Python django.db.models.sql.query.Query() Examples

def resolve_lookup_into_field(self, model_cls: Type[Model], lookup: str) -> Union[Field, ForeignObjectRel]:
        query = Query(model_cls)
        lookup_parts, field_parts, is_expression = query.solve_lookup_type(lookup)
        if lookup_parts:
            raise LookupsAreUnsupported()

        return self._resolve_field_from_parts(field_parts, model_cls) 

def test_negated_nullable(self):
        query = Query(Item)
        where = query.build_where(~Q(modified__lt=datetime(2017, 1, 1)))
        self.assertTrue(where.negated)
        lookup = where.children[0]
        self.assertIsInstance(lookup, LessThan)
        self.assertEqual(lookup.lhs.target, Item._meta.get_field('modified'))
        lookup = where.children[1]
        self.assertIsInstance(lookup, IsNull)
        self.assertEqual(lookup.lhs.target, Item._meta.get_field('modified')) 

def test_transform(self):
        query = Query(Author)
        with register_lookup(CharField, Lower):
            where = query.build_where(~Q(name__lower='foo'))
        lookup = where.children[0]
        self.assertIsInstance(lookup, Exact)
        self.assertIsInstance(lookup.lhs, Lower)
        self.assertIsInstance(lookup.lhs.lhs, SimpleCol)
        self.assertEqual(lookup.lhs.lhs.target, Author._meta.get_field('name')) 

def test_multiple_fields(self):
        query = Query(Item)
        where = query.build_where(Q(modified__gt=F('created')))
        lookup = where.children[0]
        self.assertIsInstance(lookup, GreaterThan)
        self.assertIsInstance(lookup.rhs, SimpleCol)
        self.assertIsInstance(lookup.lhs, SimpleCol)
        self.assertEqual(lookup.rhs.target, Item._meta.get_field('created'))
        self.assertEqual(lookup.lhs.target, Item._meta.get_field('modified')) 

def test_complex_query(self):
        query = Query(Author)
        where = query.build_where(Q(num__gt=2) | Q(num__lt=0))
        self.assertEqual(where.connector, OR)

        lookup = where.children[0]
        self.assertIsInstance(lookup, GreaterThan)
        self.assertEqual(lookup.rhs, 2)
        self.assertEqual(lookup.lhs.target, Author._meta.get_field('num'))

        lookup = where.children[1]
        self.assertIsInstance(lookup, LessThan)
        self.assertEqual(lookup.rhs, 0)
        self.assertEqual(lookup.lhs.target, Author._meta.get_field('num')) 

def test_simple_query(self):
        query = Query(Author)
        where = query.build_where(Q(num__gt=2))
        lookup = where.children[0]
        self.assertIsInstance(lookup, GreaterThan)
        self.assertEqual(lookup.rhs, 2)
        self.assertEqual(lookup.lhs.target, Author._meta.get_field('num')) 

def clone(self, *args, **kwargs):
        _clone = super(VersionedQuery, self).clone(*args, **kwargs)
        try:
            _clone.querytime = self.querytime
        except AttributeError:
            # If the caller is using clone to create a different type of Query,
            # that's OK.
            # An example of this is when creating or updating an object, this
            # method is called with a first parameter of sql.UpdateQuery.
            pass
        return _clone 

def test_foreign_key_f(self):
        query = Query(Ranking)
        with self.assertRaises(FieldError):
            query.build_where(Q(rank__gt=F('author__num'))) 

def test_foreign_key_exclusive(self):
        query = Query(ObjectC)
        where = query.build_where(Q(objecta=None) | Q(objectb=None))
        a_isnull = where.children[0]
        self.assertIsInstance(a_isnull, RelatedIsNull)
        self.assertIsInstance(a_isnull.lhs, SimpleCol)
        self.assertEqual(a_isnull.lhs.target, ObjectC._meta.get_field('objecta'))
        b_isnull = where.children[1]
        self.assertIsInstance(b_isnull, RelatedIsNull)
        self.assertIsInstance(b_isnull.lhs, SimpleCol)
        self.assertEqual(b_isnull.lhs.target, ObjectC._meta.get_field('objectb')) 

def pre_sql_setup(self):
        """
        If the update depends on results from other tables, munge the "where"
        conditions to match the format required for (portable) SQL updates.

        If multiple updates are required, pull out the id values to update at
        this point so that they don't change as a result of the progressive
        updates.
        """
        refcounts_before = self.query.alias_refcount.copy()
        # Ensure base table is in the query
        self.query.get_initial_alias()
        count = self.query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return
        query = self.query.chain(klass=Query)
        query.select_related = False
        query.clear_ordering(True)
        query._extra = {}
        query.select = []
        query.add_fields([query.get_meta().pk.name])
        super().pre_sql_setup()

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select

        # Now we adjust the current query: reset the where clause and get rid
        # of all the tables we don't need (since they're in the sub-select).
        self.query.where = self.query.where_class()
        if self.query.related_updates or must_pre_select:
            # Either we're using the idents in multiple update queries (so
            # don't want them to change), or the db backend doesn't support
            # selecting from the updating table (e.g. MySQL).
            idents = []
            for rows in query.get_compiler(self.using).execute_sql(MULTI):
                idents.extend(r[0] for r in rows)
            self.query.add_filter(('pk__in', idents))
            self.query.related_ids = idents
        else:
            # The fast path. Filters and updates in one query.
            self.query.add_filter(('pk__in', query))
        self.query.reset_refcounts(refcounts_before) 

def process_rhs(self, compiler, connection):
        from django.db.models.sql.query import Query
        if isinstance(self.rhs, Query):
            if self.rhs.has_limit_one():
                # The subquery must select only the pk.
                self.rhs.clear_select_clause()
                self.rhs.add_fields(['pk'])
            else:
                raise ValueError(
                    'The QuerySet value for an exact lookup must be limited to '
                    'one result using slicing.'
                )
        return super().process_rhs(compiler, connection) 

def __init__(self, lhs, rhs):
        self.lhs, self.rhs = lhs, rhs
        self.rhs = self.get_prep_lookup()
        if hasattr(self.lhs, 'get_bilateral_transforms'):
            bilateral_transforms = self.lhs.get_bilateral_transforms()
        else:
            bilateral_transforms = []
        if bilateral_transforms:
            # Warn the user as soon as possible if they are trying to apply
            # a bilateral transformation on a nested QuerySet: that won't work.
            from django.db.models.sql.query import Query  # avoid circular import
            if isinstance(rhs, Query):
                raise NotImplementedError("Bilateral transformations on nested querysets are not implemented.")
        self.bilateral_transforms = bilateral_transforms 

def pre_sql_setup(self):
        """
        If the update depends on results from other tables, munge the "where"
        conditions to match the format required for (portable) SQL updates.

        If multiple updates are required, pull out the id values to update at
        this point so that they don't change as a result of the progressive
        updates.
        """
        refcounts_before = self.query.alias_refcount.copy()
        # Ensure base table is in the query
        self.query.get_initial_alias()
        count = self.query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return
        query = self.query.chain(klass=Query)
        query.select_related = False
        query.clear_ordering(True)
        query._extra = {}
        query.select = []
        query.add_fields([query.get_meta().pk.name])
        super().pre_sql_setup()

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select

        # Now we adjust the current query: reset the where clause and get rid
        # of all the tables we don't need (since they're in the sub-select).
        self.query.where = self.query.where_class()
        if self.query.related_updates or must_pre_select:
            # Either we're using the idents in multiple update queries (so
            # don't want them to change), or the db backend doesn't support
            # selecting from the updating table (e.g. MySQL).
            idents = []
            for rows in query.get_compiler(self.using).execute_sql(MULTI):
                idents.extend(r[0] for r in rows)
            self.query.add_filter(('pk__in', idents))
            self.query.related_ids = idents
        else:
            # The fast path. Filters and updates in one query.
            self.query.add_filter(('pk__in', query))
        self.query.reset_refcounts(refcounts_before) 

def process_rhs(self, compiler, connection):
        from django.db.models.sql.query import Query
        if isinstance(self.rhs, Query):
            if self.rhs.has_limit_one():
                # The subquery must select only the pk.
                self.rhs.clear_select_clause()
                self.rhs.add_fields(['pk'])
            else:
                raise ValueError(
                    'The QuerySet value for an exact lookup must be limited to '
                    'one result using slicing.'
                )
        return super().process_rhs(compiler, connection) 

def __init__(self, lhs, rhs):
        self.lhs, self.rhs = lhs, rhs
        self.rhs = self.get_prep_lookup()
        if hasattr(self.lhs, 'get_bilateral_transforms'):
            bilateral_transforms = self.lhs.get_bilateral_transforms()
        else:
            bilateral_transforms = []
        if bilateral_transforms:
            # Warn the user as soon as possible if they are trying to apply
            # a bilateral transformation on a nested QuerySet: that won't work.
            from django.db.models.sql.query import Query  # avoid circular import
            if isinstance(rhs, Query):
                raise NotImplementedError("Bilateral transformations on nested querysets are not supported.")
        self.bilateral_transforms = bilateral_transforms 

def resolve_lookup_expected_type(self, ctx: MethodContext, model_cls: Type[Model], lookup: str) -> MypyType:
        query = Query(model_cls)
        try:
            lookup_parts, field_parts, is_expression = query.solve_lookup_type(lookup)
            if is_expression:
                return AnyType(TypeOfAny.explicit)
        except FieldError as exc:
            ctx.api.fail(exc.args[0], ctx.context)
            return AnyType(TypeOfAny.from_error)

        field = self._resolve_field_from_parts(field_parts, model_cls)

        lookup_cls = None
        if lookup_parts:
            lookup = lookup_parts[-1]
            lookup_cls = field.get_lookup(lookup)
            if lookup_cls is None:
                # unknown lookup
                return AnyType(TypeOfAny.explicit)

        if lookup_cls is None or isinstance(lookup_cls, Exact):
            return self.get_field_lookup_exact_type(helpers.get_typechecker_api(ctx), field)

        assert lookup_cls is not None

        lookup_info = helpers.lookup_class_typeinfo(helpers.get_typechecker_api(ctx), lookup_cls)
        if lookup_info is None:
            return AnyType(TypeOfAny.explicit)

        for lookup_base in helpers.iter_bases(lookup_info):
            if lookup_base.args and isinstance(lookup_base.args[0], Instance):
                lookup_type: MypyType = lookup_base.args[0]
                # if it's Field, consider lookup_type a __get__ of current field
                if (isinstance(lookup_type, Instance)
                        and lookup_type.type.fullname == fullnames.FIELD_FULLNAME):
                    field_info = helpers.lookup_class_typeinfo(helpers.get_typechecker_api(ctx), field.__class__)
                    if field_info is None:
                        return AnyType(TypeOfAny.explicit)
                    lookup_type = helpers.get_private_descriptor_type(field_info, '_pyi_private_get_type',
                                                                      is_nullable=field.null)
                return lookup_type

        return AnyType(TypeOfAny.explicit) 

def pre_sql_setup(self):
        """
        If the update depends on results from other tables, we need to do some
        munging of the "where" conditions to match the format required for
        (portable) SQL updates. That is done here.

        Further, if we are going to be running multiple updates, we pull out
        the id values to update at this point so that they don't change as a
        result of the progressive updates.
        """
        refcounts_before = self.query.alias_refcount.copy()
        # Ensure base table is in the query
        self.query.get_initial_alias()
        count = self.query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return
        query = self.query.clone(klass=Query)
        query.select_related = False
        query.clear_ordering(True)
        query._extra = {}
        query.select = []
        query.add_fields([query.get_meta().pk.name])
        super(SQLUpdateCompiler, self).pre_sql_setup()

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select

        # Now we adjust the current query: reset the where clause and get rid
        # of all the tables we don't need (since they're in the sub-select).
        self.query.where = self.query.where_class()
        if self.query.related_updates or must_pre_select:
            # Either we're using the idents in multiple update queries (so
            # don't want them to change), or the db backend doesn't support
            # selecting from the updating table (e.g. MySQL).
            idents = []
            for rows in query.get_compiler(self.using).execute_sql(MULTI):
                idents.extend(r[0] for r in rows)
            self.query.add_filter(('pk__in', idents))
            self.query.related_ids = idents
        else:
            # The fast path. Filters and updates in one query.
            self.query.add_filter(('pk__in', query))
        self.query.reset_refcounts(refcounts_before) 

def pre_sql_setup(self):
        """
        If the update depends on results from other tables, we need to do some
        munging of the "where" conditions to match the format required for
        (portable) SQL updates. That is done here.

        Further, if we are going to be running multiple updates, we pull out
        the id values to update at this point so that they don't change as a
        result of the progressive updates.
        """
        refcounts_before = self.query.alias_refcount.copy()
        # Ensure base table is in the query
        self.query.get_initial_alias()
        count = self.query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return
        query = self.query.clone(klass=Query)
        query.select_related = False
        query.clear_ordering(True)
        query._extra = {}
        query.select = []
        query.add_fields([query.get_meta().pk.name])
        super(SQLUpdateCompiler, self).pre_sql_setup()

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select

        # Now we adjust the current query: reset the where clause and get rid
        # of all the tables we don't need (since they're in the sub-select).
        self.query.where = self.query.where_class()
        if self.query.related_updates or must_pre_select:
            # Either we're using the idents in multiple update queries (so
            # don't want them to change), or the db backend doesn't support
            # selecting from the updating table (e.g. MySQL).
            idents = []
            for rows in query.get_compiler(self.using).execute_sql(MULTI):
                idents.extend(r[0] for r in rows)
            self.query.add_filter(('pk__in', idents))
            self.query.related_ids = idents
        else:
            # The fast path. Filters and updates in one query.
            self.query.add_filter(('pk__in', query))
        self.query.reset_refcounts(refcounts_before) 

def pre_sql_setup(self):
        """
        If the update depends on results from other tables, we need to do some
        munging of the "where" conditions to match the format required for
        (portable) SQL updates. That is done here.

        Further, if we are going to be running multiple updates, we pull out
        the id values to update at this point so that they don't change as a
        result of the progressive updates.
        """
        refcounts_before = self.query.alias_refcount.copy()
        # Ensure base table is in the query
        self.query.get_initial_alias()
        count = self.query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return
        query = self.query.clone(klass=Query)
        query.select_related = False
        query.clear_ordering(True)
        query._extra = {}
        query.select = []
        query.add_fields([query.get_meta().pk.name])
        super(SQLUpdateCompiler, self).pre_sql_setup()

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select

        # Now we adjust the current query: reset the where clause and get rid
        # of all the tables we don't need (since they're in the sub-select).
        self.query.where = self.query.where_class()
        if self.query.related_updates or must_pre_select:
            # Either we're using the idents in multiple update queries (so
            # don't want them to change), or the db backend doesn't support
            # selecting from the updating table (e.g. MySQL).
            idents = []
            for rows in query.get_compiler(self.using).execute_sql(MULTI):
                idents.extend(r[0] for r in rows)
            self.query.add_filter(('pk__in', idents))
            self.query.related_ids = idents
        else:
            # The fast path. Filters and updates in one query.
            self.query.add_filter(('pk__in', query))
        self.query.reset_refcounts(refcounts_before) 

def pre_sql_setup(self):
        """
        If the update depends on results from other tables, we need to do some
        munging of the "where" conditions to match the format required for
        (portable) SQL updates. That is done here.

        Further, if we are going to be running multiple updates, we pull out
        the id values to update at this point so that they don't change as a
        result of the progressive updates.
        """
        self.query.select_related = False
        self.query.clear_ordering(True)
        super(SQLUpdateCompiler, self).pre_sql_setup()
        count = self.query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return

        # We need to use a sub-select in the where clause to filter on things
        # from other tables.
        query = self.query.clone(klass=Query)
        query.bump_prefix()
        query.extra = {}
        query.select = []
        query.add_fields([query.model._meta.pk.name])
        # Recheck the count - it is possible that fiddling with the select
        # fields above removes tables from the query. Refs #18304.
        count = query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select

        # Now we adjust the current query: reset the where clause and get rid
        # of all the tables we don't need (since they're in the sub-select).
        self.query.where = self.query.where_class()
        if self.query.related_updates or must_pre_select:
            # Either we're using the idents in multiple update queries (so
            # don't want them to change), or the db backend doesn't support
            # selecting from the updating table (e.g. MySQL).
            idents = []
            for rows in query.get_compiler(self.using).execute_sql(MULTI):
                idents.extend([r[0] for r in rows])
            self.query.add_filter(('pk__in', idents))
            self.query.related_ids = idents
        else:
            # The fast path. Filters and updates in one query.
            self.query.add_filter(('pk__in', query))
        for alias in self.query.tables[1:]:
            self.query.alias_refcount[alias] = 0 

def pre_sql_setup(self):
        """
        If the update depends on results from other tables, we need to do some
        munging of the "where" conditions to match the format required for
        (portable) SQL updates. That is done here.

        Further, if we are going to be running multiple updates, we pull out
        the id values to update at this point so that they don't change as a
        result of the progressive updates.
        """
        refcounts_before = self.query.alias_refcount.copy()
        # Ensure base table is in the query
        self.query.get_initial_alias()
        count = self.query.count_active_tables()
        if not self.query.related_updates and count == 1:
            return
        query = self.query.clone(klass=Query)
        query.select_related = False
        query.clear_ordering(True)
        query._extra = {}
        query.select = []
        query.add_fields([query.get_meta().pk.name])
        super(SQLUpdateCompiler, self).pre_sql_setup()

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select

        # Now we adjust the current query: reset the where clause and get rid
        # of all the tables we don't need (since they're in the sub-select).
        self.query.where = self.query.where_class()
        if self.query.related_updates or must_pre_select:
            # Either we're using the idents in multiple update queries (so
            # don't want them to change), or the db backend doesn't support
            # selecting from the updating table (e.g. MySQL).
            idents = []
            for rows in query.get_compiler(self.using).execute_sql(MULTI):
                idents.extend(r[0] for r in rows)
            self.query.add_filter(('pk__in', idents))
            self.query.related_ids = idents
        else:
            # The fast path. Filters and updates in one query.
            self.query.add_filter(('pk__in', query))
        self.query.reset_refcounts(refcounts_before)