Changeset 475

Timestamp:

08/30/07 16:50:59

Author:

fumanchu

Message:

Improved counting for db SM's.

Files:

• trunk/sandboxes.py (modified) (1 diff)
• trunk/storage/__init__.py (modified) (1 diff)
• trunk/storage/db.py (modified) (2 diffs)
• trunk/test/zoo_fixture.py (modified) (1 diff)

trunk/sandboxes.py

@@ -394 +394 @@
-                    self.view(dejavu.Query(cls, (attr,), expr, **kwargs))])
-    
-
+=None
-        """Number of Units of the given cls which match the given expr."""
-        if cls.identifiers:

trunk/storage/__init__.py

@@ -429 +429 @@
-        return [x for x in self.xview(query, distinct=distinct)]
-    
-
+=None
-        """Number of Units of the given cls which match the given expr."""
-        if cls.identifiers:

trunk/storage/db.py

@@ -34 +34 @@
-
-import geniusql
-
+, logicfuncs
-
-import dejavu
@@ -261 +261 @@
-            for row in data:
-                yield tuple(row)
+    
+    def count(self, cls, expr=None):
+        """Number of Units of the given cls which match the given expr."""
+        if cls.identifiers:
+            uniq = cls.identifiers
+        else:
+            uniq = cls._properties.keys()
+        # TODO: handle multiple args to count()
+        counter = lambda x: [logicfuncs.count(getattr(x, uniq[0]))]
+        
+        query = dejavu.Query(cls, counter, expr)
+        
+        if self.logflags & logflags.VIEW:
+            self.log(logflags.VIEW.message(query, False))
+        
+        data = self.select(query)
+        if data.statement.imperfect:
+            # ^%$#@! There's no way to handle imperfect queries without
+            # creating all involved Units, which defeats the performance
+            # benefits of view.
+            clsname = self.__class__.__name__
+            warnings.warn("The requested query cannot produce perfect SQL "
+                          "with a %s datasource. It may take an absurdly "
+                          "long time to run, since each unit must be fully-"
+                          "formed. %s" % (clsname, query), StorageWarning)
+            return storage.StorageManager.count(self, cls, expr)
+        else:
+            return data.scalar()
-    
-    def multirecall(self, relation, expr):

trunk/test/zoo_fixture.py

@@ -572 +572 @@
-            escapees = box.view((Animal, ['Legs'], f), distinct=True)
-            self.assertEqual(escapees, [(4, ), ])
+            
+            # count should use an aggregate function when using DB's
+            fourlegged = root.count(Animal, lambda x: x.Legs == 4)
+            self.assertEqual(fourlegged, 4)
+            topics = root.count(Exhibit)
+            self.assertEqual(topics, 2)
-            
-            # range should return a sorted list