On Apr 13, 2008, at 10:16 AM, Frank Tsao wrote:
> Thank you everyone, I have found out the solution which is
> "validates_uniqueness_of". The statement as below,
>
>
> validates_uniqueness_of :A, :scope => :B
>
>
>
> Frank
> --  
> Posted via http://www.ruby-forum.com/.
>

bit more on the topic

http://pezra.barelyenough.org/blog/2007/11/activerecord-race-conditions/

a @ http://codeforpeople.com/
--
we can deny everything, except that we have the possibility of being  
better. simply reflect on that.
h.h. the 14th dalai lama