# orm/query.py # Copyright (C) 2005, 2006, 2007, 2008, 2009 Michael Bayer mike_mp@zzzcomputing.com # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """The Query class and support. Defines the :class:`~sqlalchemy.orm.query.Query` class, the central construct used by the ORM to construct database queries. The ``Query`` class should not be confused with the :class:`~sqlalchemy.sql.expression.Select` class, which defines database SELECT operations at the SQL (non-ORM) level. ``Query`` differs from ``Select`` in that it returns ORM-mapped objects and interacts with an ORM session, whereas the ``Select`` construct interacts directly with the database to return iterable result sets. """ from itertools import chain from operator import itemgetter from sqlalchemy import sql, util, log, schema from sqlalchemy import exc as sa_exc from sqlalchemy.orm import exc as orm_exc from sqlalchemy.sql import util as sql_util from sqlalchemy.sql import expression, visitors, operators from sqlalchemy.orm import ( attributes, interfaces, mapper, object_mapper, evaluator, ) from sqlalchemy.orm.util import ( AliasedClass, ORMAdapter, _entity_descriptor, _entity_info, _is_aliased_class, _is_mapped_class, _orm_columns, _orm_selectable, join as orm_join, ) __all__ = ['Query', 'QueryContext', 'aliased'] aliased = AliasedClass def _generative(*assertions): """Mark a method as generative.""" @util.decorator def generate(fn, *args, **kw): self = args[0]._clone() for assertion in assertions: assertion(self, fn.func_name) fn(self, *args[1:], **kw) return self return generate class Query(object): """Encapsulates the object-fetching operations provided by Mappers.""" def __init__(self, entities, session=None): self.session = session self._with_options = [] self._lockmode = None self._order_by = False self._group_by = False self._distinct = False self._offset = None self._limit = None self._statement = None self._params = {} self._yield_per = None self._criterion = None self._correlate = set() self._joinpoint = None self._with_labels = False self._enable_eagerloads = True self.__joinable_tables = None self._having = None self._populate_existing = False self._version_check = False self._autoflush = True self._attributes = {} self._current_path = () self._only_load_props = None self._refresh_state = None self._from_obj = () self._polymorphic_adapters = {} self._filter_aliases = None self._from_obj_alias = None self.__currenttables = set() self._set_entities(entities) def _set_entities(self, entities, entity_wrapper=None): if entity_wrapper is None: entity_wrapper = _QueryEntity self._entities = [] for ent in util.to_list(entities): entity_wrapper(self, ent) self.__setup_aliasizers(self._entities) def __setup_aliasizers(self, entities): if hasattr(self, '_mapper_adapter_map'): # usually safe to share a single map, but copying to prevent # subtle leaks if end-user is reusing base query with arbitrary # number of aliased() objects self._mapper_adapter_map = d = self._mapper_adapter_map.copy() else: self._mapper_adapter_map = d = {} for ent in entities: for entity in ent.entities: if entity not in d: mapper, selectable, is_aliased_class = _entity_info(entity) if not is_aliased_class and mapper.with_polymorphic: with_polymorphic = mapper._with_polymorphic_mappers self.__mapper_loads_polymorphically_with(mapper, sql_util.ColumnAdapter(selectable, mapper._equivalent_columns)) adapter = None elif is_aliased_class: adapter = sql_util.ColumnAdapter(selectable, mapper._equivalent_columns) with_polymorphic = None else: with_polymorphic = adapter = None d[entity] = (mapper, adapter, selectable, is_aliased_class, with_polymorphic) ent.setup_entity(entity, *d[entity]) def __mapper_loads_polymorphically_with(self, mapper, adapter): for m2 in mapper._with_polymorphic_mappers: self._polymorphic_adapters[m2] = adapter for m in m2.iterate_to_root(): self._polymorphic_adapters[m.mapped_table] = self._polymorphic_adapters[m.local_table] = adapter def __set_select_from(self, from_obj): if isinstance(from_obj, expression._SelectBaseMixin): from_obj = from_obj.alias() self._from_obj = (from_obj,) equivs = self.__all_equivs() if isinstance(from_obj, expression.Alias): self._from_obj_alias = sql_util.ColumnAdapter(from_obj, equivs) def _get_polymorphic_adapter(self, entity, selectable): self.__mapper_loads_polymorphically_with(entity.mapper, sql_util.ColumnAdapter(selectable, entity.mapper._equivalent_columns)) def _reset_polymorphic_adapter(self, mapper): for m2 in mapper._with_polymorphic_mappers: self._polymorphic_adapters.pop(m2, None) for m in m2.iterate_to_root(): self._polymorphic_adapters.pop(m.mapped_table, None) self._polymorphic_adapters.pop(m.local_table, None) def __reset_joinpoint(self): self._joinpoint = None self._filter_aliases = None def __adapt_polymorphic_element(self, element): if isinstance(element, expression.FromClause): search = element elif hasattr(element, 'table'): search = element.table else: search = None if search: alias = self._polymorphic_adapters.get(search, None) if alias: return alias.adapt_clause(element) def __replace_element(self, adapters): def replace(elem): if '_halt_adapt' in elem._annotations: return elem for adapter in adapters: e = adapter(elem) if e: return e return replace def __replace_orm_element(self, adapters): def replace(elem): if '_halt_adapt' in elem._annotations: return elem if "_orm_adapt" in elem._annotations or "parententity" in elem._annotations: for adapter in adapters: e = adapter(elem) if e: return e return replace @_generative() def _adapt_all_clauses(self): self._disable_orm_filtering = True def _adapt_clause(self, clause, as_filter, orm_only): adapters = [] if as_filter and self._filter_aliases: adapters.append(self._filter_aliases.replace) if self._from_obj_alias: adapters.append(self._from_obj_alias.replace) if self._polymorphic_adapters: adapters.append(self.__adapt_polymorphic_element) if not adapters: return clause if getattr(self, '_disable_orm_filtering', not orm_only): return visitors.replacement_traverse(clause, {'column_collections':False}, self.__replace_element(adapters)) else: return visitors.replacement_traverse(clause, {'column_collections':False}, self.__replace_orm_element(adapters)) def _entity_zero(self): return self._entities[0] def _mapper_zero(self): return self._entity_zero().entity_zero def _extension_zero(self): ent = self._entity_zero() return getattr(ent, 'extension', ent.mapper.extension) @property def _mapper_entities(self): # TODO: this is wrong, its hardcoded to "priamry entity" when # for the case of __all_equivs() it should not be # the name of this accessor is wrong too for ent in self._entities: if hasattr(ent, 'primary_entity'): yield ent def _joinpoint_zero(self): return self._joinpoint or self._entity_zero().entity_zero def _mapper_zero_or_none(self): if not getattr(self._entities[0], 'primary_entity', False): return None return self._entities[0].mapper def _only_mapper_zero(self, rationale=None): if len(self._entities) > 1: raise sa_exc.InvalidRequestError(rationale or "This operation requires a Query against a single mapper.") return self._mapper_zero() def _only_entity_zero(self, rationale=None): if len(self._entities) > 1: raise sa_exc.InvalidRequestError(rationale or "This operation requires a Query against a single mapper.") return self._entity_zero() def _generate_mapper_zero(self): if not getattr(self._entities[0], 'primary_entity', False): raise sa_exc.InvalidRequestError("No primary mapper set up for this Query.") entity = self._entities[0]._clone() self._entities = [entity] + self._entities[1:] return entity def __all_equivs(self): equivs = {} for ent in self._mapper_entities: equivs.update(ent.mapper._equivalent_columns) return equivs def __no_criterion_condition(self, meth): if self._criterion or self._statement or self._from_obj or \ self._limit is not None or self._offset is not None or \ self._group_by: raise sa_exc.InvalidRequestError("Query.%s() being called on a Query with existing criterion. " % meth) self._from_obj = () self._statement = self._criterion = None self._order_by = self._group_by = self._distinct = False self.__joined_tables = {} def __no_clauseelement_condition(self, meth): if self._order_by: raise sa_exc.InvalidRequestError("Query.%s() being called on a Query with existing criterion. " % meth) self.__no_criterion_condition(meth) def __no_statement_condition(self, meth): if self._statement: raise sa_exc.InvalidRequestError( ("Query.%s() being called on a Query with an existing full " "statement - can't apply criterion.") % meth) def __no_limit_offset(self, meth): if self._limit is not None or self._offset is not None: # TODO: do we want from_self() to be implicit here ? i vote explicit for the time being raise sa_exc.InvalidRequestError("Query.%s() being called on a Query which already has LIMIT or OFFSET applied. " "To modify the row-limited results of a Query, call from_self() first. Otherwise, call %s() before limit() or offset() are applied." % (meth, meth) ) def __get_options(self, populate_existing=None, version_check=None, only_load_props=None, refresh_state=None): if populate_existing: self._populate_existing = populate_existing if version_check: self._version_check = version_check if refresh_state: self._refresh_state = refresh_state if only_load_props: self._only_load_props = set(only_load_props) return self def _clone(self): cls = self.__class__ q = cls.__new__(cls) q.__dict__ = self.__dict__.copy() return q @property def statement(self): """The full SELECT statement represented by this Query.""" return self._compile_context(labels=self._with_labels).statement._annotate({'_halt_adapt': True}) def subquery(self): """return the full SELECT statement represented by this Query, embedded within an Alias. Eager JOIN generation within the query is disabled. """ return self.enable_eagerloads(False).statement.alias() def __clause_element__(self): return self.enable_eagerloads(False).statement @_generative() def enable_eagerloads(self, value): """Control whether or not eager joins are rendered. When set to False, the returned Query will not render eager joins regardless of eagerload() options or mapper-level lazy=False configurations. This is used primarily when nesting the Query's statement into a subquery or other selectable. """ self._enable_eagerloads = value @_generative() def with_labels(self): """Apply column labels to the return value of Query.statement. Indicates that this Query's `statement` accessor should return a SELECT statement that applies labels to all columns in the form _; this is commonly used to disambiguate columns from multiple tables which have the same name. When the `Query` actually issues SQL to load rows, it always uses column labeling. """ self._with_labels = True @property def whereclause(self): """The WHERE criterion for this Query.""" return self._criterion @_generative() def _with_current_path(self, path): """indicate that this query applies to objects loaded within a certain path. Used by deferred loaders (see strategies.py) which transfer query options from an originating query to a newly generated query intended for the deferred load. """ self._current_path = path @_generative(__no_clauseelement_condition) def with_polymorphic(self, cls_or_mappers, selectable=None, discriminator=None): """Load columns for descendant mappers of this Query's mapper. Using this method will ensure that each descendant mapper's tables are included in the FROM clause, and will allow filter() criterion to be used against those tables. The resulting instances will also have those columns already loaded so that no "post fetch" of those columns will be required. :param cls_or_mappers: a single class or mapper, or list of class/mappers, which inherit from this Query's mapper. Alternatively, it may also be the string ``'*'``, in which case all descending mappers will be added to the FROM clause. :param selectable: a table or select() statement that will be used in place of the generated FROM clause. This argument is required if any of the desired mappers use concrete table inheritance, since SQLAlchemy currently cannot generate UNIONs among tables automatically. If used, the ``selectable`` argument must represent the full set of tables and columns mapped by every desired mapper. Otherwise, the unaccounted mapped columns will result in their table being appended directly to the FROM clause which will usually lead to incorrect results. :param discriminator: a column to be used as the "discriminator" column for the given selectable. If not given, the polymorphic_on attribute of the mapper will be used, if any. This is useful for mappers that don't have polymorphic loading behavior by default, such as concrete table mappers. """ entity = self._generate_mapper_zero() entity.set_with_polymorphic(self, cls_or_mappers, selectable=selectable, discriminator=discriminator) @_generative() def yield_per(self, count): """Yield only ``count`` rows at a time. WARNING: use this method with caution; if the same instance is present in more than one batch of rows, end-user changes to attributes will be overwritten. In particular, it's usually impossible to use this setting with eagerly loaded collections (i.e. any lazy=False) since those collections will be cleared for a new load when encountered in a subsequent result batch. """ self._yield_per = count def get(self, ident): """Return an instance of the object based on the given identifier, or None if not found. The `ident` argument is a scalar or tuple of primary key column values in the order of the table def's primary key columns. """ # convert composite types to individual args if hasattr(ident, '__composite_values__'): ident = ident.__composite_values__() key = self._only_mapper_zero("get() can only be used against a single mapped class.").identity_key_from_primary_key(ident) return self._get(key, ident) @classmethod @util.deprecated('Deprecated. Use sqlalchemy.orm.with_parent ' 'in conjunction with filter().') def query_from_parent(cls, instance, property, **kwargs): """Return a new Query with criterion corresponding to a parent instance. Return a newly constructed Query object, with criterion corresponding to a relationship to the given parent instance. instance a persistent or detached instance which is related to class represented by this query. property string name of the property which relates this query's class to the instance. \**kwargs all extra keyword arguments are propagated to the constructor of Query. """ mapper = object_mapper(instance) prop = mapper.get_property(property, resolve_synonyms=True) target = prop.mapper criterion = prop.compare(operators.eq, instance, value_is_parent=True) return Query(target, **kwargs).filter(criterion) @_generative() def correlate(self, *args): self._correlate = self._correlate.union(_orm_selectable(s) for s in args) @_generative() def autoflush(self, setting): """Return a Query with a specific 'autoflush' setting. Note that a Session with autoflush=False will not autoflush, even if this flag is set to True at the Query level. Therefore this flag is usually used only to disable autoflush for a specific Query. """ self._autoflush = setting @_generative() def populate_existing(self): """Return a Query that will refresh all instances loaded. This includes all entities accessed from the database, including secondary entities, eagerly-loaded collection items. All changes present on entities which are already present in the session will be reset and the entities will all be marked "clean". An alternative to populate_existing() is to expire the Session fully using session.expire_all(). """ self._populate_existing = True def with_parent(self, instance, property=None): """Add a join criterion corresponding to a relationship to the given parent instance. instance a persistent or detached instance which is related to class represented by this query. property string name of the property which relates this query's class to the instance. if None, the method will attempt to find a suitable property. Currently, this method only works with immediate parent relationships, but in the future may be enhanced to work across a chain of parent mappers. """ from sqlalchemy.orm import properties mapper = object_mapper(instance) if property is None: for prop in mapper.iterate_properties: if isinstance(prop, properties.PropertyLoader) and prop.mapper is self._mapper_zero(): break else: raise sa_exc.InvalidRequestError("Could not locate a property which relates instances of class '%s' to instances of class '%s'" % (self._mapper_zero().class_.__name__, instance.__class__.__name__)) else: prop = mapper.get_property(property, resolve_synonyms=True) return self.filter(prop.compare(operators.eq, instance, value_is_parent=True)) @_generative() def add_entity(self, entity, alias=None): """add a mapped entity to the list of result columns to be returned.""" if alias: entity = aliased(entity, alias) self._entities = list(self._entities) m = _MapperEntity(self, entity) self.__setup_aliasizers([m]) def from_self(self, *entities): """return a Query that selects from this Query's SELECT statement. \*entities - optional list of entities which will replace those being selected. """ fromclause = self.with_labels().enable_eagerloads(False).statement.correlate(None) q = self._from_selectable(fromclause) if entities: q._set_entities(entities) return q _from_self = from_self @_generative() def _from_selectable(self, fromclause): self._statement = self._criterion = None self._order_by = self._group_by = self._distinct = False self._limit = self._offset = None self.__set_select_from(fromclause) def values(self, *columns): """Return an iterator yielding result tuples corresponding to the given list of columns""" if not columns: return iter(()) q = self._clone() q._set_entities(columns, entity_wrapper=_ColumnEntity) if not q._yield_per: q._yield_per = 10 return iter(q) _values = values def value(self, column): """Return a scalar result corresponding to the given column expression.""" try: return self.values(column).next()[0] except StopIteration: return None @_generative() def add_column(self, column): """Add a SQL ColumnElement to the list of result columns to be returned.""" self._entities = list(self._entities) l = len(self._entities) _ColumnEntity(self, column) # _ColumnEntity may add many entities if the # given arg is a FROM clause self.__setup_aliasizers(self._entities[l:]) def options(self, *args): """Return a new Query object, applying the given list of MapperOptions. """ return self.__options(False, *args) def _conditional_options(self, *args): return self.__options(True, *args) @_generative() def __options(self, conditional, *args): # most MapperOptions write to the '_attributes' dictionary, # so copy that as well self._attributes = self._attributes.copy() opts = [o for o in util.flatten_iterator(args)] self._with_options = self._with_options + opts if conditional: for opt in opts: opt.process_query_conditionally(self) else: for opt in opts: opt.process_query(self) @_generative() def with_lockmode(self, mode): """Return a new Query object with the specified locking mode.""" self._lockmode = mode @_generative() def params(self, *args, **kwargs): """add values for bind parameters which may have been specified in filter(). parameters may be specified using \**kwargs, or optionally a single dictionary as the first positional argument. The reason for both is that \**kwargs is convenient, however some parameter dictionaries contain unicode keys in which case \**kwargs cannot be used. """ if len(args) == 1: kwargs.update(args[0]) elif len(args) > 0: raise sa_exc.ArgumentError("params() takes zero or one positional argument, which is a dictionary.") self._params = self._params.copy() self._params.update(kwargs) @_generative(__no_statement_condition, __no_limit_offset) def filter(self, criterion): """apply the given filtering criterion to the query and return the newly resulting ``Query`` the criterion is any sql.ClauseElement applicable to the WHERE clause of a select. """ if isinstance(criterion, basestring): criterion = sql.text(criterion) if criterion is not None and not isinstance(criterion, sql.ClauseElement): raise sa_exc.ArgumentError("filter() argument must be of type sqlalchemy.sql.ClauseElement or string") criterion = self._adapt_clause(criterion, True, True) if self._criterion is not None: self._criterion = self._criterion & criterion else: self._criterion = criterion def filter_by(self, **kwargs): """apply the given filtering criterion to the query and return the newly resulting ``Query``.""" clauses = [_entity_descriptor(self._joinpoint_zero(), key)[0] == value for key, value in kwargs.iteritems()] return self.filter(sql.and_(*clauses)) @_generative(__no_statement_condition, __no_limit_offset) @util.accepts_a_list_as_starargs(list_deprecation='pending') def order_by(self, *criterion): """apply one or more ORDER BY criterion to the query and return the newly resulting ``Query``""" if len(criterion) == 1 and criterion[0] is None: self._order_by = None else: criterion = [self._adapt_clause(expression._literal_as_text(o), True, True) for o in criterion] if self._order_by is False or self._order_by is None: self._order_by = criterion else: self._order_by = self._order_by + criterion @_generative(__no_statement_condition, __no_limit_offset) @util.accepts_a_list_as_starargs(list_deprecation='pending') def group_by(self, *criterion): """apply one or more GROUP BY criterion to the query and return the newly resulting ``Query``""" criterion = list(chain(*[_orm_columns(c) for c in criterion])) criterion = [self._adapt_clause(expression._literal_as_text(o), True, True) for o in criterion] if self._group_by is False: self._group_by = criterion else: self._group_by = self._group_by + criterion @_generative(__no_statement_condition, __no_limit_offset) def having(self, criterion): """apply a HAVING criterion to the query and return the newly resulting ``Query``.""" if isinstance(criterion, basestring): criterion = sql.text(criterion) if criterion is not None and not isinstance(criterion, sql.ClauseElement): raise sa_exc.ArgumentError("having() argument must be of type sqlalchemy.sql.ClauseElement or string") criterion = self._adapt_clause(criterion, True, True) if self._having is not None: self._having = self._having & criterion else: self._having = criterion def union(self, *q): """Produce a UNION of this Query against one or more queries. e.g.:: q1 = sess.query(SomeClass).filter(SomeClass.foo=='bar') q2 = sess.query(SomeClass).filter(SomeClass.bar=='foo') q3 = q1.union(q2) The method accepts multiple Query objects so as to control the level of nesting. A series of ``union()`` calls such as:: x.union(y).union(z).all() will nest on each ``union()``, and produces:: SELECT * FROM (SELECT * FROM (SELECT * FROM X UNION SELECT * FROM y) UNION SELECT * FROM Z) Whereas:: x.union(y, z).all() produces:: SELECT * FROM (SELECT * FROM X UNION SELECT * FROM y UNION SELECT * FROM Z) """ return self._from_selectable( expression.union(*([self]+ list(q)))) def union_all(self, *q): """Produce a UNION ALL of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. """ return self._from_selectable( expression.union_all(*([self]+ list(q))) ) def intersect(self, *q): """Produce an INTERSECT of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. """ return self._from_selectable( expression.intersect(*([self]+ list(q))) ) def intersect_all(self, *q): """Produce an INTERSECT ALL of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. """ return self._from_selectable( expression.intersect_all(*([self]+ list(q))) ) def except_(self, *q): """Produce an EXCEPT of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. """ return self._from_selectable( expression.except_(*([self]+ list(q))) ) def except_all(self, *q): """Produce an EXCEPT ALL of this Query against one or more queries. Works the same way as :meth:`~sqlalchemy.orm.query.Query.union`. See that method for usage examples. """ return self._from_selectable( expression.except_all(*([self]+ list(q))) ) @util.accepts_a_list_as_starargs(list_deprecation='pending') def join(self, *props, **kwargs): """Create a join against this ``Query`` object's criterion and apply generatively, returning the newly resulting ``Query``. Each element in \*props may be: * a string property name, i.e. "rooms". This will join along the relation of the same name from this Query's "primary" mapper, if one is present. * a class-mapped attribute, i.e. Houses.rooms. This will create a join from "Houses" table to that of the "rooms" relation. * a 2-tuple containing a target class or selectable, and an "ON" clause. The ON clause can be the property name/ attribute like above, or a SQL expression. e.g.:: # join along string attribute names session.query(Company).join('employees') session.query(Company).join('employees', 'tasks') # join the Person entity to an alias of itself, # along the "friends" relation PAlias = aliased(Person) session.query(Person).join((Palias, Person.friends)) # join from Houses to the "rooms" attribute on the # "Colonials" subclass of Houses, then join to the # "closets" relation on Room session.query(Houses).join(Colonials.rooms, Room.closets) # join from Company entities to the "employees" collection, # using "people JOIN engineers" as the target. Then join # to the "computers" collection on the Engineer entity. session.query(Company).join((people.join(engineers), 'employees'), Engineer.computers) # join from Articles to Keywords, using the "keywords" attribute. # assume this is a many-to-many relation. session.query(Article).join(Article.keywords) # same thing, but spelled out entirely explicitly # including the association table. session.query(Article).join( (article_keywords, Articles.id==article_keywords.c.article_id), (Keyword, Keyword.id==article_keywords.c.keyword_id) ) \**kwargs include: aliased - when joining, create anonymous aliases of each table. This is used for self-referential joins or multiple joins to the same table. Consider usage of the aliased(SomeClass) construct as a more explicit approach to this. from_joinpoint - when joins are specified using string property names, locate the property from the mapper found in the most recent previous join() call, instead of from the root entity. """ aliased, from_joinpoint = kwargs.pop('aliased', False), kwargs.pop('from_joinpoint', False) if kwargs: raise TypeError("unknown arguments: %s" % ','.join(kwargs.iterkeys())) return self.__join(props, outerjoin=False, create_aliases=aliased, from_joinpoint=from_joinpoint) @util.accepts_a_list_as_starargs(list_deprecation='pending') def outerjoin(self, *props, **kwargs): """Create a left outer join against this ``Query`` object's criterion and apply generatively, retunring the newly resulting ``Query``. Usage is the same as the ``join()`` method. """ aliased, from_joinpoint = kwargs.pop('aliased', False), kwargs.pop('from_joinpoint', False) if kwargs: raise TypeError("unknown arguments: %s" % ','.join(kwargs.iterkeys())) return self.__join(props, outerjoin=True, create_aliases=aliased, from_joinpoint=from_joinpoint) @_generative(__no_statement_condition, __no_limit_offset) def __join(self, keys, outerjoin, create_aliases, from_joinpoint): # copy collections that may mutate so they do not affect # the copied-from query. self.__currenttables = set(self.__currenttables) self._polymorphic_adapters = self._polymorphic_adapters.copy() # start from the beginning unless from_joinpoint is set. if not from_joinpoint: self.__reset_joinpoint() clause = replace_clause_index = None # after the method completes, # the query's joinpoint will be set to this. right_entity = None for arg1 in util.to_list(keys): aliased_entity = False alias_criterion = False left_entity = right_entity prop = of_type = right_entity = right_mapper = None # distinguish between tuples, scalar args if isinstance(arg1, tuple): arg1, arg2 = arg1 else: arg2 = None # determine onclause/right_entity. there # is a little bit of legacy behavior still at work here # which means they might be in either order. may possibly # lock this down to (right_entity, onclause) in 0.6. if isinstance(arg2, (interfaces.PropComparator, basestring)): onclause = arg2 right_entity = arg1 elif isinstance(arg1, (interfaces.PropComparator, basestring)): onclause = arg1 right_entity = arg2 else: onclause = arg2 right_entity = arg1 # extract info from the onclause argument, determine # left_entity and right_entity. if isinstance(onclause, interfaces.PropComparator): of_type = getattr(onclause, '_of_type', None) prop = onclause.property descriptor = onclause if not left_entity: left_entity = onclause.parententity if of_type: right_mapper = of_type else: right_mapper = prop.mapper if not right_entity: right_entity = right_mapper elif isinstance(onclause, basestring): if not left_entity: left_entity = self._joinpoint_zero() descriptor, prop = _entity_descriptor(left_entity, onclause) right_mapper = prop.mapper if not right_entity: right_entity = right_mapper elif not left_entity: left_entity = self._joinpoint_zero() if not clause and self._from_obj: mp, left_selectable, is_aliased_class = _entity_info(left_entity) replace_clause_index, clause = sql_util.find_join_source(self._from_obj, left_selectable) if not clause: clause = left_selectable if not clause: for ent in self._entities: if ent.corresponds_to(left_entity): clause = ent.selectable break # TODO: # this provides one kind of "backwards join" # tested in test/orm/query.py. # removal of this has been considered, but maybe not # see [ticket:1445] if not clause: if isinstance(onclause, interfaces.PropComparator): clause = onclause.__clause_element__() if not clause: raise sa_exc.InvalidRequestError("Could not find a FROM clause to join from") # if we have a MapperProperty and the onclause is not already # an instrumented descriptor. this catches of_type() # PropComparators and string-based on clauses. if prop and not isinstance(onclause, attributes.QueryableAttribute): onclause = prop # start looking at the right side of the join mp, right_selectable, is_aliased_class = _entity_info(right_entity) if mp is not None and right_mapper is not None and not mp.common_parent(right_mapper): raise sa_exc.InvalidRequestError( "Join target %s does not correspond to the right side of join condition %s" % (right_entity, onclause) ) if not right_mapper and mp: right_mapper = mp # determine if we need to wrap the right hand side in an alias. # this occurs based on the create_aliases flag, or if the target # is a selectable, Join, or polymorphically-loading mapper if right_mapper and not is_aliased_class: if right_entity is right_selectable: if not right_selectable.is_derived_from(right_mapper.mapped_table): raise sa_exc.InvalidRequestError( "Selectable '%s' is not derived from '%s'" % (right_selectable.description, right_mapper.mapped_table.description)) if not isinstance(right_selectable, expression.Alias): right_selectable = right_selectable.alias() right_entity = aliased(right_mapper, right_selectable) alias_criterion = True elif create_aliases: right_entity = aliased(right_mapper) alias_criterion = True elif right_mapper.with_polymorphic or isinstance(right_mapper.mapped_table, expression.Join): right_entity = aliased(right_mapper) alias_criterion = True aliased_entity = True elif prop: # for joins across plain relation()s, try not to specify the # same joins twice. the __currenttables collection tracks # what plain mapped tables we've joined to already. if prop.table in self.__currenttables: if prop.secondary is not None and prop.secondary not in self.__currenttables: # TODO: this check is not strong enough for different paths to the same endpoint which # does not use secondary tables raise sa_exc.InvalidRequestError("Can't join to property '%s'; a path to this " "table along a different secondary table already " "exists. Use the `alias=True` argument to `join()`." % descriptor) continue if prop.secondary: self.__currenttables.add(prop.secondary) self.__currenttables.add(prop.table) if of_type: right_entity = of_type else: right_entity = prop.mapper # create adapters to the right side, if we've created aliases if alias_criterion: right_adapter = ORMAdapter(right_entity, equivalents=right_mapper._equivalent_columns, chain_to=self._filter_aliases) # if the onclause is a ClauseElement, adapt it with our right # adapter, then with our query-wide adaptation if any. if isinstance(onclause, expression.ClauseElement): if alias_criterion: onclause = right_adapter.traverse(onclause) onclause = self._adapt_clause(onclause, False, True) # determine if we want _ORMJoin to alias the onclause # to the given left side. This is used if we're joining against a # select_from() selectable, from_self() call, or the onclause # has been resolved into a MapperProperty. Otherwise we assume # the onclause itself contains more specific information on how to # construct the onclause. join_to_left = not is_aliased_class or \ onclause is prop or \ self._from_obj_alias and clause is self._from_obj[0] # create the join clause = orm_join(clause, right_entity, onclause, isouter=outerjoin, join_to_left=join_to_left) # set up state for the query as a whole if alias_criterion: # adapt filter() calls based on our right side adaptation self._filter_aliases = right_adapter # if a polymorphic entity was aliased, establish that # so that MapperEntity/ColumnEntity can pick up on it # and adapt when it renders columns and fetches them from results if aliased_entity: self.__mapper_loads_polymorphically_with( right_mapper, ORMAdapter(right_entity, equivalents=right_mapper._equivalent_columns) ) if replace_clause_index is not None: l = list(self._from_obj) l[replace_clause_index] = clause self._from_obj = tuple(l) else: self._from_obj = self._from_obj + (clause,) # future joins with from_joinpoint=True join from our established right_entity. self._joinpoint = right_entity @_generative(__no_statement_condition) def reset_joinpoint(self): """return a new Query reset the 'joinpoint' of this Query reset back to the starting mapper. Subsequent generative calls will be constructed from the new joinpoint. Note that each call to join() or outerjoin() also starts from the root. """ self.__reset_joinpoint() @_generative(__no_clauseelement_condition) def select_from(self, from_obj): """Set the `from_obj` parameter of the query and return the newly resulting ``Query``. This replaces the table which this Query selects from with the given table. `from_obj` is a single table or selectable. """ if isinstance(from_obj, (tuple, list)): # from_obj is actually a list again as of 0.5.3. so this restriction here # is somewhat artificial, but is still in place since select_from() implies aliasing all further # criterion against what's placed here, and its less complex to only # keep track of a single aliased FROM element being selected against. This could in theory be opened # up again to more complexity. util.warn_deprecated("select_from() now accepts a single Selectable as its argument, which replaces any existing FROM criterion.") from_obj = from_obj[-1] if not isinstance(from_obj, expression.FromClause): raise sa_exc.ArgumentError("select_from() accepts FromClause objects only.") self.__set_select_from(from_obj) def __getitem__(self, item): if isinstance(item, slice): start, stop, step = util.decode_slice(item) if isinstance(stop, int) and isinstance(start, int) and stop - start <= 0: return [] # perhaps we should execute a count() here so that we # can still use LIMIT/OFFSET ? elif (isinstance(start, int) and start < 0) \ or (isinstance(stop, int) and stop < 0): return list(self)[item] res = self.slice(start, stop) if step is not None: return list(res)[None:None:item.step] else: return list(res) else: return list(self[item:item+1])[0] @_generative(__no_statement_condition) def slice(self, start, stop): """apply LIMIT/OFFSET to the ``Query`` based on a range and return the newly resulting ``Query``.""" if start is not None and stop is not None: self._offset = (self._offset or 0) + start self._limit = stop - start elif start is None and stop is not None: self._limit = stop elif start is not None and stop is None: self._offset = (self._offset or 0) + start @_generative(__no_statement_condition) def limit(self, limit): """Apply a ``LIMIT`` to the query and return the newly resulting ``Query``. """ self._limit = limit @_generative(__no_statement_condition) def offset(self, offset): """Apply an ``OFFSET`` to the query and return the newly resulting ``Query``. """ self._offset = offset @_generative(__no_statement_condition) def distinct(self): """Apply a ``DISTINCT`` to the query and return the newly resulting ``Query``. """ self._distinct = True def all(self): """Return the results represented by this ``Query`` as a list. This results in an execution of the underlying query. """ return list(self) @_generative(__no_clauseelement_condition) def from_statement(self, statement): """Execute the given SELECT statement and return results. This method bypasses all internal statement compilation, and the statement is executed without modification. The statement argument is either a string, a ``select()`` construct, or a ``text()`` construct, and should return the set of columns appropriate to the entity class represented by this ``Query``. Also see the ``instances()`` method. """ if isinstance(statement, basestring): statement = sql.text(statement) if not isinstance(statement, (expression._TextClause, expression._SelectBaseMixin)): raise sa_exc.ArgumentError("from_statement accepts text(), select(), and union() objects only.") self._statement = statement def first(self): """Return the first result of this ``Query`` or None if the result doesn't contain any row. This results in an execution of the underlying query. """ if self._statement: ret = list(self)[0:1] else: ret = list(self[0:1]) if len(ret) > 0: return ret[0] else: return None def one(self): """Return exactly one result or raise an exception. Raises ``sqlalchemy.orm.exc.NoResultFound`` if the query selects no rows. Raises ``sqlalchemy.orm.exc.MultipleResultsFound`` if multiple rows are selected. This results in an execution of the underlying query. """ if self._statement: raise sa_exc.InvalidRequestError( "one() not available when from_statement() is used; " "use `first()` instead.") ret = list(self[0:2]) if len(ret) == 1: return ret[0] elif len(ret) == 0: raise orm_exc.NoResultFound("No row was found for one()") else: raise orm_exc.MultipleResultsFound( "Multiple rows were found for one()") def scalar(self): """Return the first element of the first result or None. >>> session.query(Item).scalar() >>> session.query(Item.id).scalar() 1 >>> session.query(Item.id).filter(Item.id < 0).scalar() None >>> session.query(Item.id, Item.name).scalar() 1 >>> session.query(func.count(Parent.id)).scalar() 20 This results in an execution of the underlying query. """ try: ret = list(self)[0] if not isinstance(ret, tuple): return ret return ret[0] except IndexError: return None def __iter__(self): context = self._compile_context() context.statement.use_labels = True if self._autoflush and not self._populate_existing: self.session._autoflush() return self._execute_and_instances(context) def _execute_and_instances(self, querycontext): result = self.session.execute(querycontext.statement, params=self._params, mapper=self._mapper_zero_or_none()) return self.instances(result, querycontext) def instances(self, cursor, __context=None): """Given a ResultProxy cursor as returned by connection.execute(), return an ORM result as an iterator. e.g.:: result = engine.execute("select * from users") for u in session.query(User).instances(result): print u """ session = self.session context = __context if context is None: context = QueryContext(self) context.runid = _new_runid() filtered = bool(list(self._mapper_entities)) single_entity = filtered and len(self._entities) == 1 if filtered: if single_entity: filter = lambda x: util.unique_list(x, util.IdentitySet) else: filter = util.unique_list else: filter = None custom_rows = single_entity and 'append_result' in self._entities[0].extension (process, labels) = zip(*[query_entity.row_processor(self, context, custom_rows) for query_entity in self._entities]) if not single_entity: labels = dict((label, property(itemgetter(i))) for i, label in enumerate(labels) if label) rowtuple = type.__new__(type, "RowTuple", (tuple,), labels) rowtuple.keys = labels.keys while True: context.progress = {} context.partials = {} if self._yield_per: fetch = cursor.fetchmany(self._yield_per) if not fetch: break else: fetch = cursor.fetchall() if custom_rows: rows = [] for row in fetch: process[0](context, row, rows) elif single_entity: rows = [process[0](context, row) for row in fetch] else: rows = [rowtuple(proc(context, row) for proc in process) for row in fetch] if filter: rows = filter(rows) if context.refresh_state and self._only_load_props and context.refresh_state in context.progress: context.refresh_state.commit(context.refresh_state.dict, self._only_load_props) context.progress.pop(context.refresh_state) session._finalize_loaded(context.progress) for ii, (dict_, attrs) in context.partials.items(): ii.commit(dict_, attrs) for row in rows: yield row if not self._yield_per: break iterate_instances = util.deprecated()(instances) def _get(self, key=None, ident=None, refresh_state=None, lockmode=None, only_load_props=None): lockmode = lockmode or self._lockmode if not self._populate_existing and not refresh_state and not self._mapper_zero().always_refresh and lockmode is None: try: instance = self.session.identity_map[key] state = attributes.instance_state(instance) if state.expired: try: state() except orm_exc.ObjectDeletedError: self.session._remove_newly_deleted(state) return None return instance except KeyError: pass if ident is None: if key is not None: ident = key[1] else: ident = util.to_list(ident) if refresh_state is None: q = self._clone() q.__no_criterion_condition("get") else: q = self._clone() if ident is not None: mapper = q._mapper_zero() params = {} (_get_clause, _get_params) = mapper._get_clause _get_clause = q._adapt_clause(_get_clause, True, False) q._criterion = _get_clause for i, primary_key in enumerate(mapper.primary_key): try: params[_get_params[primary_key].key] = ident[i] except IndexError: raise sa_exc.InvalidRequestError("Could not find enough values to formulate primary key for " "query.get(); primary key columns are %s" % ', '.join("'%s'" % c for c in mapper.primary_key)) q._params = params if lockmode is not None: q._lockmode = lockmode q.__get_options( populate_existing=bool(refresh_state), version_check=(lockmode is not None), only_load_props=only_load_props, refresh_state=refresh_state) q._order_by = None try: # call using all() to avoid LIMIT compilation complexity return q.all()[0] except IndexError: return None @property def _select_args(self): return { 'limit':self._limit, 'offset':self._offset, 'distinct':self._distinct, 'group_by':self._group_by or None, 'having':self._having or None } @property def _should_nest_selectable(self): kwargs = self._select_args return (kwargs.get('limit') is not None or kwargs.get('offset') is not None or kwargs.get('distinct', False)) def count(self): """Apply this query's criterion to a SELECT COUNT statement. If column expressions or LIMIT/OFFSET/DISTINCT are present, the query "SELECT count(1) FROM (SELECT ...)" is issued, so that the result matches the total number of rows this query would return. For mapped entities, the primary key columns of each is written to the columns clause of the nested SELECT statement. For a Query which is only against mapped entities, a simpler "SELECT count(1) FROM table1, table2, ... WHERE criterion" is issued. """ should_nest = [self._should_nest_selectable] def ent_cols(ent): if isinstance(ent, _MapperEntity): return ent.mapper.primary_key else: should_nest[0] = True return [ent.column] return self._col_aggregate(sql.literal_column('1'), sql.func.count, nested_cols=chain(*[ent_cols(ent) for ent in self._entities]), should_nest = should_nest[0] ) def _col_aggregate(self, col, func, nested_cols=None, should_nest=False): context = QueryContext(self) for entity in self._entities: entity.setup_context(self, context) if context.from_clause: from_obj = list(context.from_clause) else: from_obj = context.froms self._adjust_for_single_inheritance(context) whereclause = context.whereclause if should_nest: if not nested_cols: nested_cols = [col] else: nested_cols = list(nested_cols) s = sql.select(nested_cols, whereclause, from_obj=from_obj, use_labels=True, **self._select_args) s = s.alias() s = sql.select([func(s.corresponding_column(col) or col)]).select_from(s) else: s = sql.select([func(col)], whereclause, from_obj=from_obj, **self._select_args) if self._autoflush and not self._populate_existing: self.session._autoflush() return self.session.scalar(s, params=self._params, mapper=self._mapper_zero()) def delete(self, synchronize_session='fetch'): """Perform a bulk delete query. Deletes rows matched by this query from the database. :param synchronize_session: chooses the strategy for the removal of matched objects from 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 typically occurs after a commit(). Before the expiration, objects may still remain in the session which were in fact deleted which can lead to confusing results if they are accessed via get() or already loaded collections. 'fetch' performs a select query before the delete to find objects that are matched by the delete query and need to be removed from the session. Matched objects are removed from the session. 'fetch' is the default strategy. 'evaluate' experimental feature. Tries to evaluate the querys criteria in Python straight on the objects in the session. If evaluation of the criteria isn't implemented, the 'fetch' strategy will be used as a fallback. The expression evaluator currently doesn't account for differing string collations between the database and Python. Returns the number of rows deleted, excluding any cascades. The method does *not* offer in-Python cascading of relations - it is assumed that ON DELETE CASCADE is configured for any foreign key references which require it. The Session needs to be expired (occurs automatically after commit(), or call expire_all()) in order for the state of dependent objects subject to delete or delete-orphan cascade to be correctly represented. Also, the ``before_delete()`` and ``after_delete()`` :class:`~sqlalchemy.orm.interfaces.MapperExtension` methods are not called from this method. For a delete hook here, use the ``after_bulk_delete()`` :class:`~sqlalchemy.orm.interfaces.MapperExtension` method. """ #TODO: lots of duplication and ifs - probably needs to be refactored to strategies #TODO: cascades need handling. if synchronize_session not in [False, 'evaluate', 'fetch']: raise sa_exc.ArgumentError("Valid strategies for session synchronization are False, 'evaluate' and 'fetch'") self = self.enable_eagerloads(False) context = self._compile_context() if len(context.statement.froms) != 1 or not isinstance(context.statement.froms[0], schema.Table): raise sa_exc.ArgumentError("Only deletion via a single table query is currently supported") primary_table = context.statement.froms[0] session = self.session if synchronize_session == 'evaluate': try: evaluator_compiler = evaluator.EvaluatorCompiler() eval_condition = evaluator_compiler.process(self.whereclause) except evaluator.UnevaluatableError: synchronize_session = 'fetch' delete_stmt = sql.delete(primary_table, context.whereclause) if synchronize_session == 'fetch': #TODO: use RETURNING when available select_stmt = context.statement.with_only_columns(primary_table.primary_key) matched_rows = session.execute(select_stmt, params=self._params).fetchall() if self._autoflush: session._autoflush() result = session.execute(delete_stmt, params=self._params) if synchronize_session == 'evaluate': target_cls = self._mapper_zero().class_ #TODO: detect when the where clause is a trivial primary key match objs_to_expunge = [obj for (cls, pk),obj in session.identity_map.iteritems() if issubclass(cls, target_cls) and eval_condition(obj)] for obj in objs_to_expunge: session._remove_newly_deleted(attributes.instance_state(obj)) elif synchronize_session == 'fetch': target_mapper = self._mapper_zero() for primary_key in matched_rows: identity_key = target_mapper.identity_key_from_primary_key(list(primary_key)) if identity_key in session.identity_map: session._remove_newly_deleted(attributes.instance_state(session.identity_map[identity_key])) for ext in session.extensions: ext.after_bulk_delete(session, self, context, result) return result.rowcount def update(self, values, synchronize_session='expire'): """Perform a bulk update query. Updates rows matched by this query in the database. :param values: a dictionary with attributes names as keys and literal values or sql expressions as values. :param synchronize_session: chooses the strategy to update the attributes on objects in the session. Valid values are: False don't synchronize the session. Use this when you don't need to use the session after the update or you can be sure that none of the matched objects are in the session. 'expire' performs a select query before the update to find objects that are matched by the update query. The updated attributes are expired on matched objects. 'evaluate' experimental feature. Tries to evaluate the querys criteria in Python straight on the objects in the session. If evaluation of the criteria isn't implemented, the 'expire' strategy will be used as a fallback. The expression evaluator currently doesn't account for differing string collations between the database and Python. Returns the number of rows matched by the update. The method does *not* offer in-Python cascading of relations - it is assumed that ON UPDATE CASCADE is configured for any foreign key references which require it. The Session needs to be expired (occurs automatically after commit(), or call expire_all()) in order for the state of dependent objects subject foreign key cascade to be correctly represented. Also, the ``before_update()`` and ``after_update()`` :class:`~sqlalchemy.orm.interfaces.MapperExtension` methods are not called from this method. For an update hook here, use the ``after_bulk_update()`` :class:`~sqlalchemy.orm.interfaces.SessionExtension` method. """ #TODO: value keys need to be mapped to corresponding sql cols and instr.attr.s to string keys #TODO: updates of manytoone relations need to be converted to fk assignments #TODO: cascades need handling. if synchronize_session not in [False, 'evaluate', 'expire']: raise sa_exc.ArgumentError("Valid strategies for session synchronization are False, 'evaluate' and 'expire'") self = self.enable_eagerloads(False) context = self._compile_context() if len(context.statement.froms) != 1 or not isinstance(context.statement.froms[0], schema.Table): raise sa_exc.ArgumentError("Only update via a single table query is currently supported") primary_table = context.statement.froms[0] session = self.session if synchronize_session == 'evaluate': try: evaluator_compiler = evaluator.EvaluatorCompiler() eval_condition = evaluator_compiler.process(self.whereclause) value_evaluators = {} for key,value in values.items(): key = expression._column_as_key(key) value_evaluators[key] = evaluator_compiler.process(expression._literal_as_binds(value)) except evaluator.UnevaluatableError: synchronize_session = 'expire' update_stmt = sql.update(primary_table, context.whereclause, values) if synchronize_session == 'expire': select_stmt = context.statement.with_only_columns(primary_table.primary_key) matched_rows = session.execute(select_stmt, params=self._params).fetchall() if self._autoflush: session._autoflush() result = session.execute(update_stmt, params=self._params) if synchronize_session == 'evaluate': target_cls = self._mapper_zero().class_ for (cls, pk),obj in session.identity_map.iteritems(): evaluated_keys = value_evaluators.keys() if issubclass(cls, target_cls) and eval_condition(obj): state, dict_ = attributes.instance_state(obj), attributes.instance_dict(obj) # only evaluate unmodified attributes to_evaluate = state.unmodified.intersection(evaluated_keys) for key in to_evaluate: dict_[key] = value_evaluators[key](obj) state.commit(dict_, list(to_evaluate)) # expire attributes with pending changes (there was no autoflush, so they are overwritten) state.expire_attributes(set(evaluated_keys).difference(to_evaluate)) elif synchronize_session == 'expire': target_mapper = self._mapper_zero() for primary_key in matched_rows: identity_key = target_mapper.identity_key_from_primary_key(list(primary_key)) if identity_key in session.identity_map: session.expire(session.identity_map[identity_key], values.keys()) for ext in session.extensions: ext.after_bulk_update(session, self, context, result) return result.rowcount def _compile_context(self, labels=True): context = QueryContext(self) if context.statement: return context if self._lockmode: try: for_update = {'read': 'read', 'update': True, 'update_nowait': 'nowait', None: False}[self._lockmode] except KeyError: raise sa_exc.ArgumentError("Unknown lockmode '%s'" % self._lockmode) else: for_update = False for entity in self._entities: entity.setup_context(self, context) eager_joins = context.eager_joins.values() if context.from_clause: froms = list(context.from_clause) # "load from explicit FROMs" mode, i.e. when select_from() or join() is used else: froms = context.froms # "load from discrete FROMs" mode, i.e. when each _MappedEntity has its own FROM self._adjust_for_single_inheritance(context) if not context.primary_columns: if self._only_load_props: raise sa_exc.InvalidRequestError("No column-based properties specified for refresh operation." " Use session.expire() to reload collections and related items.") else: raise sa_exc.InvalidRequestError("Query contains no columns with which to SELECT from.") if eager_joins and self._should_nest_selectable: # for eager joins present and LIMIT/OFFSET/DISTINCT, wrap the query inside a select, # then append eager joins onto that if context.order_by: order_by_col_expr = list(chain(*[sql_util.find_columns(o) for o in context.order_by])) else: context.order_by = None order_by_col_expr = [] inner = sql.select( context.primary_columns + order_by_col_expr, context.whereclause, from_obj=froms, use_labels=labels, correlate=False, order_by=context.order_by, **self._select_args ) if self._correlate: inner = inner.correlate(*self._correlate) inner = inner.alias() equivs = self.__all_equivs() context.adapter = sql_util.ColumnAdapter(inner, equivs) statement = sql.select([inner] + context.secondary_columns, for_update=for_update, use_labels=labels) from_clause = inner for eager_join in eager_joins: # EagerLoader places a 'stop_on' attribute on the join, # giving us a marker as to where the "splice point" of the join should be from_clause = sql_util.splice_joins(from_clause, eager_join, eager_join.stop_on) statement.append_from(from_clause) if context.order_by: statement.append_order_by(*context.adapter.copy_and_process(context.order_by)) statement.append_order_by(*context.eager_order_by) else: if not context.order_by: context.order_by = None if self._distinct and context.order_by: order_by_col_expr = list(chain(*[sql_util.find_columns(o) for o in context.order_by])) context.primary_columns += order_by_col_expr froms += context.eager_joins.values() statement = sql.select( context.primary_columns + context.secondary_columns, context.whereclause, from_obj=froms, use_labels=labels, for_update=for_update, correlate=False, order_by=context.order_by, **self._select_args ) if self._correlate: statement = statement.correlate(*self._correlate) if context.eager_order_by: statement.append_order_by(*context.eager_order_by) context.statement = statement return context def _adjust_for_single_inheritance(self, context): """Apply single-table-inheritance filtering. For all distinct single-table-inheritance mappers represented in the columns clause of this query, add criterion to the WHERE clause of the given QueryContext such that only the appropriate subtypes are selected from the total results. """ for entity, (mapper, adapter, s, i, w) in self._mapper_adapter_map.iteritems(): single_crit = mapper._single_table_criterion if single_crit: if adapter: single_crit = adapter.traverse(single_crit) single_crit = self._adapt_clause(single_crit, False, False) context.whereclause = sql.and_(context.whereclause, single_crit) def __str__(self): return str(self._compile_context().statement) class _QueryEntity(object): """represent an entity column returned within a Query result.""" def __new__(cls, *args, **kwargs): if cls is _QueryEntity: entity = args[1] if not isinstance(entity, basestring) and _is_mapped_class(entity): cls = _MapperEntity else: cls = _ColumnEntity return object.__new__(cls) def _clone(self): q = self.__class__.__new__(self.__class__) q.__dict__ = self.__dict__.copy() return q class _MapperEntity(_QueryEntity): """mapper/class/AliasedClass entity""" def __init__(self, query, entity): self.primary_entity = not query._entities query._entities.append(self) self.entities = [entity] self.entity_zero = entity def setup_entity(self, entity, mapper, adapter, from_obj, is_aliased_class, with_polymorphic): self.mapper = mapper self.extension = self.mapper.extension self.adapter = adapter self.selectable = from_obj self._with_polymorphic = with_polymorphic self._polymorphic_discriminator = None self.is_aliased_class = is_aliased_class if is_aliased_class: self.path_entity = self.entity = self.entity_zero = entity else: self.path_entity = mapper.base_mapper self.entity = self.entity_zero = mapper def set_with_polymorphic(self, query, cls_or_mappers, selectable, discriminator): if cls_or_mappers is None: query._reset_polymorphic_adapter(self.mapper) return mappers, from_obj = self.mapper._with_polymorphic_args(cls_or_mappers, selectable) self._with_polymorphic = mappers self._polymorphic_discriminator = discriminator # TODO: do the wrapped thing here too so that with_polymorphic() can be # applied to aliases if not self.is_aliased_class: self.selectable = from_obj self.adapter = query._get_polymorphic_adapter(self, from_obj) def corresponds_to(self, entity): if _is_aliased_class(entity): return entity is self.path_entity else: return entity.base_mapper is self.path_entity def _get_entity_clauses(self, query, context): adapter = None if not self.is_aliased_class and query._polymorphic_adapters: adapter = query._polymorphic_adapters.get(self.mapper, None) if not adapter and self.adapter: adapter = self.adapter if adapter: if query._from_obj_alias: ret = adapter.wrap(query._from_obj_alias) else: ret = adapter else: ret = query._from_obj_alias return ret def row_processor(self, query, context, custom_rows): adapter = self._get_entity_clauses(query, context) if context.adapter and adapter: adapter = adapter.wrap(context.adapter) elif not adapter: adapter = context.adapter # polymorphic mappers which have concrete tables in their hierarchy usually # require row aliasing unconditionally. if not adapter and self.mapper._requires_row_aliasing: adapter = sql_util.ColumnAdapter(self.selectable, self.mapper._equivalent_columns) if self.primary_entity: _instance = self.mapper._instance_processor(context, (self.path_entity,), adapter, extension=self.extension, only_load_props=query._only_load_props, refresh_state=context.refresh_state, polymorphic_discriminator=self._polymorphic_discriminator ) else: _instance = self.mapper._instance_processor(context, (self.path_entity,), adapter, polymorphic_discriminator=self._polymorphic_discriminator) if custom_rows: def main(context, row, result): _instance(row, result) else: def main(context, row): return _instance(row, None) if self.is_aliased_class: entname = self.entity._sa_label_name else: entname = self.mapper.class_.__name__ return main, entname def setup_context(self, query, context): adapter = self._get_entity_clauses(query, context) context.froms.append(self.selectable) if context.order_by is False and self.mapper.order_by: context.order_by = self.mapper.order_by # apply adaptation to the mapper's order_by if needed. if adapter: context.order_by = adapter.adapt_list(util.to_list(context.order_by)) for value in self.mapper._iterate_polymorphic_properties(self._with_polymorphic): if query._only_load_props and value.key not in query._only_load_props: continue value.setup( context, self, (self.path_entity,), adapter, only_load_props=query._only_load_props, column_collection=context.primary_columns ) if self._polymorphic_discriminator: if adapter: pd = adapter.columns[self._polymorphic_discriminator] else: pd = self._polymorphic_discriminator context.primary_columns.append(pd) def __str__(self): return str(self.mapper) class _ColumnEntity(_QueryEntity): """Column/expression based entity.""" def __init__(self, query, column): if isinstance(column, basestring): column = sql.literal_column(column) self._result_label = column.name elif isinstance(column, attributes.QueryableAttribute): self._result_label = column.key column = column.__clause_element__() else: self._result_label = 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) if c is not column: return if not isinstance(column, sql.ColumnElement): raise sa_exc.InvalidRequestError("Invalid column expression '%r'" % column) # if the Column is unnamed, give it a # label() so that mutable column expressions # can be located in the result even # if the expression's identity has been changed # due to adaption if not column._label: column = column.label(None) query._entities.append(self) self.column = column self.froms = set() # look for ORM entities represented within the # given expression. Try to count only entities # for columns whos FROM object is in the actual list # of FROMs for the overall expression - this helps # subqueries which were built from ORM constructs from # leaking out their entities into the main select construct actual_froms = set(column._from_objects) self.entities = util.OrderedSet( elem._annotations['parententity'] for elem in visitors.iterate(column, {}) if 'parententity' in elem._annotations and actual_froms.intersection(elem._from_objects) ) if self.entities: self.entity_zero = list(self.entities)[0] else: self.entity_zero = None def setup_entity(self, entity, mapper, adapter, from_obj, is_aliased_class, with_polymorphic): self.selectable = from_obj self.froms.add(from_obj) def corresponds_to(self, entity): if _is_aliased_class(entity): return entity is self.entity_zero else: return not _is_aliased_class(self.entity_zero) and entity.base_mapper.common_parent(self.entity_zero) def _resolve_expr_against_query_aliases(self, query, expr, context): return query._adapt_clause(expr, False, True) def row_processor(self, query, context, custom_rows): column = self._resolve_expr_against_query_aliases(query, self.column, context) if context.adapter: column = context.adapter.columns[column] def proc(context, row): return row[column] return (proc, self._result_label) def setup_context(self, query, context): column = self._resolve_expr_against_query_aliases(query, self.column, context) context.froms += list(self.froms) context.primary_columns.append(column) def __str__(self): return str(self.column) log.class_logger(Query) class QueryContext(object): def __init__(self, query): if query._statement: if isinstance(query._statement, expression._SelectBaseMixin) and not query._statement.use_labels: self.statement = query._statement.apply_labels() else: self.statement = query._statement else: self.statement = None self.from_clause = query._from_obj self.whereclause = query._criterion self.order_by = query._order_by if self.order_by: self.order_by = [expression._literal_as_text(o) for o in util.to_list(self.order_by)] self.query = query self.session = query.session self.populate_existing = query._populate_existing self.version_check = query._version_check self.refresh_state = query._refresh_state self.primary_columns = [] self.secondary_columns = [] self.eager_order_by = [] self.enable_eagerloads = query._enable_eagerloads self.eager_joins = {} self.froms = [] self.adapter = None self.options = set(query._with_options) self.attributes = query._attributes.copy() class AliasOption(interfaces.MapperOption): def __init__(self, alias): self.alias = alias def process_query(self, query): if isinstance(self.alias, basestring): alias = query._mapper_zero().mapped_table.alias(self.alias) else: alias = self.alias query._from_obj_alias = sql_util.ColumnAdapter(alias) _runid = 1L _id_lock = util.threading.Lock() def _new_runid(): global _runid _id_lock.acquire() try: _runid += 1 return _runid finally: _id_lock.release()