how to maintain day to day Service Rate register....

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VB

SQL-Server-2008R2

i have 3 table named (1) ClassMaster (Classid, ClassName, etc...)
(1) ServiceMaster (serviceid, ServiceName, etc...)
(1) ServiceRateragister (rateid, serviceid,Classid, Rate ,etc) Primary Key(ServiceId,Classid)



using this three table how to maintain My service Rate Register Date to Date
E.g. First i set rate on 01/08/2014
and After 02/08/2014 i set Rate of date 01/09/2014 but it Problem is i add new service on 03/08/2014 so this serviceid not to find in 01/08/2014 its my dependency is i create new register on 03/08/2014 so no problem
Please Help me i set the register 0n 01/08/2014 and i add new service on 02/08/2014 so i set service rate on 01/08/2014


in sort how to i maintain service rate Register Day to Day