Changed aggregate syntax according to Mike Bayer's feedback

sqlalchemy_utils/__init__.py

@@ -1,4 +1,4 @@
-from .aggregates import aggregated_attr
+from .aggregates import aggregated
 from .decorators import generates
 from .exceptions import ImproperlyConfigured
 from .functions import (
@@ -55,7 +55,7 @@ __version__ = '0.21.0'
 
 
 __all__ = (
-    aggregated_attr,
+    aggregated,
     batch_fetch,
     coercion_listener,
     defer_except,

sqlalchemy_utils/aggregates.py

@@ -281,28 +281,23 @@ class AggregatedAttribute(declared_attr):
         self,
         fget,
         relationship,
-        expr,
+        column,
         *args,
         **kwargs
     ):
         super(AggregatedAttribute, self).__init__(fget, *args, **kwargs)
         self.__doc__ = fget.__doc__
-        self.expr = expr
+        self.column = column
         self.relationship = relationship
 
-    def expression(self, expr):
-        self.expr = expr
-        return self
-
     def __get__(desc, self, cls):
-        result = desc.fget(cls)
         if not hasattr(cls, '__aggregates__'):
             cls.__aggregates__ = {}
         cls.__aggregates__[desc.fget.__name__] = {
-            'expression': desc.expr,
+            'expression': desc.fget,
             'relationship': desc.relationship
         }
-        return result
+        return desc.column
 
 
 class AggregatedValue(object):
@@ -430,7 +425,7 @@ class AggregationManager(object):
                         class_=class_,
                         attr=key,
                         relationships=list(reversed(relationships)),
-                        expr=value['expression']
+                        expr=value['expression'](class_)
                     )
                 )
 
@@ -451,14 +446,14 @@ manager = AggregationManager()
 manager.register_listeners()
 
 
-def aggregated_attr(
+def aggregated(
     relationship,
-    expression=sa.func.count
+    column
 ):
     def wraps(func):
         return AggregatedAttribute(
             func,
             relationship,
-            expression
+            column
         )
     return wraps

tests/aggregate/test_custom_select_expressions.py

@@ -1,6 +1,6 @@
 from decimal import Decimal
 import sqlalchemy as sa
-from sqlalchemy_utils.aggregates import aggregated_attr
+from sqlalchemy_utils.aggregates import aggregated
 from tests import TestCase
 
 
@@ -13,12 +13,8 @@ class TestLazyEvaluatedSelectExpressionsForAggregates(TestCase):
             id = sa.Column(sa.Integer, primary_key=True)
             name = sa.Column(sa.Unicode(255))
 
-            @aggregated_attr('products')
+            @aggregated('products', sa.Column(sa.Numeric, default=0))
             def net_worth(self):
-                return sa.Column(sa.Numeric, default=0)
-
-            @net_worth.expression
-            def net_worth_expr(self):
                 return sa.func.sum(Product.price)
 
             products = sa.orm.relationship('Product', backref='catalog')

tests/aggregate/test_deep_paths.py

@@ -1,6 +1,6 @@
 from decimal import Decimal
 import sqlalchemy as sa
-from sqlalchemy_utils.aggregates import aggregated_attr
+from sqlalchemy_utils.aggregates import aggregated
 from tests import TestCase
 
 
@@ -13,9 +13,12 @@ class TestDeepModelPathsForAggregates(TestCase):
             id = sa.Column(sa.Integer, primary_key=True)
             name = sa.Column(sa.Unicode(255))
 
-            @aggregated_attr('categories.products')
+            @aggregated(
+                'categories.products',
+                sa.Column(sa.Integer, default=0)
+            )
             def product_count(self):
-                return sa.Column(sa.Integer, default=0)
+                return sa.func.count('1')
 
             categories = sa.orm.relationship('Category', backref='catalog')
 
@@ -69,9 +72,12 @@ class Test3LevelDeepModelPathsForAggregates(TestCase):
             id = sa.Column(sa.Integer, primary_key=True)
             name = sa.Column(sa.Unicode(255))
 
-            @aggregated_attr('categories.sub_categories.products')
+            @aggregated(
+                'categories.sub_categories.products',
+                sa.Column(sa.Integer, default=0)
+            )
             def product_count(self):
-                return sa.Column(sa.Integer, default=0)
+                return sa.func.count('1')
 
             categories = sa.orm.relationship('Category', backref='catalog')
 

tests/aggregate/test_multiple_aggregates_per_class.py

@@ -1,5 +1,5 @@
 import sqlalchemy as sa
-from sqlalchemy_utils.aggregates import aggregated_attr
+from sqlalchemy_utils.aggregates import aggregated
 from tests import TestCase
 
 
@@ -10,13 +10,16 @@ class TestAggregateValueGenerationForSimpleModelPaths(TestCase):
             id = sa.Column(sa.Integer, primary_key=True)
             name = sa.Column(sa.Unicode(255))
 
-            @aggregated_attr('comments')
+            @aggregated(
+                'comments',
+                sa.Column(sa.Integer, default=0)
+            )
             def comment_count(self):
-                return sa.Column(sa.Integer, default=0)
+                return sa.func.count('1')
 
-            @aggregated_attr('comments', sa.func.max)
+            @aggregated('comments', sa.Column(sa.Integer))
             def last_comment_id(self):
-                return sa.Column(sa.Integer)
+                return sa.func.max(Comment.id)
 
             comments = sa.orm.relationship(
                 'Comment',

tests/aggregate/test_simple_paths.py

@@ -1,5 +1,5 @@
 import sqlalchemy as sa
-from sqlalchemy_utils.aggregates import aggregated_attr
+from sqlalchemy_utils.aggregates import aggregated
 from tests import TestCase
 
 
@@ -10,9 +10,9 @@ class TestAggregateValueGenerationForSimpleModelPaths(TestCase):
             id = sa.Column(sa.Integer, primary_key=True)
             name = sa.Column(sa.Unicode(255))
 
-            @aggregated_attr('comments')
+            @aggregated('comments', sa.Column(sa.Integer, default=0))
             def comment_count(self):
-                return sa.Column(sa.Integer, default=0)
+                return sa.func.count('1')
 
             comments = sa.orm.relationship('Comment', backref='thread')