: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
pep-249 exception names linked to exception classes of an entirely different name, preventing SQLAlchemy's own exception wrapping from wrapping the error appropriately. The SQLAlchemy dialect in use needs to implement a new accessor :attr:`.DefaultDialect.dbapi_exception_translation_map` to support this feature; this is implemented now for the py-postgresql dialect. fixes #3421
fail to store the correct value for MSSQL on an INSERT where the primary key value was present in the insert params before execution. fixes #3360
That is, after exhausing all rows using the fetch methods, the DBAPI cursor is released as before and the object may be safely discarded, but the fetch methods may continue to be called for which they will return an end-of-result object (None for fetchone, empty list for fetchmany and fetchall). Only if :meth:`.ResultProxy.close` is called explicitly will these methods raise the "result is closed" error. fixes #3330 fixes #3329
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.
such that they are matched to the received result set positionally, rather than by name. Originally, this was seen as a way to handle cases where we had columns returned with difficult-to-predict names, though in modern use that issue has been overcome by anonymous labeling. In this version, the approach basically reduces function call count per-result by a few dozen calls, or more for larger sets of result columns. The approach still degrades into a modern version of the old approach if textual elements modify the result map, or if any discrepancy in size exists between the compiled set of columns versus what was received, so there's no issue for partially or fully textual compilation scenarios where these lists might not line up. fixes #918 - callcounts still need to be adjusted down for this so zoomark tests won't pass at the moment
with :meth:`.Connection.execution_options` when a :class:`.Transaction` is in play; DBAPIs and/or SQLAlchemy dialects such as psycopg2, MySQLdb may implicitly rollback or commit the transaction, or not change the setting til next transaction, so this is never safe. - Added new parameter :paramref:`.Session.connection.execution_options` which may be used to set up execution options on a :class:`.Connection` when it is first checked out, before the transaction has begun. This is used to set up options such as isolation level on the connection before the transaction starts. - added new documentation section detailing best practices for setting transaction isolation with sessions. fixes #3296
logic to some degree in DefaultExecutionContext. In particular we are removing post_insert() which doesn't appear to be used based on a survey of prominent third party dialects. Callcounts aren't added to existing execute profiling tests and inserts might be a little better. - simplify the execution_options join in DEC. Callcounts don't appear affected.