diff --git a/rattail/db/extension/model.py b/rattail/db/extension/model.py
index ae97b240874f5e4559170f608e639307aff476e3..110f3736ff094bce267e6c1e459af600693e3e7c 100644
--- a/rattail/db/extension/model.py
+++ b/rattail/db/extension/model.py
@@ -808,6 +808,7 @@ class Product(Base):
     subdepartment = relationship(Subdepartment)
     category = relationship(Category)
     brand = relationship(Brand)
+
     costs = relationship(ProductCost, backref='product',
                          collection_class=ordering_list('preference', count_from=1),
                          order_by=ProductCost.preference)
@@ -834,6 +835,26 @@ Product.current_price = relationship(
     lazy='joined',
     post_update=True)
 
+Product.cost = relationship(
+    ProductCost,
+    primaryjoin=and_(
+        ProductCost.product_uuid == Product.uuid,
+        ProductCost.preference == 1,
+        ),
+    uselist=False,
+    viewonly=True)
+
+Product.vendor = relationship(
+    Vendor,
+    secondary=ProductCost.__table__,
+    primaryjoin=and_(
+        ProductCost.product_uuid == Product.uuid,
+        ProductCost.preference == 1,
+        ),
+    secondaryjoin=Vendor.uuid == ProductCost.vendor_uuid,
+    uselist=False,
+    viewonly=True)
+
 
 class EmployeeEmailAddress(EmailAddress):
     """