a label that was anonymous, then labeled again with a name, would fail to be locatable via a textual label. This situation occurs naturally when a mapped :func:`.column_property` is given an explicit label in a query. fixes #3340
- replace force_result_map with a mini-API for nested result sets, add coverage
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
when using the :paramref:`.Column.server_default` parameter, will now be rendered using the "inline" compiler, so that they are rendered as-is, rather than as bound parameters. fixes #3087
now be constructed such that the visit methods receive an indication of the owning expression object, if any. Any visit method that accepts keyword arguments (e.g. ``**kw``) will in most cases receive a keyword argument ``type_expression``, referring to the expression object that the type is contained within. For columns in DDL, the dialect's compiler class may need to alter its ``get_column_specification()`` method to support this as well. The ``UserDefinedType.get_col_spec()`` method will also receive ``type_expression`` if it provides ``**kw`` in its argument signature. fixes #3074
sort_tables_and_constraints function. - The DDL generation system of :meth:`.MetaData.create_all` and :meth:`.Metadata.drop_all` has been enhanced to in most cases automatically handle the case of mutually dependent foreign key constraints; the need for the :paramref:`.ForeignKeyConstraint.use_alter` flag is greatly reduced. The system also works for constraints which aren't given a name up front; only in the case of DROP is a name required for at least one of the constraints involved in the cycle. fixes #3282
to the aliasing syntax, as well as a new CTE feature :meth:`.CTE.suffix_with`, which is useful for adding in special Oracle-specific directives to the CTE. fixes #3220