[soc2010/query-refactor] Moved has_results (implementation of exists()) onto the compiler, where it belongs.

git-svn-id: http://code.djangoproject.com/svn/django/branches/soc2010/query-refactor@13334 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -493,7 +493,7 @@ class QuerySet(object):
 
     def exists(self):
         if self._result_cache is None:
-            return self.query.has_results(using=self.db)
+            return self.query.get_compiler(self.db).has_results()
         return bool(self._result_cache)
 
     ##################################################

django/db/models/sql/compiler.py

@@ -663,6 +663,20 @@ class SQLCompiler(object):
         self.query.deferred_to_data(columns, self.query.deferred_to_columns_cb)
         return columns
     
+    def has_results(self):
+        q = self.query.clone()
+        q.add_extra({'a': 1}, None, None, None, None, None)
+        q.select = []
+        q.select_fields = []
+        q.default_cols = False
+        q.select_related = False
+        q.set_extra_mask(('a',))
+        q.set_aggregate_mask(())
+        q.clear_ordering(True)
+        q.set_limits(high=1)
+        compiler = q.get_compiler(using=self.using)
+        return bool(compiler.execute_sql(SINGLE))
+
     def results_iter(self):
         """
         Returns an iterator over the results from executing this query.

django/db/models/sql/query.py

@@ -402,20 +402,6 @@ class Query(object):
 
         return number
 
-    def has_results(self, using):
-        q = self.clone()
-        q.add_extra({'a': 1}, None, None, None, None, None)
-        q.select = []
-        q.select_fields = []
-        q.default_cols = False
-        q.select_related = False
-        q.set_extra_mask(('a',))
-        q.set_aggregate_mask(())
-        q.clear_ordering(True)
-        q.set_limits(high=1)
-        compiler = q.get_compiler(using=using)
-        return bool(compiler.execute_sql(SINGLE))
-
     def combine(self, rhs, connector):
         """
         Merge the 'rhs' query into the current one (with any 'rhs' effects