Author: mtredinnick
Date: 2007-10-13 21:16:38 -0500 (Sat, 13 Oct 2007)
New Revision: 6497
Modified:
django/branches/queryset-refactor/django/db/models/query.py
django/branches/queryset-refactor/django/db/models/sql/datastructures.py
django/branches/queryset-refactor/django/db/models/sql/query.py
django/branches/queryset-refactor/tests/regressiontests/queries/models.py
Log:
queryset-refactor: Made all the changes needed to have count() work properly
with ValuesQuerySet. This is the general case of #2939.
At this point, all the existing tests now pass on the branch (except for
Oracle). It's a bit slower than before, though, and there are still a bunch of
known bugs that aren't in the tests (or only exercised for some backends).
Modified: django/branches/queryset-refactor/django/db/models/query.py
===================================================================
--- django/branches/queryset-refactor/django/db/models/query.py 2007-10-14
02:16:08 UTC (rev 6496)
+++ django/branches/queryset-refactor/django/db/models/query.py 2007-10-14
02:16:38 UTC (rev 6497)
@@ -251,7 +251,7 @@
##################################################
def values(self, *fields):
- return self._clone(klass=ValuesQuerySet, _fields=fields)
+ return self._clone(klass=ValuesQuerySet, setup=True, _fields=fields)
def dates(self, field_name, kind, order='ASC'):
"""
@@ -266,8 +266,8 @@
field = self.model._meta.get_field(field_name, many_to_many=False)
assert isinstance(field, DateField), "%r isn't a DateField." \
% field_name
- return self._clone(klass=DateQuerySet, _field=field, _kind=kind,
- _order=order)
+ return self._clone(klass=DateQuerySet, setup=True, _field=field,
+ _kind=kind, _order=order)
##################################################################
# PUBLIC METHODS THAT ALTER ATTRIBUTES AND RETURN A NEW QUERYSET #
@@ -363,13 +363,15 @@
# PRIVATE METHODS #
###################
- def _clone(self, klass=None, **kwargs):
+ def _clone(self, klass=None, setup=False, **kwargs):
if klass is None:
klass = self.__class__
c = klass()
c.model = self.model
c.query = self.query.clone()
c.__dict__.update(kwargs)
+ if setup and hasattr(c, '_setup_query'):
+ c._setup_query()
return c
def _get_data(self):
@@ -389,16 +391,33 @@
# select_related isn't supported in values().
self.query.select_related = False
+ # QuerySet.clone() will also set up the _fields attribute with the
+ # names of the model fields to select.
+
def iterator(self):
extra_select = self.query.extra_select.keys()
extra_select.sort()
+ if extra_select:
+ self.field_names.extend([f for f in extra_select])
- # Construct two objects -- fields and field_names.
- # 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.
+ for row in self.query.results_iter():
+ yield dict(zip(self.field_names, row))
+
+ def _setup_query(self):
+ """
+ Sets up any special features of the query attribute.
+
+ 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:
- if not extra_select:
+ if not self.query.extra_select:
fields = [self.model._meta.get_field(f, many_to_many=False)
for f in self._fields]
field_names = self._fields
@@ -418,30 +437,42 @@
field_names = [f.attname for f in fields]
self.query.add_local_columns([f.column for f in fields])
- if extra_select:
- field_names.extend([f for f in extra_select])
+ self.field_names = field_names
- for row in self.query.results_iter():
- yield dict(zip(field_names, row))
-
- def _clone(self, klass=None, **kwargs):
+ def _clone(self, klass=None, setup=False, **kwargs):
+ """
+ Cloning a ValuesQuerySet preserves the current fields.
+ """
c = super(ValuesQuerySet, self)._clone(klass, **kwargs)
c._fields = self._fields[:]
+ c.field_names = self.field_names[:]
+ if setup and hasattr(c, '_setup_query'):
+ c._setup_query()
return c
class DateQuerySet(QuerySet):
def iterator(self):
- self.query = self.query.clone(klass=sql.DateQuery)
+ return self.query.results_iter()
+
+ def _setup_query(self):
+ """
+ Sets up any special features of the query attribute.
+
+ Called by the _clone() method after initialising the rest of the
+ instance.
+ """
+ self.query = self.query.clone(klass=sql.DateQuery, setup=True)
self.query.select = []
self.query.add_date_select(self._field.column, self._kind, self._order)
if self._field.null:
self.query.add_filter(('%s__isnull' % self._field.name, True))
- return self.query.results_iter()
- def _clone(self, klass=None, **kwargs):
- c = super(DateQuerySet, self)._clone(klass, **kwargs)
+ def _clone(self, klass=None, setup=False, **kwargs):
+ c = super(DateQuerySet, self)._clone(klass, False, **kwargs)
c._field = self._field
c._kind = self._kind
+ if setup and hasattr(c, '_setup_query'):
+ c._setup_query()
return c
class EmptyQuerySet(QuerySet):
@@ -455,14 +486,14 @@
def delete(self):
pass
- def _clone(self, klass=None, **kwargs):
+ def _clone(self, klass=None, setup=False, **kwargs):
c = super(EmptyQuerySet, self)._clone(klass, **kwargs)
c._result_cache = []
return c
def iterator(self):
# This slightly odd construction is because we need an empty generator
- # (it should raise StopIteration immediately).
+ # (it raises StopIteration immediately).
yield iter([]).next()
# QOperator, QAnd and QOr are temporarily retained for backwards compatibility.
Modified:
django/branches/queryset-refactor/django/db/models/sql/datastructures.py
===================================================================
--- django/branches/queryset-refactor/django/db/models/sql/datastructures.py
2007-10-14 02:16:08 UTC (rev 6496)
+++ django/branches/queryset-refactor/django/db/models/sql/datastructures.py
2007-10-14 02:16:38 UTC (rev 6497)
@@ -32,12 +32,12 @@
"""
Perform a count on the given column.
"""
- def __init__(self, col=None, distinct=False):
+ def __init__(self, col='*', distinct=False):
"""
Set the column to count on (defaults to '*') and set whether the count
should be distinct or not.
"""
- self.col = col and col or '*'
+ self.col = col
self.distinct = distinct
def relabel_aliases(self, change_map):
@@ -49,13 +49,13 @@
if not quote_func:
quote_func = lambda x: x
if isinstance(self.col, (list, tuple)):
- col = '%s.%s' % tuple([quote_func(c) for c in self.col])
+ col = ('%s.%s' % tuple([quote_func(c) for c in self.col]))
else:
col = self.col
if self.distinct:
- return 'COUNT(DISTINCT(%s))' % col
+ return 'COUNT(DISTINCT %s)' % col
else:
- return 'COUNT(%s)' % col
+ return 'COUNT(%s)' % self.col
class Date(object):
"""
Modified: django/branches/queryset-refactor/django/db/models/sql/query.py
===================================================================
--- django/branches/queryset-refactor/django/db/models/sql/query.py
2007-10-14 02:16:08 UTC (rev 6496)
+++ django/branches/queryset-refactor/django/db/models/sql/query.py
2007-10-14 02:16:38 UTC (rev 6497)
@@ -147,15 +147,17 @@
def get_count(self):
"""
- Performs a COUNT() or COUNT(DISTINCT()) query, as appropriate, using
- the current filter constraints.
+ Performs a COUNT() query using the current filter constraints.
"""
- counter = self.clone()
- counter.clear_ordering()
- counter.clear_limits()
- counter.select_related = False
- counter.add_count_column()
- data = counter.execute_sql(SINGLE)
+ obj = self.clone()
+ obj.clear_ordering()
+ obj.clear_limits()
+ obj.select_related = False
+ if obj.distinct and len(obj.select) > 1:
+ obj = self.clone(CountQuery, _query=obj, where=WhereNode(self),
+ distinct=False)
+ obj.add_count_column()
+ data = obj.execute_sql(SINGLE)
if not data:
return 0
number = data[0]
@@ -176,7 +178,6 @@
If 'with_limits' is False, any limit/offset information is not included
in the query.
"""
- qn = self.connection.ops.quote_name
self.pre_sql_setup()
result = ['SELECT']
if self.distinct:
@@ -185,21 +186,12 @@
result.append(', '.join(out_cols))
result.append('FROM')
- for alias in self.tables:
- if not self.alias_map[alias][ALIAS_REFCOUNT]:
- continue
- name, alias, join_type, lhs, lhs_col, col = \
- self.alias_map[alias][ALIAS_JOIN]
- alias_str = (alias != name and ' AS %s' % alias or '')
- if join_type:
- result.append('%s %s%s ON (%s.%s = %s.%s)'
- % (join_type, qn(name), alias_str, qn(lhs),
- qn(lhs_col), qn(alias), qn(col)))
- else:
- result.append('%s%s' % (qn(name), alias_str))
- result.extend(self.extra_tables)
+ from_, f_params = self.get_from_clause()
+ result.extend(from_)
+ params = list(f_params)
- where, params = self.where.as_sql()
+ where, w_params = self.where.as_sql()
+ params.extend(w_params)
if where:
result.append('WHERE %s' % where)
if self.extra_where:
@@ -348,6 +340,30 @@
for alias, col in extra_select])
return result
+ def get_from_clause(self):
+ """
+ Returns a list of strings that are joined together to go after the
+ "FROM" part of the query, as well as any extra parameters that need to
+ be included. Sub-classes, can override this to create a from-clause via
+ a "select", for example (e.g. CountQuery).
+ """
+ result = []
+ qn = self.connection.ops.quote_name
+ for alias in self.tables:
+ if not self.alias_map[alias][ALIAS_REFCOUNT]:
+ continue
+ name, alias, join_type, lhs, lhs_col, col = \
+ self.alias_map[alias][ALIAS_JOIN]
+ alias_str = (alias != name and ' AS %s' % alias or '')
+ if join_type:
+ result.append('%s %s%s ON (%s.%s = %s.%s)'
+ % (join_type, qn(name), alias_str, qn(lhs),
+ qn(lhs_col), qn(alias), qn(col)))
+ else:
+ result.append('%s%s' % (qn(name), alias_str))
+ result.extend(self.extra_tables)
+ return result, []
+
def get_grouping(self):
"""
Returns a tuple representing the SQL elements in the "group by" clause.
@@ -787,8 +803,17 @@
if not self.distinct:
select = Count()
else:
- select = Count((self.table_map[self.model._meta.db_table][0],
- self.model._meta.pk.column), True)
+ opts = self.model._meta
+ if not self.select:
+ select = Count((self.join((None, opts.db_table, None, None)),
+ opts.pk.column), True)
+ else:
+ # Because of SQL portability issues, multi-column, distinct
+ # counts need a sub-query -- see get_count() for details.
+ assert len(self.select) == 1, \
+ "Cannot add count col with multiple cols in 'select'."
+ select = Count(self.select[0], True)
+
# Distinct handling is done in Count(), so don't do it at this
# level.
self.distinct = False
@@ -987,6 +1012,16 @@
else:
self.group_by = [select]
+class CountQuery(Query):
+ """
+ A CountQuery knows how to take a normal query which would select over
+ multiple distinct columns and turn it into SQL that can be used on a
+ variety of backends (it requires a select in the FROM clause).
+ """
+ def get_from_clause(self):
+ result, params = self._query.as_sql()
+ return ['(%s) AS A1' % result], params
+
def find_field(name, field_list, related_query):
"""
Finds a field with a specific name in a list of field instances.
Modified:
django/branches/queryset-refactor/tests/regressiontests/queries/models.py
===================================================================
--- django/branches/queryset-refactor/tests/regressiontests/queries/models.py
2007-10-14 02:16:08 UTC (rev 6496)
+++ django/branches/queryset-refactor/tests/regressiontests/queries/models.py
2007-10-14 02:16:38 UTC (rev 6497)
@@ -111,11 +111,18 @@
>>> Author.objects.filter(Q(name='a3') | Q(item__name='one'))
[<Author: a1>, <Author: a3>]
-Bug #2939
-# FIXME: ValueQuerySets don't work yet.
-# >>> Item.objects.values('creator').distinct().count()
-# 2
+Bug #1878, #2939
+>>> Item.objects.values('creator').distinct().count()
+3
+# Create something with a duplicate 'name' so that we can test multi-column
+# cases (which require some tricky SQL transformations under the covers).
+>>> xx = Item(name='four', creator=a2)
+>>> xx.save()
+>>> Item.objects.exclude(name='two').values('creator',
'name').distinct().count()
+4
+>>> xx.delete()
+
Bug #2253
>>> q1 = Item.objects.order_by('name')
>>> q2 = Item.objects.filter(id=i1.id)
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