From d6ce68727f8ad4c77cc64ac6bbc5fc17ecd2b8e3 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 25 Aug 2013 14:03:54 -0400 Subject: - The ``version_id_generator`` parameter of ``Mapper`` can now be specified to rely upon server generated version identifiers, using triggers or other database-provided versioning features, by passing the value ``False``. The ORM will use RETURNING when available to immediately load the new version identifier, else it will emit a second SELECT. [ticket:2793] - The ``eager_defaults`` flag of :class:`.Mapper` will now allow the newly generated default values to be fetched using an inline RETURNING clause, rather than a second SELECT statement, for backends that support RETURNING. - Added a new variant to :meth:`.ValuesBase.returning` called :meth:`.ValuesBase.return_defaults`; this allows arbitrary columns to be added to the RETURNING clause of the statement without interfering with the compilers usual "implicit returning" feature, which is used to efficiently fetch newly generated primary key values. For supporting backends, a dictionary of all fetched values is present at :attr:`.ResultProxy.returned_defaults`. - add a glossary entry for RETURNING - add documentation for version id generation, [ticket:867] --- lib/sqlalchemy/engine/base.py | 6 ++++++ lib/sqlalchemy/engine/default.py | 7 +++++++ lib/sqlalchemy/engine/result.py | 10 ++++++++++ 3 files changed, 23 insertions(+) (limited to 'lib/sqlalchemy/engine') diff --git a/lib/sqlalchemy/engine/base.py b/lib/sqlalchemy/engine/base.py index 83fa34f2c..257eaa18a 100644 --- a/lib/sqlalchemy/engine/base.py +++ b/lib/sqlalchemy/engine/base.py @@ -898,6 +898,12 @@ class Connection(Connectable): elif not context._is_explicit_returning: result.close(_autoclose_connection=False) result._metadata = None + elif context.isupdate: + if context._is_implicit_returning: + context._fetch_implicit_update_returning(result) + result.close(_autoclose_connection=False) + result._metadata = None + elif result._metadata is None: # no results, get rowcount # (which requires open cursor on some drivers diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py index 017dfa902..90c7f5993 100644 --- a/lib/sqlalchemy/engine/default.py +++ b/lib/sqlalchemy/engine/default.py @@ -396,6 +396,7 @@ class DefaultExecutionContext(interfaces.ExecutionContext): statement = None postfetch_cols = None prefetch_cols = None + returning_cols = None _is_implicit_returning = False _is_explicit_returning = False @@ -492,6 +493,7 @@ class DefaultExecutionContext(interfaces.ExecutionContext): if self.isinsert or self.isupdate: self.postfetch_cols = self.compiled.postfetch self.prefetch_cols = self.compiled.prefetch + self.returning_cols = self.compiled.returning self.__process_defaults() processors = compiled._bind_processors @@ -750,6 +752,11 @@ class DefaultExecutionContext(interfaces.ExecutionContext): ipk.append(row[c]) self.inserted_primary_key = ipk + self.returned_defaults = row + + def _fetch_implicit_update_returning(self, resultproxy): + row = resultproxy.fetchone() + self.returned_defaults = row def lastrow_has_defaults(self): return (self.isinsert or self.isupdate) and \ diff --git a/lib/sqlalchemy/engine/result.py b/lib/sqlalchemy/engine/result.py index 91f3c2275..0e2316573 100644 --- a/lib/sqlalchemy/engine/result.py +++ b/lib/sqlalchemy/engine/result.py @@ -621,6 +621,16 @@ class ResultProxy(object): else: return self.context.compiled_parameters[0] + @property + def returned_defaults(self): + """Return the values of default columns that were fetched using + the ``returned_defaults`` feature. + + .. versionadded:: 0.9.0 + + """ + return self.context.returned_defaults + def lastrow_has_defaults(self): """Return ``lastrow_has_defaults()`` from the underlying :class:`.ExecutionContext`. -- cgit v1.2.1