diff --git a/var.py b/var.py
index 49de2c0..48b9866 100644
--- a/var.py
+++ b/var.py
@@ -196,7 +196,7 @@ with conn:
               
               
     # create nick change table
-    c.execute("CREATE TABLE IF NOT EXISTS nick_changes (old INTEGER, new INTEGER)")
+    c.execute("CREATE TABLE IF NOT EXISTS nick_changes (old INTEGER, new INTEGER, UNIQUE(new))")