Released: November 11, 2019
[orm] [usecase] Added accessor
will indicate if the results returned by this
Querywill 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.
[orm] [bug] The
relationship.omit_joinflag 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 the
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.
[orm] [bug] A warning is emitted if a primary key value is passed to
that consists of None for all primary key column positions. Previously,
passing a single None outside of a tuple would raise a
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.
[orm] [bug] The
BakedQuerywill not cache a query that was modified by a
QueryEvents.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
bake_okis added; see
A longer term plan to provide a new form of SQL caching should solve this
kind of issue more comprehensively.
[orm] [bug] 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
joinedload(), were generated. The
"local" side is now excluded.
[engine] [bug] 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.
[engine] [bug] [postgresql] Fixed bug in
Inspectorwhere 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.
[sql] [bug] [py3k] Changed the
quoted_nameconstruct to use
regular string repr() under Python 3, rather than running it through
"backslashreplace" escaping, which can be misleading.
[sql] [usecase] Added new accessors to expressions of type
JSONto 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.
[sql] [usecase] The
text()construct now supports "unique" bound parameters, which
will dynamically uniquify themselves on compilation thus allowing multiple
text()constructs with the same bound parameter names to be combined
[schema] [bug] 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
._labelattribute for a column before this overlap could
be detected due to the use of the
the column in conjunction with the default naming convention of
"column_0_label". This would then lead to failures when
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
._labelaccessor for DDL
generation that does not affect the state of the
accessor also bypasses the key-deduplication step as it is not necessary
for DDL, the naming is now consistently
without any subsequent numeric symbols when used in DDL.
[schema] [usecase] 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.
[mysql] [bug] 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.
[mssql] [bug] 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.
[mssql] [bug] 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 the
MetaData.reflect()function so is a prominent codepath. In 1.4,
which is the current master development branch, this issue doesn't exist,
MetaData.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().
[oracle] [bug] [firebird] 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_nameconstruct 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 to
quoted_nameobjects in any case; the change
here would only affect the output of some inspection functions.
[oracle] [usecase] Added dialect-level flag
encoding_errorsto the cx_Oracle dialect,
which can be specified as part of
create_engine(). This is passed
to SQLAlchemy's unicode decoding converter under Python 2, and to
cursor.var()object as the
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 to
[oracle] [bug] The
sqltypes.NCHARdatatype will now bind to the
cx_Oracle.FIXED_NCHARDBAPI data bindings when used in a bound
parameter, which supplies proper comparison behavior against a
variable-length string. Previously, the
would bind to
cx_oracle.NCHARwhich is not fixed length; the
sqltypes.CHARdatatype already binds to
so it is now consistent that
[firebird] [bug] Added additional "disconnect" message "Error writing data to the
connection" to Firebird disconnection detection. Pull request courtesy
[bug] [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.
[bug] [installation] [windows] 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