One of the user in Notes 6 forum asked how to keep unique records in the view. I have given very simple solution , In view's advanced tab try to check "Generate unique keys in Index" check box. 
I have noticed still people thinks this option is only for ODBC. But believe me it works well to keep unique records in the view. Hidden tips :)
Here is the conversation ,
http://www-10.lotus.com/ldd/nd6forum.nsf/DateAllThreadedweb/18649ca58a9bddf78525756600158a03?OpenDocument
Posts
February 23, 2009 at 9:34 PM
This will work and I used it a lot of times. But I remember that I sometimes ran into a "64k" error when there were plenty of view entries. So be careful when using this option.
February 23, 2009 at 11:13 PM
Ulrich,
You are right IBM doesn't provide this option for such common use. First if your view having duplicate documents , It means your application is not designed properly.By enabling this option definitely you will face performance issue. This option mainly used to push unique documents into ODBC when view is mapped with Db2.