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Fixed #20939 -- Simplified query generation by converting QuerySet to Query.

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Thanks Anssi Kääriäinen for the initial patch and Anssi, Simon Charette,
and Josh Smeaton for review.
This commit is contained in:
Tim Graham 2016-10-28 11:20:23 -04:00 • committed by GitHub
parent 80e742d991
commit 1bc249c2a6
9 changed files with 71 additions and 140 deletions
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58
django/db/models/query.py
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@ -19,9 +19,7 @@ from django.db.models.deletion import Collector
from django.db.models.expressions import F
from django.db.models.fields import AutoField
from django.db.models.functions import Trunc
from django.db.models.query_utils import (
InvalidQuery, Q, check_rel_lookup_compatibility,
)
from django.db.models.query_utils import InvalidQuery, Q
from django.db.models.sql.constants import CURSOR
from django.utils import six, timezone
from django.utils.deprecation import RemovedInDjango20Warning
@ -1114,36 +1112,17 @@ class QuerySet(object):
for field, objects in other._known_related_objects.items():
self._known_related_objects.setdefault(field, {}).update(objects)
def _prepare(self, field):
if self._fields is not None:
# values() queryset can only be used as nested queries
# if they are set up to select only a single field.
if len(self._fields or self.model._meta.concrete_fields) > 1:
raise TypeError('Cannot use multi-field values as a filter value.')
elif self.model != field.model:
# If the query is used as a subquery for a ForeignKey with non-pk
# target field, make sure to select the target field in the subquery.
foreign_fields = getattr(field, 'foreign_related_fields', ())
if len(foreign_fields) == 1 and not foreign_fields[0].primary_key:
return self.values(foreign_fields[0].name)
return self
def _as_sql(self, connection):
"""
Returns the internal query's SQL and parameters (as a tuple).
"""
if self._fields is not None:
# values() queryset can only be used as nested queries
# if they are set up to select only a single field.
if len(self._fields or self.model._meta.concrete_fields) > 1:
raise TypeError('Cannot use multi-field values as a filter value.')
clone = self._clone()
def _prepare_as_filter_value(self):
if self._fields is None:
queryset = self.values('pk')
queryset.query._forced_pk = True
else:
clone = self.values('pk')
if clone._db is None or connection == connections[clone._db]:
return clone.query.get_compiler(connection=connection).as_nested_sql()
raise ValueError("Can't do subqueries with queries on different DBs.")
# values() queryset can only be used as nested queries
# if they are set up to select only a single field.
if len(self._fields) > 1:
raise TypeError('Cannot use multi-field values as a filter value.')
queryset = self._clone()
return queryset.query.as_subquery_filter(queryset._db)
def _add_hints(self, **hints):
"""
@ -1161,21 +1140,6 @@ class QuerySet(object):
"""
return self.query.has_filters()
def is_compatible_query_object_type(self, opts, field):
"""
Check that using this queryset as the rhs value for a lookup is
allowed. The opts are the options of the relation's target we are
querying against. For example in .filter(author__in=Author.objects.all())
the opts would be Author's (from the author field) and self.model would
be Author.objects.all() queryset's .model (Author also). The field is
the related field on the lhs side.
"""
# We trust that users of values() know what they are doing.
if self._fields is not None:
return True
return check_rel_lookup_compatibility(self.model, opts, field)
is_compatible_query_object_type.queryset_only = True
class InstanceCheckMeta(type):
def __instancecheck__(self, instance):