Exemplo n.º 1
0
    def _load_for_state(self, state, passive):
        if not state.key:
            return attributes.ATTR_EMPTY

        if passive is attributes.PASSIVE_NO_FETCH:
            return attributes.PASSIVE_NO_RESULT

        prop = self.parent_property
        localparent = state.manager.mapper

        if self.group:
            toload = [
                p.key for p in localparent.iterate_properties
                if isinstance(p, StrategizedProperty) and isinstance(
                    p.strategy, DeferredColumnLoader) and p.group == self.group
            ]
        else:
            toload = [self.key]

        # narrow the keys down to just those which have no history
        group = [k for k in toload if k in state.unmodified]

        session = sessionlib._state_session(state)
        if session is None:
            raise orm_exc.DetachedInstanceError(
                "Parent instance %s is not bound to a Session; "
                "deferred load operation of attribute '%s' cannot proceed" %
                (mapperutil.state_str(state), self.key))

        query = session.query(localparent)
        query._load_on_ident(state.key,
                             only_load_props=group,
                             refresh_state=state)
        return attributes.ATTR_WAS_SET
Exemplo n.º 2
0
    def __call__(self, **kw):
        if kw.get('passive') is attributes.PASSIVE_NO_FETCH:
            return attributes.PASSIVE_NO_RESULT

        state = self.state

        localparent = mapper._state_mapper(state)

        prop = localparent.get_property(self.key)
        strategy = prop._get_strategy(DeferredColumnLoader)

        if strategy.group:
            toload = [
                p.key for p in localparent.iterate_properties
                if isinstance(p, StrategizedProperty)
                and isinstance(p.strategy, DeferredColumnLoader)
                and p.group == strategy.group
            ]
        else:
            toload = [self.key]

        # narrow the keys down to just those which have no history
        group = [k for k in toload if k in state.unmodified]

        if strategy._should_log_debug():
            strategy.logger.debug(
                "deferred load %s group %s", (mapperutil.state_attribute_str(
                    state, self.key), group and ','.join(group) or 'None'))

        session = sessionlib._state_session(state)
        if session is None:
            raise orm_exc.DetachedInstanceError(
                "Parent instance %s is not bound to a Session; "
                "deferred load operation of attribute '%s' cannot proceed" %
                (mapperutil.state_str(state), self.key))

        query = session.query(localparent)
        ident = state.key[1]
        query._get(None,
                   ident=ident,
                   only_load_props=group,
                   refresh_state=state)
        return attributes.ATTR_WAS_SET
    def _clone(self, sess=None):
        # note we're returning an entirely new Query class instance
        # here without any assignment capabilities; the class of this
        # query is determined by the session.
        instance = self.instance
        if sess is None:
            sess = object_session(instance)
            if sess is None:
                raise orm_exc.DetachedInstanceError(
                    "Parent instance %s is not bound to a Session, and no "
                    "contextual session is established; lazy load operation "
                    "of attribute '%s' cannot proceed" %
                    (mapperutil.instance_str(instance), self.attr.key))

        if self.query_class:
            query = self.query_class(self.attr.target_mapper, session=sess)
        else:
            query = sess.query(self.attr.target_mapper)

        query._criterion = self._criterion
        query._order_by = self._order_by

        return query
Exemplo n.º 4
0
    def _load_for_state(self, state, passive):
        if not state.key and \
            (not self.parent_property.load_on_pending or not state.session_id):
            return attributes.ATTR_EMPTY

        instance_mapper = state.manager.mapper
        prop = self.parent_property
        key = self.key
        prop_mapper = self.mapper
        pending = not state.key

        if (
                (passive is attributes.PASSIVE_NO_FETCH or \
                    passive is attributes.PASSIVE_NO_FETCH_RELATED) and
                not self.use_get
            ) or (
                passive is attributes.PASSIVE_ONLY_PERSISTENT and
                pending
            ):
            return attributes.PASSIVE_NO_RESULT

        session = sessionlib._state_session(state)
        if not session:
            raise orm_exc.DetachedInstanceError(
                "Parent instance %s is not bound to a Session; "
                "lazy load operation of attribute '%s' cannot proceed" %
                (mapperutil.state_str(state), key))

        # if we have a simple primary key load, check the
        # identity map without generating a Query at all
        if self.use_get:
            if session._flushing:
                get_attr = instance_mapper._get_committed_state_attr_by_column
            else:
                get_attr = instance_mapper._get_state_attr_by_column

            dict_ = state.dict
            if passive is attributes.PASSIVE_NO_FETCH_RELATED:
                attr_passive = attributes.PASSIVE_OFF
            else:
                attr_passive = passive

            ident = [
                get_attr(state,
                         state.dict,
                         self._equated_columns[pk],
                         passive=attr_passive)
                for pk in prop_mapper.primary_key
            ]
            if attributes.PASSIVE_NO_RESULT in ident:
                return attributes.PASSIVE_NO_RESULT

            if _none_set.issuperset(ident):
                return None

            ident_key = prop_mapper.identity_key_from_primary_key(ident)
            instance = Query._get_from_identity(session, ident_key, passive)
            if instance is not None:
                return instance
            elif passive is attributes.PASSIVE_NO_FETCH or \
                passive is attributes.PASSIVE_NO_FETCH_RELATED:
                return attributes.PASSIVE_NO_RESULT

        q = session.query(prop_mapper)._adapt_all_clauses()

        # don't autoflush on pending
        if pending:
            q = q.autoflush(False)

        if state.load_path:
            q = q._with_current_path(state.load_path + (key, ))

        if state.load_options:
            q = q._conditional_options(*state.load_options)

        if self.use_get:
            return q._load_on_ident(ident_key)

        if prop.order_by:
            q = q.order_by(*util.to_list(prop.order_by))

        for rev in prop._reverse_property:
            # reverse props that are MANYTOONE are loading *this*
            # object from get(), so don't need to eager out to those.
            if rev.direction is interfaces.MANYTOONE and \
                        rev._use_get and \
                        not isinstance(rev.strategy, LazyLoader):
                q = q.options(EagerLazyOption((rev.key, ), lazy='select'))

        lazy_clause = self.lazy_clause(state)

        if pending:
            bind_values = sql_util.bind_values(lazy_clause)
            if None in bind_values:
                return None

        q = q.filter(lazy_clause)

        result = q.all()
        if self.uselist:
            return result
        else:
            l = len(result)
            if l:
                if l > 1:
                    util.warn(
                        "Multiple rows returned with "
                        "uselist=False for lazily-loaded attribute '%s' " %
                        prop)

                return result[0]
            else:
                return None
Exemplo n.º 5
0
    def __call__(self, **kw):
        state = self.state
        instance_mapper = mapper._state_mapper(state)
        prop = instance_mapper.get_property(self.key)
        strategy = prop._get_strategy(LazyLoader)

        if kw.get('passive') is attributes.PASSIVE_NO_FETCH and \
                                    not strategy.use_get:
            return attributes.PASSIVE_NO_RESULT

        if strategy._should_log_debug():
            strategy.logger.debug(
                "loading %s", mapperutil.state_attribute_str(state, self.key))

        session = sessionlib._state_session(state)
        if session is None:
            raise orm_exc.DetachedInstanceError(
                "Parent instance %s is not bound to a Session; "
                "lazy load operation of attribute '%s' cannot proceed" %
                (mapperutil.state_str(state), self.key))

        q = session.query(prop.mapper)._adapt_all_clauses()

        if state.load_path:
            q = q._with_current_path(state.load_path + (self.key, ))

        # if we have a simple primary key load, use mapper.get()
        # to possibly save a DB round trip
        if strategy.use_get:
            ident = []
            allnulls = True
            for primary_key in prop.mapper.primary_key:
                val = instance_mapper.\
                                _get_committed_state_attr_by_column(
                                    state,
                                    state.dict,
                                    strategy._equated_columns[primary_key],
                                    **kw)
                if val is attributes.PASSIVE_NO_RESULT:
                    return val
                allnulls = allnulls and val is None
                ident.append(val)

            if allnulls:
                return None

            if state.load_options:
                q = q._conditional_options(*state.load_options)

            key = prop.mapper.identity_key_from_primary_key(ident)
            return q._get(key, ident, **kw)

        if prop.order_by:
            q = q.order_by(*util.to_list(prop.order_by))

        for rev in prop._reverse_property:
            # reverse props that are MANYTOONE are loading *this*
            # object from get(), so don't need to eager out to those.
            if rev.direction is interfaces.MANYTOONE and \
                        rev._use_get and \
                        not isinstance(rev.strategy, LazyLoader):
                q = q.options(EagerLazyOption(rev.key, lazy='select'))

        if state.load_options:
            q = q._conditional_options(*state.load_options)

        q = q.filter(strategy.lazy_clause(state))

        result = q.all()
        if strategy.uselist:
            return result
        else:
            l = len(result)
            if l:
                if l > 1:
                    util.warn(
                        "Multiple rows returned with "
                        "uselist=False for lazily-loaded attribute '%s' " %
                        prop)

                return result[0]
            else:
                return None