Changeset 7230

Timestamp:

03/12/08 07:41:58 (6 months ago)

Author:

mtredinnick

Message:

queryset-refactor: Refactored the way values() works so that it works properly
across inherited models.

Completely by accident, this also allows values() queries to include fields
from related models, providing it is crossing a single-valued relation
(one-to-one, many-to-one). Many-to-many values() fields still aren't supported,
since that requires actual thinking. So this refs #5768.

Files:

• django/branches/queryset-refactor/django/db/models/query.py (modified) (1 diff)
• django/branches/queryset-refactor/django/db/models/sql/query.py (modified) (3 diffs)
• django/branches/queryset-refactor/django/db/models/sql/subqueries.py (modified) (1 diff)
• django/branches/queryset-refactor/docs/db-api.txt (modified) (1 diff)
• django/branches/queryset-refactor/tests/modeltests/many_to_one/models.py (modified) (1 diff)
• django/branches/queryset-refactor/tests/modeltests/model_inheritance/models.py (modified) (3 diffs)

django/branches/queryset-refactor/django/db/models/query.py

@@ -479 +479 @@
-    def _setup_query(self):
-        """
-
+
+
-
-        Called by the _clone() method after initialising the rest of the
-        instance.
-        """
-        # Construct two objects:
-        #   - fields is a list of Field objects to fetch.
-        #   - field_names is a list of field names, which will be the keys in
-        #   the resulting dictionaries.
-        # 'fields' is used to configure the query, whilst field_names is stored
-        # in this object for use by iterator().
-        if self._fields:
-            opts = self.model._meta
-            all = dict([(field.column, field) for field in opts.fields])
-            for field in opts.fields:
-                all[field.name] = field
-            if not self.query.extra_select:
-                try:
-                    fields = [all[f] for f in self._fields]
-                except KeyError, e:
-                    raise FieldDoesNotExist('%s has no field named %r'
-                                % (opts.object_name, e.args[0]))
-                field_names = list(self._fields)
-            else:
-                fields = []
-                field_names = []
+                names = set(self.model._meta.get_all_field_names())
-                for f in self._fields:
-
-
+
-                        field_names.append(f)
-                    elif not self.query.extra_select.has_key(f):
-                        raise FieldDoesNotExist('%s has no field named %r'
-                                % (self.model._meta.object_name, f))
- # Default to all fields.
-fields = self.model._meta.fields
-
-
-local_columns([f.column for f in fields]
+
+# Default to all fields.
+self.model._meta.
+
+fields(field_names
-        self.query.default_cols = False
-        self.field_names = field_names

django/branches/queryset-refactor/django/db/models/sql/query.py

@@ -917 +917 @@
-            self.where.end_subtree()
-
-
+
+
-        """
-        Compute the necessary table joins for the passage through the fields
@@ -940 +941 @@
-                field, model, direct, m2m = opts.get_field_by_name(name)
-            except FieldDoesNotExist:
-
-
-
+
+
+
+
+
+
+
+
+
+
+
-            if not allow_many and (m2m or not direct):
-                for join in joins:
@@ -1103 +1112 @@
-        return not (self.low_mark or self.high_mark)
-
-local_columns(self, column
-
-column names to the select set, assuming they come from
-the root model (the one given in self.model)
-
-for alias in self.tables:
-    if self.alias_map[alias][ALIAS_REFCOUNT]:
-        break
-else:
-alias = self.get_initial_alias(
-self.select.extend([(alias, col) for col in columns]
+fields(self, field_name
+
+(model) fields to the select set. The field names are
+added in the order specified
+
+alias = self.get_initial_alias()
+opts = self.get_meta()
+for name in field_names:
+    u1, target, u2, joins = self.setup_joins(name.split(LOOKUP_SEP),
+        opts, alias, False, False, True
+    self.select.append((joins[-1][-1], target.column)
-
-    def add_ordering(self, *ordering):

django/branches/queryset-refactor/django/db/models/sql/subqueries.py

@@ -161 +161 @@
-        alias = '%s0' % self.alias_prefix
-        query.change_alias(query.tables[0], alias)
-local_columns([query.model._meta.pk.column
+fields([query.model._meta.pk.name
-
-        # Now we adjust the current query: reset the where clause and get rid

django/branches/queryset-refactor/docs/db-api.txt

@@ -596 +596 @@
-    >>> Blog.objects.values('id', 'name')
-    [{'id': 1, 'name': 'Beatles Blog'}]
+
+You can also retrieve values from across ``ForeignKey`` relations by using
+double underscores to separate the field names, just as when calling the
+``filter()`` command. For example::
+
+    >>> Entry.objects.values('blog__name').distinct()
+    [{'name': 'Beatles Blog'}]
-
-A couple of subtleties that are worth mentioning:

django/branches/queryset-refactor/tests/modeltests/many_to_one/models.py

@@ -250 +250 @@
->>> Reporter.objects.filter(article__reporter=r).distinct()
-[<Reporter: John Smith>]
+
+# It's possible to use values() calls across many-to-one relations.
+>>> d = {'reporter__first_name': u'John', 'reporter__last_name': u'Smith'}
+>>> list(Article.objects.filter(reporter=r).distinct().values('reporter__first_name', 'reporter__last_name')) == [d]
+True
-
-# If you delete a reporter, his articles will be deleted.

django/branches/queryset-refactor/tests/modeltests/model_inheritance/models.py

@@ -15 +15 @@
-from django.db import models
-
+#
+# Abstract base classes
+#
+
-class CommonInfo(models.Model):
-    name = models.CharField(max_length=50)
@@ -34 +38 @@
-    class Meta:
-        pass
+
+#
+# Multi-table inheritance
+#
-
-class Place(models.Model):
@@ -228 +236 @@
-u'Demon Puppies'
-
+# The values() command also works on fields from parent models.
+>>> d = {'rating': 4, 'name': u'Ristorante Miron'}
+>>> list(ItalianRestaurant.objects.values('name', 'rating')) == [d]
+True
+
-"""}