1.3.6

Released: July 21, 2019

• [bug] [engine] Fixed bug where using reflection function such as MetaData.reflect()
  with an Engine object that had execution options applied to it
  would fail, as the resulting OptionEngine proxy object failed to
  include a .engine attribute used within the reflection routines.

  References: #4754

• [bug] [mysql] Fixed bug where the special logic to render "NULL" for the
  TIMESTAMP datatype when nullable=True would not work if the
  column's datatype were a TypeDecorator or a Variant.
  The logic now ensures that it unwraps down to the original
  TIMESTAMP so that this special case NULL keyword is correctly
  rendered when requested.

  References: #4743

• [orm] [performance] 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

• [bug] [orm] 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

• [feature] [orm] 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 call defaultload()
  many times. Thanks to Alessio Bogon for the idea.

  References: #4736

• [postgresql] [usecase] Added support for reflection of indexes on PostgreSQL partitioned tables,
  which was added to PostgreSQL as of version 11.

  References: #4771

• [bug] [mysql] 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

• [bug] [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 against sys.
  tables.

  References: #4745

• [bug] [orm] Fixed an issue where the orm._ORMJoin.join() method, which is a
  not-internally-used ORM-level method that exposes what is normally an
  internal process of Query.join(), did not propagate the full and
  outerjoin keyword arguments correctly. Pull request courtesy Denis
  Kataev.

  References: #4713

• [bug] [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

• [bug] [orm] 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

• [bug] [orm] 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

• [bug] [orm] 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

• [postgresql] [usecase] Added support for multidimensional Postgresql array literals via nesting
  the postgresql.array object within another one. The
  multidimensional array type is detected automatically.

  References: #4756

• [bug] [postgresql] [sql] Fixed issue where the array_agg construct in combination with
  FunctionElement.filter() would not produce the correct operator
  precedence in combination with the array index operator.

  References: #4760

• [bug] [sql] Fixed an unlikely issue where the "corresponding column" routine for unions
  and other CompoundSelect objects could return the wrong column in
  some overlapping column situtations, thus potentially impacting some ORM
  operations when set operations are in use, if the underlying
  select() constructs were used previously in other similar kinds of
  routines, due to a cached value not being cleared.

  References: #4747

• [sqlite] [usecase] 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