diff options
Diffstat (limited to 'lib/sqlalchemy/orm/query.py')
| -rw-r--r-- | lib/sqlalchemy/orm/query.py | 81 |
1 files changed, 65 insertions, 16 deletions
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py index 60948293b..f07060825 100644 --- a/lib/sqlalchemy/orm/query.py +++ b/lib/sqlalchemy/orm/query.py @@ -1145,7 +1145,8 @@ class Query(object): @_generative() def with_hint(self, selectable, text, dialect_name='*'): - """Add an indexing hint for the given entity or selectable to + """Add an indexing or other executional context + hint for the given entity or selectable to this :class:`.Query`. Functionality is passed straight through to @@ -1153,11 +1154,35 @@ class Query(object): with the addition that ``selectable`` can be a :class:`.Table`, :class:`.Alias`, or ORM entity / mapped class /etc. + + .. seealso:: + + :meth:`.Query.with_statement_hint` + """ - selectable = inspect(selectable).selectable + if selectable is not None: + selectable = inspect(selectable).selectable self._with_hints += ((selectable, text, dialect_name),) + def with_statement_hint(self, text, dialect_name='*'): + """add a statement hint to this :class:`.Select`. + + This method is similar to :meth:`.Select.with_hint` except that + it does not require an individual table, and instead applies to the + statement as a whole. + + This feature calls down into :meth:`.Select.with_statement_hint`. + + .. versionadded:: 1.0.0 + + .. seealso:: + + :meth:`.Query.with_hint` + + """ + return self.with_hint(None, text, dialect_name) + @_generative() def execution_options(self, **kwargs): """ Set non-SQL options which take effect during execution. @@ -1810,6 +1835,11 @@ class Query(object): left_entity = prop = None + if isinstance(onclause, interfaces.PropComparator): + of_type = getattr(onclause, '_of_type', None) + else: + of_type = None + if isinstance(onclause, util.string_types): left_entity = self._joinpoint_zero() @@ -1836,8 +1866,6 @@ class Query(object): if isinstance(onclause, interfaces.PropComparator): if right_entity is None: - right_entity = onclause.property.mapper - of_type = getattr(onclause, '_of_type', None) if of_type: right_entity = of_type else: @@ -1919,11 +1947,9 @@ class Query(object): from_obj, r_info.selectable): overlap = True break - elif sql_util.selectables_overlap(l_info.selectable, - r_info.selectable): - overlap = True - if overlap and l_info.selectable is r_info.selectable: + if (overlap or not create_aliases) and \ + l_info.selectable is r_info.selectable: raise sa_exc.InvalidRequestError( "Can't join table/selectable '%s' to itself" % l_info.selectable) @@ -2591,6 +2617,19 @@ class Query(object): SELECT 1 FROM users WHERE users.name = :name_1 ) AS anon_1 + The EXISTS construct is usually used in the WHERE clause:: + + session.query(User.id).filter(q.exists()).scalar() + + Note that some databases such as SQL Server don't allow an + EXISTS expression to be present in the columns clause of a + SELECT. To select a simple boolean value based on the exists + as a WHERE, use :func:`.literal`:: + + from sqlalchemy import literal + + session.query(literal(True)).filter(q.exists()).scalar() + .. versionadded:: 0.8.1 """ @@ -2718,9 +2757,25 @@ class Query(object): Updates rows matched by this query in the database. - :param values: a dictionary with attributes names as keys and literal + 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({"age": User.age - 10}, synchronize_session='evaluate') + + + :param values: a dictionary with attributes names, or alternatively + 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 + strings were passed as literal column names with no mapper-level + translation. + :param synchronize_session: chooses the strategy to update the attributes on objects in the session. Valid values are: @@ -2758,7 +2813,7 @@ class Query(object): which normally occurs upon :meth:`.Session.commit` or can be forced by using :meth:`.Session.expire_all`. - * As of 0.8, this method will support multiple table updates, as + * 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 @@ -2789,12 +2844,6 @@ class Query(object): """ - # TODO: value keys need to be mapped to corresponding sql cols and - # instr.attr.s to string keys - # TODO: updates of manytoone relationships need to be converted to - # fk assignments - # TODO: cascades need handling. - update_op = persistence.BulkUpdate.factory( self, synchronize_session, values) update_op.exec_() |