From 290ceecf73524b3d6fa48b8a147c93e3e5243ba7 Mon Sep 17 00:00:00 2001
From: "W. Trevor King" <wking@drexel.edu>
Date: Mon, 2 Apr 2012 10:39:57 -0400
Subject: [PATCH] Don't allow duplicate records for the same CAS number.

---
 chemdb/models.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/chemdb/models.py b/chemdb/models.py
index 5ef57d1..02c1e54 100644
--- a/chemdb/models.py
+++ b/chemdb/models.py
@@ -33,7 +33,7 @@ class NFPASpecial (NamedItem):
 class CASNumber (NamedItem):
     "Chemical Abstracts Service registery number"
     cas = _models.CharField(
-        'CAS#', max_length=20)
+        'CAS#', max_length=20, unique=True)
 
     def clean(self):
         if not _util.valid_CASno(self.cas):
-- 
2.26.2