adding column delete on save

cqlengine/columns.py

@@ -12,6 +12,7 @@ class BaseValueManager(object):
         self.initial_value = value
         self.value = value
 
+    @property
     def deleted(self):
         return self.value is None and self.initial_value is not None
 

cqlengine/models.py

@@ -24,7 +24,7 @@ class BaseModel(object):
             value_mngr = column.value_manager(self, column, values.get(name, None))
             self._values[name] = value_mngr
 
-        #TODO: note any deferred or only fields so they're not deleted
+        #TODO: note any absent fields so they're not deleted
 
     @classmethod
     def column_family_name(cls):
@@ -75,13 +75,16 @@ class ModelMetaClass(type):
     def __new__(cls, name, bases, attrs):
         """
         """
-        #move column definitions into _columns dict
+        #move column definitions into columns dict
         #and set default column names
-        _columns = OrderedDict()
+        columns = OrderedDict()
+        primary_keys = OrderedDict()
         pk_name = None
 
         def _transform_column(col_name, col_obj):
-            _columns[col_name] = col_obj
+            columns[col_name] = col_obj
+            if col_obj.primary_key:
+                primary_keys[col_name] = col_obj
             col_obj.set_column_name(col_name)
             #set properties
             _get = lambda self: self._values[col_name].getval()
@@ -112,7 +115,7 @@ class ModelMetaClass(type):
 
         #check for duplicate column names
         col_names = set()
-        for k,v in _columns.items():
+        for v in columns.values():
             if v.db_field_name in col_names:
                 raise ModelException("{} defines the column {} more than once".format(name, v.db_field_name))
             col_names.add(v.db_field_name)
@@ -128,11 +131,12 @@ class ModelMetaClass(type):
 
         #create db_name -> model name map for loading
         db_map = {}
-        for field_name, col in _columns.items():
+        for field_name, col in columns.items():
             db_map[col.db_field_name] = field_name
 
         #add management members to the class
-        attrs['_columns'] = _columns
+        attrs['_columns'] = columns
+        attrs['_primary_keys'] = primary_keys
         attrs['_db_map'] = db_map
         attrs['_pk_name'] = pk_name
         attrs['_dynamic_columns'] = {}

cqlengine/query.py

@@ -432,7 +432,25 @@ class QuerySet(object):
         cur = conn.cursor()
         cur.execute(qs, field_values)
 
-        #TODO: delete deleted / nulled fields
+        #TODO: delete deleted / nulled columns
+        deleted = [k for k,v in instance._values.items() if v.deleted]
+        if deleted:
+            import ipdb; ipdb.set_trace()
+            del_fields = [self.model._columns[f] for f in deleted]
+            del_fields = [f.db_field_name for f in del_fields if not f.primary_key]
+            pks = self.model._primary_keys
+            qs = ['DELETE {}'.format(', '.join(del_fields))]
+            qs += ['FROM {}'.format(self.column_family_name)]
+            qs += ['WHERE']
+            eq = lambda col: '{0} = :{0}'.format(v.db_field_name)
+            qs += [' AND '.join([eq(f) for f in pks.values()])]
+            qs = ' '.join(qs)
+
+            pk_dict = dict([(v.db_field_name, getattr(instance, k)) for k,v in pks.items()])
+            cur.execute(qs, pk_dict)
+            
+
+
 
     def create(self, **kwargs):
         return self.model(**kwargs).save()

cqlengine/tests/model/test_model_io.py

@@ -10,7 +10,7 @@ from cqlengine import columns
 class TestModel(Model):
     count   = columns.Integer()
     text    = columns.Text()
-    
+
 class TestModelIO(BaseCassEngTestCase):
 
     @classmethod
@@ -54,11 +54,6 @@ class TestModelIO(BaseCassEngTestCase):
         tm2 = TestModel.objects(id=tm.pk).first()
         self.assertIsNone(tm2)
 
-    def test_nullable_columns_are_saved_properly(self):
-        """
-        Tests that nullable columns save without any trouble
-        """
-
     def test_column_deleting_works_properly(self):
         """
         """

cqlengine/tests/query/test_queryset.py

@@ -78,16 +78,6 @@ class TestQuerySetOperation(BaseCassEngTestCase):
         query2 = query1.filter(expected_result__gte=1)
         assert len(query2._where) == 2
 
-    def test_queryset_slicing(self):
-        """
-        Check that the limit and start is implemented as iterator slices
-        """
-
-    def test_proper_delete_behavior(self):
-        """
-        Tests that deleting the contents of a queryset works properly
-        """
-
     def test_the_all_method_clears_where_filter(self):
         """
         Tests that calling all on a queryset with previously defined filters returns a queryset with no filters