diff --git a/purchase.py b/purchase.py
index a261f21..b793d51 100644
--- a/purchase.py
+++ b/purchase.py
@@ -204,6 +204,16 @@ class Line(metaclass=PoolMeta):
     stock_quantity = fields.Function(fields.Float('Stock Quantity',
         digits=(16, Eval('default_uom_digits', 2))),
         'on_change_with_stock_quantity')
+    # date_start = fields.Date('Date Start')
+    # date_end = fields.Date('Date End')
+    party = fields.Function(fields.Many2One('party.party', 'Party'), 'get_parent_data')
+    date = fields.Function(fields.Date('Date'), 'get_parent_data')
+
+    def get_parent_data(self, name=None):
+        if name == 'date':
+            return self.purchase.purchase_date
+        if name == 'party':
+            return self.purchase.party.id
 
     @fields.depends('product', 'purchase',
         '_parent_purchase.warehouse')