diff options
Diffstat (limited to 'lib/sqlalchemy/orm/query.py')
| -rw-r--r-- | lib/sqlalchemy/orm/query.py | 284 |
1 files changed, 185 insertions, 99 deletions
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py index 790686288..60a637952 100644 --- a/lib/sqlalchemy/orm/query.py +++ b/lib/sqlalchemy/orm/query.py @@ -75,6 +75,7 @@ class Query(object): _having = None _distinct = False _prefixes = None + _suffixes = None _offset = None _limit = None _for_update_arg = None @@ -159,7 +160,6 @@ class Query(object): for from_obj in obj: info = inspect(from_obj) - if hasattr(info, 'mapper') and \ (info.is_mapper or info.is_aliased_class): self._select_from_entity = from_obj @@ -285,8 +285,9 @@ class Query(object): return self._entities[0] def _mapper_zero(self): - return self._select_from_entity or \ - self._entity_zero().entity_zero + return self._select_from_entity \ + if self._select_from_entity is not None \ + else self._entity_zero().entity_zero @property def _mapper_entities(self): @@ -300,11 +301,14 @@ class Query(object): self._mapper_zero() ) - def _mapper_zero_or_none(self): - if self._primary_entity: - return self._primary_entity.mapper - else: - return None + def _bind_mapper(self): + ezero = self._mapper_zero() + if ezero is not None: + insp = inspect(ezero) + if hasattr(insp, 'mapper'): + return insp.mapper + + return None def _only_mapper_zero(self, rationale=None): if len(self._entities) > 1: @@ -810,7 +814,7 @@ class Query(object): foreign-key-to-primary-key criterion, will also use an operation equivalent to :meth:`~.Query.get` in order to retrieve the target value from the local identity map - before querying the database. See :doc:`/orm/loading` + before querying the database. See :doc:`/orm/loading_relationships` for further details on relationship loading. :param ident: A scalar or tuple value representing @@ -987,6 +991,7 @@ class Query(object): statement.correlate(None) q = self._from_selectable(fromclause) q._enable_single_crit = False + q._select_from_entity = self._mapper_zero() if entities: q._set_entities(entities) return q @@ -1003,7 +1008,7 @@ class Query(object): '_limit', '_offset', '_joinpath', '_joinpoint', '_distinct', '_having', - '_prefixes', + '_prefixes', '_suffixes' ): self.__dict__.pop(attr, None) self._set_select_from([fromclause], True) @@ -1099,7 +1104,7 @@ class Query(object): Most supplied options regard changing how column- and relationship-mapped attributes are loaded. See the sections - :ref:`deferred` and :doc:`/orm/loading` for reference + :ref:`deferred` and :doc:`/orm/loading_relationships` for reference documentation. """ @@ -2359,12 +2364,38 @@ class Query(object): .. versionadded:: 0.7.7 + .. seealso:: + + :meth:`.HasPrefixes.prefix_with` + """ if self._prefixes: self._prefixes += prefixes else: self._prefixes = prefixes + @_generative() + def suffix_with(self, *suffixes): + """Apply the suffix to the query and return the newly resulting + ``Query``. + + :param \*suffixes: optional suffixes, typically strings, + not using any commas. + + .. versionadded:: 1.0.0 + + .. seealso:: + + :meth:`.Query.prefix_with` + + :meth:`.HasSuffixes.suffix_with` + + """ + if self._suffixes: + self._suffixes += suffixes + else: + self._suffixes = suffixes + def all(self): """Return the results represented by this ``Query`` as a list. @@ -2499,7 +2530,7 @@ class Query(object): def _execute_and_instances(self, querycontext): conn = self._connection_from_session( - mapper=self._mapper_zero_or_none(), + mapper=self._bind_mapper(), clause=querycontext.statement, close_with_result=True) @@ -2601,6 +2632,7 @@ class Query(object): 'offset': self._offset, 'distinct': self._distinct, 'prefixes': self._prefixes, + 'suffixes': self._suffixes, 'group_by': self._group_by or None, 'having': self._having } @@ -2697,6 +2729,18 @@ class Query(object): Deletes rows matched by this query from the database. + E.g.:: + + sess.query(User).filter(User.age == 25).\\ + delete(synchronize_session=False) + + sess.query(User).filter(User.age == 25).\\ + delete(synchronize_session='evaluate') + + .. warning:: The :meth:`.Query.delete` method is a "bulk" operation, + which bypasses ORM unit-of-work automation in favor of greater + performance. **Please read all caveats and warnings below.** + :param synchronize_session: chooses the strategy for the removal of matched objects from the session. Valid values are: @@ -2715,8 +2759,7 @@ class Query(object): ``'evaluate'`` - Evaluate the query's criteria in Python straight on the objects in the session. If evaluation of the criteria isn't - implemented, an error is raised. In that case you probably - want to use the 'fetch' strategy as a fallback. + implemented, an error is raised. The expression evaluator currently doesn't account for differing string collations between the database and Python. @@ -2724,29 +2767,42 @@ class Query(object): :return: the count of rows matched as returned by the database's "row count" feature. - This method has several key caveats: - - * The method does **not** offer in-Python cascading of relationships - - it is assumed that ON DELETE CASCADE/SET NULL/etc. is configured - for any foreign key references which require it, otherwise the - database may emit an integrity violation if foreign key references - are being enforced. - - After the DELETE, dependent objects in the :class:`.Session` which - were impacted by an ON DELETE may not contain the current - state, or may have been deleted. This issue is resolved once the - :class:`.Session` is expired, - which normally occurs upon :meth:`.Session.commit` or can be forced - by using :meth:`.Session.expire_all`. Accessing an expired object - whose row has been deleted will invoke a SELECT to locate the - row; when the row is not found, an - :class:`~sqlalchemy.orm.exc.ObjectDeletedError` is raised. - - * The :meth:`.MapperEvents.before_delete` and - :meth:`.MapperEvents.after_delete` - events are **not** invoked from this method. Instead, the - :meth:`.SessionEvents.after_bulk_delete` method is provided to act - upon a mass DELETE of entity rows. + .. warning:: **Additional Caveats for bulk query deletes** + + * The method does **not** offer in-Python cascading of + relationships - it is assumed that ON DELETE CASCADE/SET + NULL/etc. is configured for any foreign key references + which require it, otherwise the database may emit an + integrity violation if foreign key references are being + enforced. + + After the DELETE, dependent objects in the + :class:`.Session` which were impacted by an ON DELETE + may not contain the current state, or may have been + deleted. This issue is resolved once the + :class:`.Session` is expired, which normally occurs upon + :meth:`.Session.commit` or can be forced by using + :meth:`.Session.expire_all`. Accessing an expired + object whose row has been deleted will invoke a SELECT + to locate the row; when the row is not found, an + :class:`~sqlalchemy.orm.exc.ObjectDeletedError` is + raised. + + * The ``'fetch'`` strategy results in an additional + SELECT statement emitted and will significantly reduce + performance. + + * The ``'evaluate'`` strategy performs a scan of + all matching objects within the :class:`.Session`; if the + contents of the :class:`.Session` are expired, such as + via a proceeding :meth:`.Session.commit` call, **this will + result in SELECT queries emitted for every matching object**. + + * The :meth:`.MapperEvents.before_delete` and + :meth:`.MapperEvents.after_delete` + events **are not invoked** from this method. Instead, the + :meth:`.SessionEvents.after_bulk_delete` method is provided to + act upon a mass DELETE of entity rows. .. seealso:: @@ -2769,17 +2825,21 @@ class Query(object): E.g.:: - sess.query(User).filter(User.age == 25).\ - update({User.age: User.age - 10}, synchronize_session='fetch') - + sess.query(User).filter(User.age == 25).\\ + update({User.age: User.age - 10}, synchronize_session=False) - sess.query(User).filter(User.age == 25).\ + sess.query(User).filter(User.age == 25).\\ update({"age": User.age - 10}, synchronize_session='evaluate') + .. warning:: The :meth:`.Query.update` method is a "bulk" operation, + which bypasses ORM unit-of-work automation in favor of greater + performance. **Please read all caveats and warnings below.** + + :param values: a dictionary with attributes names, or alternatively - mapped attributes or SQL expressions, as keys, and literal - values or sql expressions as values. + mapped attributes or SQL expressions, as keys, and literal + values or sql expressions as values. .. versionchanged:: 1.0.0 - string names in the values dictionary are now resolved against the mapped entity; previously, these @@ -2787,7 +2847,7 @@ class Query(object): translation. :param synchronize_session: chooses the strategy to update the - attributes on objects in the session. Valid values are: + attributes on objects in the session. Valid values are: ``False`` - don't synchronize the session. This option is the most efficient and is reliable once the session is expired, which @@ -2808,43 +2868,56 @@ class Query(object): string collations between the database and Python. :return: the count of rows matched as returned by the database's - "row count" feature. - - This method has several key caveats: - - * The method does **not** offer in-Python cascading of relationships - - it is assumed that ON UPDATE CASCADE is configured for any foreign - key references which require it, otherwise the database may emit an - integrity violation if foreign key references are being enforced. - - After the UPDATE, dependent objects in the :class:`.Session` which - were impacted by an ON UPDATE CASCADE may not contain the current - state; this issue is resolved once the :class:`.Session` is expired, - which normally occurs upon :meth:`.Session.commit` or can be forced - by using :meth:`.Session.expire_all`. - - * The method supports multiple table updates, as - detailed in :ref:`multi_table_updates`, and this behavior does - extend to support updates of joined-inheritance and other multiple - table mappings. However, the **join condition of an inheritance - mapper is currently not automatically rendered**. - Care must be taken in any multiple-table update to explicitly - include the joining condition between those tables, even in mappings - where this is normally automatic. - E.g. if a class ``Engineer`` subclasses ``Employee``, an UPDATE of - the ``Engineer`` local table using criteria against the ``Employee`` - local table might look like:: - - session.query(Engineer).\\ - filter(Engineer.id == Employee.id).\\ - filter(Employee.name == 'dilbert').\\ - update({"engineer_type": "programmer"}) - - * The :meth:`.MapperEvents.before_update` and - :meth:`.MapperEvents.after_update` - events are **not** invoked from this method. Instead, the - :meth:`.SessionEvents.after_bulk_update` method is provided to act - upon a mass UPDATE of entity rows. + "row count" feature. + + .. warning:: **Additional Caveats for bulk query updates** + + * The method does **not** offer in-Python cascading of + relationships - it is assumed that ON UPDATE CASCADE is + configured for any foreign key references which require + it, otherwise the database may emit an integrity + violation if foreign key references are being enforced. + + After the UPDATE, dependent objects in the + :class:`.Session` which were impacted by an ON UPDATE + CASCADE may not contain the current state; this issue is + resolved once the :class:`.Session` is expired, which + normally occurs upon :meth:`.Session.commit` or can be + forced by using :meth:`.Session.expire_all`. + + * The ``'fetch'`` strategy results in an additional + SELECT statement emitted and will significantly reduce + performance. + + * The ``'evaluate'`` strategy performs a scan of + all matching objects within the :class:`.Session`; if the + contents of the :class:`.Session` are expired, such as + via a proceeding :meth:`.Session.commit` call, **this will + result in SELECT queries emitted for every matching object**. + + * The method supports multiple table updates, as detailed + in :ref:`multi_table_updates`, and this behavior does + extend to support updates of joined-inheritance and + other multiple table mappings. However, the **join + condition of an inheritance mapper is not + automatically rendered**. Care must be taken in any + multiple-table update to explicitly include the joining + condition between those tables, even in mappings where + this is normally automatic. E.g. if a class ``Engineer`` + subclasses ``Employee``, an UPDATE of the ``Engineer`` + local table using criteria against the ``Employee`` + local table might look like:: + + session.query(Engineer).\\ + filter(Engineer.id == Employee.id).\\ + filter(Employee.name == 'dilbert').\\ + update({"engineer_type": "programmer"}) + + * The :meth:`.MapperEvents.before_update` and + :meth:`.MapperEvents.after_update` + events **are not invoked from this method**. Instead, the + :meth:`.SessionEvents.after_bulk_update` method is provided to + act upon a mass UPDATE of entity rows. .. seealso:: @@ -3473,26 +3546,26 @@ class _ColumnEntity(_QueryEntity): )): self._label_name = column.key column = column._query_clause_element() - else: - self._label_name = getattr(column, 'key', None) - - if not isinstance(column, expression.ColumnElement) and \ - hasattr(column, '_select_iterable'): - for c in column._select_iterable: - if c is column: - break - _ColumnEntity(query, c, namespace=column) - else: + if isinstance(column, Bundle): + _BundleEntity(query, column) return - elif isinstance(column, Bundle): - _BundleEntity(query, column) - return + elif not isinstance(column, sql.ColumnElement): + if hasattr(column, '_select_iterable'): + # break out an object like Table into + # individual columns + for c in column._select_iterable: + if c is column: + break + _ColumnEntity(query, c, namespace=column) + else: + return - if not isinstance(column, sql.ColumnElement): raise sa_exc.InvalidRequestError( "SQL expression, column, or mapped entity " "expected - got '%r'" % (column, ) ) + else: + self._label_name = getattr(column, 'key', None) self.type = type_ = column.type if type_.hashable: @@ -3523,15 +3596,26 @@ class _ColumnEntity(_QueryEntity): # leaking out their entities into the main select construct self.actual_froms = actual_froms = set(column._from_objects) - self.entities = util.OrderedSet( + all_elements = [ + elem for elem in visitors.iterate(column, {}) + if 'parententity' in elem._annotations + ] + + self.entities = util.unique_list( + elem._annotations['parententity'] + for elem in all_elements + if 'parententity' in elem._annotations + ) + + self._from_entities = set( elem._annotations['parententity'] - for elem in visitors.iterate(column, {}) + for elem in all_elements if 'parententity' in elem._annotations and actual_froms.intersection(elem._from_objects) ) if self.entities: - self.entity_zero = list(self.entities)[0] + self.entity_zero = self.entities[0] elif self.namespace is not None: self.entity_zero = self.namespace else: @@ -3557,7 +3641,9 @@ class _ColumnEntity(_QueryEntity): def setup_entity(self, ext_info, aliased_adapter): if 'selectable' not in self.__dict__: self.selectable = ext_info.selectable - self.froms.add(ext_info.selectable) + + if self.actual_froms.intersection(ext_info.selectable._from_objects): + self.froms.add(ext_info.selectable) def corresponds_to(self, entity): # TODO: just returning False here, |