Extend table_name to support attributes.

sqlalchemy_utils/functions/__init__.py

@@ -90,14 +90,22 @@ def primary_keys(class_):
             yield column
 
 
-def table_name(class_):
+def table_name(obj):
     """
-    Return table name of given declarative class.
+    Return table name of given target, declarative class or the
+    table name where the declarative attribute is bound to.
     """
+    class_ = getattr(obj, 'class_', obj)
+
     try:
         return class_.__tablename__
     except AttributeError:
+        pass
+
+    try:
         return class_.__table__.name
+    except AttributeError:
+        pass
 
 
 def non_indexed_foreign_keys(metadata, engine=None):

tests/test_table_name.py

@@ -12,7 +12,14 @@ class TestTableName(TestCase):
 
         self.Building = Building
 
-    def test_table_name(self):
+    def test_class(self):
         assert table_name(self.Building) == 'building'
         del self.Building.__tablename__
         assert table_name(self.Building) == 'building'
+
+    def test_attribute(self):
+        assert table_name(self.Building.id) == 'building'
+        assert table_name(self.Building.name) == 'building'
+
+    def test_target(self):
+        assert table_name(self.Building()) == 'building'