” statement which is invoked when a SQL Server multipart schema name is used within a
Table
that is being reflected, as well as forInspector
methods such asInspector.get_table_names()
; this accommodates for special characters or spaces in the database name. Additionally, the “use” statement is not emitted if the current database matches the target owner database name being passed.References: #4883
oracle¶
The Oracle dialect now emits a warning if Oracle version 12.2 or greater is used, and the
create_engine.max_identifier_length
parameter is not set. The version in this specific case defaults to that of the “compatibility” version set in the Oracle server configuration, not the actual server version. In version 1.4, the default max_identifier_length for 12.2 or greater will move to 128 characters. In order to maintain forwards compatibility, applications should setcreate_engine.max_identifier_length
to 30 in order to maintain the same length behavior, or to 128 in order to test the upcoming behavior. This length determines among other things how generated constraint names are truncated for statements likeCREATE CONSTRAINT
andDROP CONSTRAINT
, which means a the new length may produce a name-mismatch against a name that was generated with the old length, impacting database migrations.See also
oracle_max_identifier_lengths - in the Oracle dialect documentation
References: #4857
Restored adding cx_Oracle.DATETIME to the setinputsizes() call when a SQLAlchemy
Date
,DateTime
orTime
datatype is used, as some complex queries require this to be present. This was removed in the 1.2 series for arbitrary reasons.References: #4886
tests¶
Fixed unit test regression released in 1.3.8 that would cause failure for Oracle, SQL Server and other non-native ENUM platforms due to new enumeration tests added as part of #4285 enum sortability in the unit of work; the enumerations created constraints that were duplicated on name.
References: #4285
1.3.8¶
Released: August 27, 2019orm¶
Added support for the use of an
Enum
datatype using Python pep-435 enumeration objects as values for use as a primary key column mapped by the ORM. As these values are not inherently sortable, as required by the ORM for primary keys, a newTypeEngine.sort_key_function
attribute is added to the typing system which allows any SQL type to implement a sorting for Python objects of its type which is consulted by the unit of work. TheEnum
type then defines this using the database value of a given enumeration. The sorting scheme can be also be redefined by passing a callable to theEnum.sort_key_function
parameter. Pull request courtesy Nicolas Caniart.References: #4285
Fixed bug where
Load
objects were not pickleable due to mapper/relationship state in the internal context dictionary. These objects are now converted to picklable using similar techniques as that of other elements within the loader option system that have long been serializable.References: #4823
engine¶
Added new parameter
create_engine.hide_parameters
which when set to True will cause SQL parameters to no longer be logged, nor rendered in the string representation of aStatementError
object.References: #4815
Fixed an issue whereby if the dialect “initialize” process which occurs on first connect would encounter an unexpected exception, the initialize process would fail to complete and then no longer attempt on subsequent connection attempts, leaving the dialect in an un-initialized, or partially initialized state, within the scope of parameters that need to be established based on inspection of a live connection. The “invoke once” logic in the event system has been reworked to accommodate for this occurrence using new, private API features that establish an “exec once” hook that will continue to allow the initializer to fire off on subsequent connections, until it completes without raising an exception. This does not impact the behavior of the existing
once=True
flag within the event system.References: #4807
postgresql¶
Added support for reflection of CHECK constraints that include the special PostgreSQL qualifier “NOT VALID”, which can be present for CHECK constraints that were added to an existing table with the directive that they not be applied to existing data in the table. The PostgreSQL dictionary for CHECK constraints as returned by
Inspector.get_check_constraints()
may include an additional entrydialect_options
which within will contain an entry"not_valid": True
if this symbol is detected. Pull request courtesy Bill Finn.References: #4824
Revised the approach for the just added support for the psycopg2 “execute_values()” feature added in 1.3.7 for #4623. The approach relied upon a regular expression that would fail to match for a more complex INSERT statement such as one which had subqueries involved. The new approach matches exactly the string that was rendered as the VALUES clause.
References: #4623
Fixed bug where Postgresql operators such as
Comparator.contains()
andComparator.contained_by()
would fail to function correctly for non-integer values when used against aarray
object, due to an erroneous assert statement.References: #4822
sqlite¶
Fixed bug where a FOREIGN KEY that was set up to refer to the parent table by table name only without the column names would not correctly be reflected as far as setting up the “referred columns”, since SQLite’s PRAGMA does not report on these columns if they weren’t given explicitly. For some reason this was hardcoded to assume the name of the local column, which might work for some cases but is not correct. The new approach reflects the primary key of the referred table and uses the constraint columns list as the referred columns list, if the remote column(s) aren’t present in the reflected pragma directly.
References: #4810
1.3.7¶
Released: August 14, 2019orm¶
Fixed regression caused by new selectinload for many-to-one logic where a primaryjoin condition not based on real foreign keys would cause KeyError if a related object did not exist for a given key value on the parent object.
References: #4777
Fixed bug where using
Query.first()
or a slice expression in conjunction with a query that has an expression based “offset” applied would raise TypeError, due to an “or” conditional against “offset” that did not expect it to be a SQL expression as opposed to an integer or None.References: #4803
sql¶
Fixed issue where
Index
object which contained a mixture of functional expressions which were not resolvable to a particular column, in combination with string-based column names, would fail to initialize its internal state correctly leading to failures during DDL compilation.References: #4778
Fixed bug where
TypeEngine.column_expression()
method would not be applied to subsequent SELECT statements inside of a UNION or other_selectable.CompoundSelect
, even though the SELECT statements are rendered at the topmost level of the statement. New logic now differentiates between rendering the column expression, which is needed for all SELECTs in the list, vs. gathering the returned data type for the result row, which is needed only for the first SELECT.References: #4787
Fixed issue where internal cloning of SELECT constructs could lead to a key error if the copy of the SELECT changed its state such that its list of columns changed. This was observed to be occurring in some ORM scenarios which may be unique to 1.3 and above, so is partially a regression fix.
References: #4780
postgresql¶
Added new dialect flag for the psycopg2 dialect,
executemany_mode
which supersedes the previous experimentaluse_batch_mode
flag.executemany_mode
supports both the “execute batch” and “execute values” functions provided by psycopg2, the latter which is used for compiledinsert()
constructs. Pull request courtesy Yuval Dinari.See also
psycopg2_executemany_mode
References: #4623
mysql¶
Added reserved words ARRAY and MEMBER to the MySQL reserved words list, as MySQL 8.0 has now made these reserved.
References: #4783
The MySQL dialects will emit “SET NAMES” at the start of a connection when charset is given to the MySQL driver, to appease an apparent behavior observed in MySQL 8.0 that raises a collation error when a UNION includes string columns unioned against columns of the form CAST(NULL AS CHAR(..)), which is what SQLAlchemy’s polymorphic_union function does. The issue seems to have affected PyMySQL for at least a year, however has recently appeared as of mysqlclient 1.4.4 based on changes in how this DBAPI creates a connection. As the presence of this directive impacts three separate MySQL charset settings which each have intricate effects based on their presence, SQLAlchemy will now emit the directive on new connections to ensure correct behavior.
References: #4804
Added another fix for an upstream MySQL 8 issue where a case sensitive table name is reported incorrectly in foreign key constraint reflection, this is an extension of the fix first added for #4344 which affects a case sensitive column name. The new issue occurs through MySQL 8.0.17, so the general logic of the 88718 fix remains in place.
See also
https://bugs.mysql.com/bug.php?id=96365 - upstream bug
References: #4751
sqlite¶
The dialects that support json are supposed to take arguments
json_serializer
andjson_deserializer
at the create_engine() level, however the SQLite dialect calls them_json_serializer
and_json_deserilalizer
. The names have been corrected, the old names are accepted with a change warning, and these parameters are now documented ascreate_engine.json_serializer
andcreate_engine.json_deserializer
.References: #4798
Fixed bug where usage of “PRAGMA table_info” in SQLite dialect meant that reflection features to detect for table existence, list of table columns, and list of foreign keys, would default to any table in any attached database, when no schema name was given and the table did not exist in the base schema. The fix explicitly runs PRAGMA for the ‘main’ schema and then the ‘temp’ schema if the ‘main’ returned no rows, to maintain the behavior of tables + temp tables in the “no schema” namespace, attached tables only in the “schema” namespace.
References: #4793
mssql¶
Added new
try_cast()
construct for SQL Server which emits “TRY_CAST” syntax. Pull request courtesy Leonel Atencio.References: #4782
misc¶
Fixed issue in event system where using the
once=True
flag with dynamically generated listener functions would cause event registration of future events to fail if those listener functions were garbage collected after they were used, due to an assumption that a listened function is strongly referenced. The “once” wrapped is now modified to strongly reference the inner function persistently, and documentation is updated that using “once” does not imply automatic de-registration of listener functions.References: #4794
1.3.6¶
Released: July 21, 2019orm¶
Added new loader option method
Load.options()
which allows loader options to be constructed hierarchically, so that many sub-options can be applied to a particular path without needing to calldefaultload()
many times. Thanks to Alessio Bogon for the idea.References: #4736
The optimization applied to selectin loading in #4340 where a JOIN is not needed to eagerly load related items is now applied to many-to-one relationships as well, so that only the related table is queried for a simple join condition. In this case, the related items are queried based on the value of a foreign key column on the parent; if these columns are deferred or otherwise not loaded on any of the parent objects in the collection, the loader falls back to the JOIN method.
References: #4775
Fixed regression caused by #4365 where a join from an entity to itself without using aliases no longer raises an informative error message, instead failing on an assertion. The informative error condition has been restored.
References: #4773
Fixed an issue where the
_ORMJoin.join()
method, which is a not-internally-used ORM-level method that exposes what is normally an internal process ofQuery.join()
, did not propagate thefull
andouterjoin
keyword arguments correctly. Pull request courtesy Denis Kataev.References: #4713
Fixed bug where a many-to-one relationship that specified
uselist=True
would fail to update correctly during a primary key change where a related column needs to change.References: #4772
Fixed bug where the detection for many-to-one or one-to-one use with a “dynamic” relationship, which is an invalid configuration, would fail to raise if the relationship were configured with
uselist=True
. The current fix is that it warns, instead of raises, as this would otherwise be backwards incompatible, however in a future release it will be a raise.References: #4772
Fixed bug where a synonym created against a mapped attribute that does not exist yet, as is the case when it refers to backref before mappers are configured, would raise recursion errors when trying to test for attributes on it which ultimately don’t exist (as occurs when the classes are run through Sphinx autodoc), as the unconfigured state of the synonym would put it into an attribute not found loop.
References: #4767
engine¶
Fixed bug where using reflection function such as
MetaData.reflect()
with anEngine
object that had execution options applied to it would fail, as the resultingOptionEngine
proxy object failed to include a.engine
attribute used within the reflection routines.References: #4754
sql¶
Adjusted the initialization for
Enum
to minimize how often it invokes the.__members__
attribute of a given PEP-435 enumeration object, to suit the case where this attribute is expensive to invoke, as is the case for some popular third party enumeration libraries.References: #4758
Fixed issue where the
array_agg
construct in combination withFunctionElement.filter()
would not produce the correct operator precedence in combination with the array index operator.References: #4760
Fixed an unlikely issue where the “corresponding column” routine for unions and other
_selectable.CompoundSelect
objects could return the wrong column in some overlapping column situations, thus potentially impacting some ORM operations when set operations are in use, if the underlyingselect()
constructs were used previously in other similar kinds of routines, due to a cached value not being cleared.References: #4747
postgresql¶
Added support for reflection of indexes on PostgreSQL partitioned tables, which was added to PostgreSQL as of version 11.
References: #4771
Added support for multidimensional Postgresql array literals via nesting the
array
object within another one. The multidimensional array type is detected automatically.See also
array
References: #4756
mysql¶
Fixed bug where the special logic to render “NULL” for the
TIMESTAMP
datatype whennullable=True
would not work if the column’s datatype were aTypeDecorator
or aVariant
. The logic now ensures that it unwraps down to the originalTIMESTAMP
so that this special case NULL keyword is correctly rendered when requested.References: #4743
Enhanced MySQL/MariaDB version string parsing to accommodate for exotic MariaDB version strings where the “MariaDB” word is embedded among other alphanumeric characters such as “MariaDBV1”. This detection is critical in order to correctly accommodate for API features that have split between MySQL and MariaDB such as the “transaction_isolation” system variable.
References: #4624
sqlite¶
Added support for composite (tuple) IN operators with SQLite, by rendering the VALUES keyword for this backend. As other backends such as DB2 are known to use the same syntax, the syntax is enabled in the base compiler using a dialect-level flag
tuple_in_values
. The change also includes support for “empty IN tuple” expressions for SQLite when using “in_()” between a tuple value and an empty set.References: #4766
mssql¶
Ensured that the queries used to reflect indexes and view definitions will explicitly CAST string parameters into NVARCHAR, as many SQL Server drivers frequently treat string values, particularly those with non-ascii characters or larger string values, as TEXT which often don’t compare correctly against VARCHAR characters in SQL Server’s information schema tables for some reason. These CAST operations already take place for reflection queries against SQL Server
information_schema.
tables but were missing from three additional queries that are againstsys.
tables.References: #4745
1.3.5¶
Released: June 17, 2019orm¶
Fixed a series of related bugs regarding joined table inheritance more than two levels deep, in conjunction with modification to primary key values, where those primary key columns are also linked together in a foreign key relationship as is typical for joined table inheritance. The intermediary table in a three-level inheritance hierarchy will now get its UPDATE if only the primary key value has changed and passive_updates=False (e.g. foreign key constraints not being enforced), whereas before it would be skipped; similarly, with passive_updates=True (e.g. ON UPDATE CASCADE in effect), the third-level table will not receive an UPDATE statement as was the case earlier which would fail since CASCADE already modified it. In a related issue, a relationship linked to a three-level inheritance hierarchy on the primary key of an intermediary table of a joined-inheritance hierarchy will also correctly have its foreign key column updated when the parent object’s primary key is modified, even if that parent object is a subclass of the linked parent class, whereas before these classes would not be counted.
References: #4723
Fixed bug where the
Mapper.all_orm_descriptors
accessor would return an entry for theMapper
itself under the declarative__mapper__
key, when this is not a descriptor. The.is_attribute
flag that’s present on allInspectionAttr
objects is now consulted, which has also been modified to beTrue
for an association proxy, as it was erroneously set to False for this object.References: #4729
Fixed regression in
Query.join()
where thealiased=True
flag would not properly apply clause adaptation to filter criteria, if a previous join were made to the same entity. This is because the adapters were placed in the wrong order. The order has been reversed so that the adapter for the most recentaliased=True
call takes precedence as was the case in 1.2 and earlier. This broke the “elementtree” examples among other things.References: #4704
Replaced the Python compatibility routines for
getfullargspec()
with a fully vendored version from Python 3.3. Originally, Python was emitting deprecation warnings for this function in Python 3.8 alphas. While this change was reverted, it was observed that Python 3 implementations forgetfullargspec()
are an order of magnitude slower as of the 3.4 series where it was rewritten againstSignature
. While Python plans to improve upon this situation, SQLAlchemy projects for now are using a simple replacement to avoid any future issues.References: #4674
Reworked the attribute mechanics used by
AliasedClass
to no longer rely upon calling__getattribute__
on the MRO of the wrapped class, and to instead resolve the attribute normally on the wrapped class using getattr(), and then unwrap/adapt that. This allows a greater range of attribute styles on the mapped class including special__getattr__()
schemes; but it also makes the code simpler and more resilient in general.References: #4694
sql¶
Fixed a series of quoting issues which all stemmed from the concept of the
literal_column()
construct, which when being “proxied” through a subquery to be referred towards by a label that matches its text, the label would not have quoting rules applied to it, even if the string in theLabel
were set up as aquoted_name
construct. Not applying quoting to the text of theLabel
is a bug because this text is strictly a SQL identifier name and not a SQL expression, and the string should not have quotes embedded into it already unlike theliteral_column()
which it may be applied towards. The existing behavior of a non-labeledliteral_column()
being propagated as is on the outside of a subquery is maintained in order to help with manual quoting schemes, although it’s not clear if valid SQL can be generated for such a construct in any case.References: #4730
postgresql¶
Added support for column sorting flags when reflecting indexes for PostgreSQL, including ASC, DESC, NULLSFIRST, NULLSLAST. Also adds this facility to the reflection system in general which can be applied to other dialects in future releases. Pull request courtesy Eli Collins.
References: #4717
Fixed bug where PostgreSQL dialect could not correctly reflect an ENUM datatype that has no members, returning a list with
None
for theget_enums()
call and raising a TypeError when reflecting a column which has such a datatype. The inspection now returns an empty list.References: #4701
mysql¶
Fixed bug where MySQL ON DUPLICATE KEY UPDATE would not accommodate setting a column to the value NULL. Pull request courtesy Lukáš Banič.
References: #4715
1.3.4¶
Released: May 27, 2019orm¶
Fixed issue where the
AttributeEvents.active_history
flag would not be set for an event listener that propagated to a subclass via theAttributeEvents.propagate
flag. This bug has been present for the full span of theAttributeEvents
system.References: #4695
Fixed regression where new association proxy system was still not proxying hybrid attributes when they made use of the
@hybrid_property.expression
decorator to return an alternate SQL expression, or when the hybrid returned an arbitraryPropComparator
, at the expression level. This involved further generalization of the heuristics used to detect the type of object being proxied at the level ofQueryableAttribute
, to better detect if the descriptor ultimately serves mapped classes or column expressions.References: #4690
Applied the mapper “configure mutex” against the declarative class mapping process, to guard against the race which can occur if mappers are used while dynamic module import schemes are still in the process of configuring mappers for related classes. This does not guard against all possible race conditions, such as if the concurrent import has not yet encountered the dependent classes as of yet, however it guards against as much as possible within the SQLAlchemy declarative process.
References: #4686
A warning is now emitted for the case where a transient object is being merged into the session with
Session.merge()
when that object is already transient in theSession
. This warns for the case where the object would normally be double-inserted.References: #4647
Fixed regression in new relationship m2o comparison logic first introduced at Improvement to the behavior of many-to-one query expressions when comparing to an attribute that is persisted as NULL and is in an un-fetched state in the mapped instance. Since the attribute has no explicit default, it needs to default to NULL when accessed in a persistent setting.
References: #4676
engine¶
Moved the “rollback” which occurs during dialect initialization so that it occurs after additional dialect-specific initialize steps, in particular those of the psycopg2 dialect which would inadvertently leave transactional state on the first new connection, which could interfere with some psycopg2-specific APIs which require that no transaction is started. Pull request courtesy Matthew Wilkes.
References: #4663
sql¶
Fixed that the
GenericFunction
class was inadvertently registering itself as one of the named functions. Pull request courtesy Adrien Berchet.References: #4653
Fixed issue where double negation of a boolean column wouldn’t reset the “NOT” operator.
References: #4618
The
GenericFunction
namespace is being migrated so that function names are looked up in a case-insensitive manner, as SQL functions do not collide on case sensitive differences nor is this something which would occur with user-defined functions or stored procedures. Lookups for functions declared withGenericFunction
now use a case insensitive scheme, however a deprecation case is supported which allows two or moreGenericFunction
objects with the same name of different cases to exist, which will cause case sensitive lookups to occur for that particular name, while emitting a warning at function registration time. Thanks to Adrien Berchet for a lot of work on this complicated feature.References: #4569
postgresql¶
Fixed an issue where the “number of rows matched” warning would emit even if the dialect reported “supports_sane_multi_rowcount=False”, as is the case for psycogp2 with
use_batch_mode=True
and others.References: #4661
mysql¶
Added support for DROP CHECK constraint which is required by MySQL 8.0.16 to drop a CHECK constraint; MariaDB supports plain DROP CONSTRAINT. The logic distinguishes between the two syntaxes by checking the server version string for MariaDB presence. Alembic migrations has already worked around this issue by implementing its own DROP for MySQL / MariaDB CHECK constraints, however this change implements it straight in Core so that its available for general use. Pull request courtesy Hannes Hansen.
References: #4650
mssql¶
Added support for SQL Server filtered indexes, via the
mssql_where
parameter which works similarly to that of thepostgresql_where
index function in the PostgreSQL dialect.See also
mssql_index_where
References: #4657
Added error code 20047 to “is_disconnect” for pymssql. Pull request courtesy Jon Schuff.
References: #4680
misc¶
Removed errant “sqla_nose.py” symbol from MANIFEST.in which created an undesirable warning message.
References: #4625
1.3.3¶
Released: April 15, 2019orm¶
Fixed 1.3 regression in new “ambiguous FROMs” query logic introduced in Query.join() handles ambiguity in deciding the “left” side more explicitly where a
Query
that explicitly places an entity in the FROM clause withQuery.select_from()
and also joins to it usingQuery.join()
would later cause an “ambiguous FROM” error if that entity were used in additional joins, as the entity appears twice in the “from” list of theQuery
. The fix resolves this ambiguity by folding the standalone entity into the join that it’s already a part of in the same way that ultimately happens when the SELECT statement is rendered.References: #4584
Adjusted the
Query.filter_by()
method to not calland()
internally against multiple criteria, instead passing it off toQuery.filter()
as a series of criteria, instead of a single criteria. This allowsQuery.filter_by()
to defer toQuery.filter()
’s treatment of variable numbers of clauses, including the case where the list is empty. In this case, theQuery
object will not have a.whereclause
, which allows subsequent “no whereclause” methods likeQuery.select_from()
to behave consistently.References: #4606
postgresql¶
Fixed regression from release 1.3.2 caused by #4562 where a URL that contained only a query string and no hostname, such as for the purposes of specifying a service file with connection information, would no longer be propagated to psycopg2 properly. The change in #4562 has been adjusted to further suit psycopg2’s exact requirements, which is that if there are any connection parameters whatsoever, the “dsn” parameter is no longer required, so in this case the query string parameters are passed alone.
References: #4601
mssql¶
Fixed issue in SQL Server dialect where if a bound parameter were present in an ORDER BY expression that would ultimately not be rendered in the SQL Server version of the statement, the parameters would still be part of the execution parameters, leading to DBAPI-level errors. Pull request courtesy Matt Lewellyn.
References: #4587
misc¶
Fixed behavioral regression as a result of deprecating the “use_threadlocal” flag for
Pool
, where theSingletonThreadPool
no longer makes use of this option which causes the “rollback on return” logic to take place when the sameEngine
is used multiple times in the context of a transaction to connect or implicitly execute, thereby cancelling the transaction. While this is not the recommended way to work with engines and connections, it is nonetheless a confusing behavioral change as when usingSingletonThreadPool
, the transaction should stay open regardless of what else is done with the same engine in the same thread. Theuse_threadlocal
flag remains deprecated however theSingletonThreadPool
now implements its own version of the same logic.References: #4585
Fixed bug where using
copy.copy()
orcopy.deepcopy()
onMutableList
would cause the items within the list to be duplicated, due to an inconsistency in how Python pickle and copy both make use of__getstate__()
and__setstate__()
regarding lists. In order to resolve, a__reduce_ex__
method had to be added toMutableList
. In order to maintain backwards compatibility with existing pickles based on__getstate__()
, the__setstate__()
method remains as well; the test suite asserts that pickles made against the old version of the class can still be deserialized by the pickle module.References: #4603
1.3.2¶
Released: April 2, 2019orm¶
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 theAmbiguousAssociationProxyInstance
directly, rather than raising its exception, which is the closest approximation to the previous behavior that returned theAssociationProxy
itself that’s possible. Also improved the stringification of these objects to be more descriptive of current state.Fixed bug where use of
with_polymorphic()
or other aliased construct would not properly adapt when the aliased target were used as theSelect.correlate_except()
target of a subquery used inside of acolumn_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.References: #4537
Fixed regression where a new error message that was supposed to raise when attempting to link a relationship option to an AliasedClass without using
PropComparator.of_type()
would instead raise anAttributeError
. Note that in 1.3, it is no longer valid to create an option path from a plain mapper relationship to anAliasedClass
without usingPropComparator.of_type()
.References: #4566
sql¶
Thanks to TypeEngine methods bind_expression, column_expression work with Variant, type-specific types, we no longer need to rely on recipes that subclass dialect-specific types directly,
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 useTypeDecorator
for these examples including the PostgreSQL “ArrayOfEnum” example datatype and direct support for the “subclass a type directly” has been removed.References: #4580
postgresql¶
Added support for parameter-less connection URLs for the psycopg2 dialect, meaning, the URL can be passed to
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.References: #4562
Modified the
Select.with_for_update.of
parameter so that if a join or other composed selectable is passed, the individualTable
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.References: #4550
1.3.1¶
Released: March 9, 2019orm¶
Fixed regression where an association proxy linked to a synonym would no longer work, both at instance level and at class level.
References: #4522
mssql¶
A commit() is emitted after an isolation level change to SNAPSHOT, as both pyodbc and pymssql open an implicit transaction which blocks subsequent SQL from being emitted in the current transaction.
This change is also backported to: 1.2.19
References: #4536
Fixed regression in SQL Server reflection due to #4393 where the removal of open-ended
**kw
from theFloat
datatype caused reflection of this type to fail due to a “scale” argument being passed.References: #4525
1.3.0¶
Released: March 4, 2019orm¶
The
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.References: #4316
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 Embedding SQL Insert/Update Expressions into a Flush where the expression will be evaluated 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.
References: #3133
engine¶
Revised the formatting for
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 usingrepr()
, so that newlines are rendered as is. Pull request courtesy Nate Clark.References: #4500
sql¶
The
Alias
class and related subclassesCTE
,Lateral
andTableSample
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.References: #4509
schema¶
Added new parameters
Table.resolve_fks
andMetaData.reflect.resolve_fks
which when set to False will disable the automatic reflection of related tables encountered inForeignKey
objects, which can both reduce SQL overhead for omitted tables as well as avoid tables that can’t be reflected for database-specific reasons. TwoTable
objects present in the sameMetaData
collection can still refer to each other even if the reflection of the two tables occurred separately.References: #4517
1.3.0b3¶
Released: February 8, 2019orm¶
Improved the behavior of
with_polymorphic()
in conjunction with loader options, in particular wildcard operations as well asload_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 #4468.References: #4469
orm declarative¶
Added some helper exceptions that invoke when a mapping based on
AbstractConcreteBase
,DeferredReflection
, orAutoMap
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.References: #4470
sql¶
Fully removed the behavior of strings passed directly as components of a
select()
orQuery
object being coerced totext()
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
References: #4481
Quoting is applied to
Function
names, those which are usually but not necessarily generated from thesqlalchemy.sql.expression.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.References: #4467
Added “SQL phrase validation” to key DDL phrases that are accepted as plain strings, including
ForeignKeyConstraint.on_delete
,ForeignKeyConstraint.on_update
,ExcludeConstraint.using
,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 aCompileError
. This change is related to the series of changes committed as part of #4481.References: #4481
postgresql¶
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.
References: #4473
tests¶
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.
References: #4460
misc¶
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.
References: #2642
1.3.0b2¶
Released: January 25, 2019general¶
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 theSessionExtension
andMapperExtension
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.References: #4393
orm¶
Implemented a new feature whereby the
AliasedClass
construct can now be used as the target of arelationship()
. This allows the concept of “non primary mappers” to no longer be necessary, as theAliasedClass
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.References: #4423
Added new
MapperEvents.before_mapper_configured()
event. This event complements the other “configure” stage mapper events with a per mapper event that receives eachMapper
right before its configure step, and additionally may be used to prevent or delay the configuration of specificMapper
objects using a new return valueinterfaces.EXT_SKIP
. See the documentation link for an example.See also
MapperEvents.before_mapper_configured()
References: #4397
Added a new function
close_all_sessions()
which takes over the task of theSession.close_all()
method, which is now deprecated as this is confusing as a classmethod. Pull request courtesy Augustin Trancart.References: #4412
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.
References: #1103
Extended the fix first made as part of #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 ofSomeSubClass
will also be excluded in the same way as if the unbound optionload_only('foo')
were used.References: #4373
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.
References: #4433
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__
). Forpop()
methods, the remove event still fires after the operation.Added accessors for execution options to Core and ORM, via
Query.get_execution_options()
,Connection.get_execution_options()
,Engine.get_execution_options()
, andExecutable.get_execution_options()
. PR courtesy Daniel Lister.References: #4464
Fixed issue in association proxy due to #3423 which caused the use of custom
PropComparator
objects with hybrid attributes, such as the one demonstrated in thedictlike-polymorphic
example to not function within an association proxy. The strictness that was added in #3423 has been relaxed, and additional logic to accommodate for an association proxy that links to a custom hybrid have been added.References: #4446
Implemented the
.get_history()
method, which also implies availability ofAttributeState.history
, forsynonym()
attributes. Previously, trying to access attribute history via a synonym would raise anAttributeError
.References: #3777
orm declarative¶
Added a
__clause_element__()
method toColumnProperty
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 theColumnProperty.expression
attribute if receivingTypeError
.References: #4372
engine¶
Added public accessor
QueuePool.timeout()
that returns the configured timeout for aQueuePool
object. Pull request courtesy Irina Delamare.References: #3689
The “threadlocal” engine strategy which has been a legacy feature of SQLAlchemy since around version 0.2 is now deprecated, along with the
Pool.threadlocal
parameter ofPool
which has no effect in most modern use cases.References: #4393
sql¶
Amended the
AnsiFunction
class, the base of common SQL functions likeCURRENT_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.References: #4386
The
create_engine.convert_unicode
andString.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.References: #4393
mssql¶
The
literal_processor
for theUnicode
andUnicodeText
datatypes now render anN
character in front of the literal string expression as required by SQL Server for Unicode string values rendered in SQL expressions.References: #4442
misc¶
1.3.0b1¶
Released: November 16, 2018orm¶
Added new feature
Query.only_return_tuples()
. Causes theQuery
object to return keyed tuple objects unconditionally even if the query is against a single entity. Pull request courtesy Eric Atkin.This change is also backported to: 1.2.5
Added new flag
Session.bulk_save_objects.preserve_order
to theSession.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.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
relationship.omit_join
flag to False. Many thanks to Jayson Reis for the efforts on this.References: #4340
Added
.info
dictionary to theInstanceState
class, the object that comes from callinginspect()
on a mapped object.References: #4257
Fixed bug where use of
Lateral
construct in conjunction withQuery.join()
as well asQuery.select_entity_from()
would not apply clause adaption to the right side of the join. “lateral” introduces the use case of the right side of a join being correlatable. Previously, adaptation of this clause wasn’t considered. Note that in 1.2 only, a selectable introduced byQuery.subquery()
is still not adapted due to #4304; the selectable needs to be produced by theselect()
function to be the right side of the “lateral” join.This change is also backported to: 1.2.12
References: #4334
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.
References: #3844
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
Session
, even if the attribute has been expired. New features within theInstanceState
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.References: #4359
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.
References: #4246
Refactored
Query.join()
to further clarify the individual components of structuring the join. This refactor adds the ability forQuery.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 #4363 but is also of general use. The codepaths withinQuery.join()
are now easier to follow and the error cases are decided more specifically at an earlier point in the operation.References: #4365
Fixed long-standing issue in
Query
where a scalar subquery such as produced byQuery.exists()
,Query.as_scalar()
and other derivations fromQuery.statement
would not correctly be adapted when used in a newQuery
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 theselect()
object produced by theQuery.statement
accessor.References: #4304
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 aTypeError
in this case. The flush process sorts persistent objects by primary key in Python so the values must be sortable.References: #4232
Removed the collection converter used by the
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 orAttributeEvents.bulk_replace()
listener that wants to convert incoming values further. TheTypeError
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
AttributeEvents.bulk_replace()
event handler added as part of #3896.References: #3604
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.References: #4353
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 asdel a.b
. This is now implemented and is equivalent to setting the attribute toNone
.See also
References: #4354
orm declarative¶
Fixed bug where declarative would not update the state of the
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. Additionally, aNotImplementedError
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.References: #4133
engine¶
Added new “lifo” mode to
QueuePool
, typically enabled by setting the flagcreate_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.
sql¶
Refactored
SQLCompiler
to expose aSQLCompiler.group_by_clause()
method similar to theSQLCompiler.order_by_clause()
andSQLCompiler.limit_clause()
methods, which can be overridden by dialects to customize how GROUP BY renders. Pull request courtesy Samuel Chou.This change is also backported to: 1.2.13
Added
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.References: #4144
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 thereferred_column_0_name
token would inadvertently render the.key
and not the.name
of the column if these two values were different.References: #3989
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.
References: #4271
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.Added new feature
FunctionElement.as_comparison()
which allows a SQL function to act as a binary comparison operation that can work within the ORM.References: #3831
Added “like” based operators as “comparison” operators, including
ColumnOperators.startswith()
ColumnOperators.endswith()
ColumnOperators.ilike()
ColumnOperators.notilike()
among many others, so that all of these operators can be the basis for an ORM “primaryjoin” condition.References: #4302
Fixed issue with
TypeEngine.bind_expression()
andTypeEngine.column_expression()
methods where these methods would not work if the target type were part of aVariant
, or other target type of aTypeDecorator
. 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.See also
TypeEngine methods bind_expression, column_expression work with Variant, type-specific types
References: #3981
postgresql¶
Added new PG type
REGCLASS
which assists in casting table names to OID values. Pull request courtesy Sebastian Bank.This change is also backported to: 1.2.7
References: #4160
Added rudimental support for reflection of PostgreSQL partitioned tables, e.g. that relkind=’p’ is added to reflection queries that return table information.
References: #4237
mysql¶
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 themysql_prefix
index option.References: #4219
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 Parameter-Ordered Updates. Pull request courtesy Maxim Bublis.
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.
sqlite¶
Added support for SQLite’s json functionality via the new SQLite implementation for
JSON
,JSON
. The name used for the type isJSON
, following an example found at SQLite’s own documentation. Pull request courtesy Ilja Everilä.See also
References: #3850
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 aColumn
to satisfy inline primary key and NOT NULL. Pull request courtesy Denis Kataev.References: #4360
mssql¶
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.See also
References: #4158
Deprecated the use of
Sequence
with SQL Server in order to affect the “start” and “increment” of the IDENTITY value, in favor of new parametersmssql_identity_start
andmssql_identity_increment
which set these parameters directly.Sequence
will be used to generate realCREATE SEQUENCE
DDL with SQL Server in a future release.References: #4362
oracle¶
Added a new event currently used only by the cx_Oracle dialect,
DialectEvents.setiputsizes()
. The event passes a dictionary ofBindParameter
objects to DBAPI-specific type objects that will be passed, after conversion to parameter names, to the cx_Oraclecursor.setinputsizes()
method. This allows both visibility into the setinputsizes process as well as the ability to alter the behavior of what datatypes are passed to this method.See also
cx_oracle_setinputsizes
This change is also backported to: 1.2.9
References: #4290
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.
References: #4369
The Oracle dialect will no longer use the NCHAR/NCLOB datatypes represent generic unicode strings or clob fields in conjunction with
Unicode
andUnicodeText
unless the flaguse_nchar_for_unicode=True
is passed tocreate_engine()
- this includes CREATE TABLE behavior as well assetinputsizes()
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.References: #4242
misc¶
Added new attribute
Query.lazy_loaded_from
which is populated with anInstanceState
that is using thisQuery
in order to lazy load a relationship. The rationale for this is that it serves as a hint for the horizontal sharding feature to use, such that the identity token of the state can be used as the default identity token to use for the query within id_chooser().This change is also backported to: 1.2.9
References: #4243
Added new feature
BakedQuery.to_query()
, which allows for a clean way of using oneBakedQuery
as a subquery inside of anotherBakedQuery
without needing to refer explicitly to aSession
.References: #4318
The
AssociationProxy
now has standard column comparison operations such asColumnOperators.like()
andColumnOperators.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 ofColumnOperators.contains()
when used on a column-based attribute.References: #4351
Added support for bulk
Query.update()
andQuery.delete()
to theShardedQuery
class within the horizontal sharding extension. This also adds an additional expansion hook to the bulk update/delete methodsQuery._execute_crud()
.References: #4196
Reworked
AssociationProxy
to store state that’s specific to a parent class in a separate object, so that a singleAssociationProxy
can serve for multiple parent classes, as is intrinsic to inheritance, without any ambiguity in the state returned by it. A new methodAssociationProxy.for_class()
is added to allow inspection of class-specific state.References: #3423
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.
See also
References: #4268
Fixed multiple issues regarding de-association of scalar objects with the association proxy.
del
now works, and additionally a new flagAssociationProxy.cascade_scalar_deletes
is added, which when set to True indicates that setting a scalar attribute toNone
or deleting viadel
will also set the source association toNone
.References: #4308