returns an invalid date or time format from a DATE or TIME
column, rather than failing with a NoneType error. Pull request
courtesy Ed Avis.
pullreq github:206
as part of 🎫`3424` to allow disabling of the MSSQL dialect's
attempts to create aliases for schema-qualified tables, now defaults
to False; the old behavior is now disabled unless explicitly turned on.
fixes#3434
- new test for json col['x']['y']['z'] seems to fail pre PG 9.4,
fails on comparisons for non-compatible data instead of not matching
- no need to call SpecPredicate(db) directly in exclusion functions,
by using Predicate.as_predicate() the spec strings can have version
comparisons
or other variable-length column type with unbounded length
by assigning the token ``"max"`` to the
length attribute of the string. While using the ``"max"`` token
explicitly is supported by the SQL Server dialect, it isn't part
of the normal contract of the base string types, and instead the
length should just be left as None. The dialect now assigns the
length to None on reflection of the type so that the type behaves
normally in other contexts.
fixes#3504
an INSERT of NULL + pyodbc; pyodbc requires a special
object be passed in order to persist NULL. As the :class:`.VARBINARY`
type is now usually the default for :class:`.LargeBinary` due to
🎫`3039`, this issue is partially a regression in 1.0.
The pymssql driver appears to be unaffected.
fixes#3464
:func:`.engine_from_config` were not being parsed correctly;
these included ``pool_threadlocal`` and the psycopg2 argument
``use_native_unicode``. fixes#3435
- add legacy_schema_aliasing config parsing for mssql
- move use_native_unicode config arg to the psycopg2 dialect
``legacy_schema_aliasing`` which when set to False will disable a
very old and obsolete behavior, that of the compiler's
attempt to turn all schema-qualified table names into alias names,
to work around old and no longer locatable issues where SQL
server could not parse a multi-part identifier name in all
circumstances. The behavior prevented more
sophisticated statements from working correctly, including those which
use hints, as well as CRUD statements that embed correlated SELECT
statements. Rather than continue to repair the feature to work
with more complex statements, it's better to just disable it
as it should no longer be needed for any modern SQL server
version. The flag defaults to True for the 1.0.x series, leaving
current behavior unchanged for this version series. In the 1.1
series, it will default to False. For the 1.0 series,
when not set to either value explicitly, a warning is emitted
when a schema-qualified table is first used in a statement, which
suggests that the flag be set to False for all modern SQL Server
versions.
fixes#3424fixes#3430
The "wrapping" employed by the mssql and oracle dialects using the
"iswrapper" argument was not being used intelligently by the compiler,
and the result map was being written incorrectly, using
*more* columns in the result map than were actually returned by
the statement, due to "row number" columns that are inside the
subquery. The compiler now writes out result map on the
"top level" select in all cases
fully, and for the mssql/oracle wrapping case extracts out
the "proxied" columns in a second step, which only includes
those columns that are proxied outwards to the top level.
This change might have implications for 3rd party dialects that
might be imitating oracle's approach. They can safely continue
to use the "iswrapper" kw which is now ignored, but they may
need to also add the _select_wraps argument as well.
VARBINARY(max) for large text/binary types. The MSSQL dialect will
now respect this based on version detection, as well as the new
``deprecate_large_types`` flag.
fixes#3039
anonymous bound parameter names within expressions, to match the
existing use of this value as the key when rendered in an INSERT
or UPDATE statement. This allows :attr:`.Column.key` to be used
as a "substitute" string to work around a difficult column name
that doesn't translate well into a bound parameter name. Note that
the paramstyle is configurable on :func:`.create_engine` in any case,
and most DBAPIs today support a named and positional style.
fixes#3245
pyodbc will no longer specify a default "driver name", and a warning
is emitted if this is missing. The optimal driver name for SQL Server
changes frequently and is per-platform, so hostname based connections
need to specify this. DSN-based connections are preferred.
fixes#3182
In pymssql, if you terminate a long running query manually
it will give you a connection reset by peer message, but this
connection remains in the pool and will be re-used.
mssql to ensure that any literal SQL expression values are
rendered directly as literals, instead of as bound parameters,
within a CREATE INDEX statement. [ticket:2742]
- don't need expression_as_ddl(); literal_binds and include_table
take care of this functionality.
Mike Bayer