No, just on CMDB level is enough, you should check the "BMC Atrium CMDB 7.6.04 Administrator's Guide", it's described page 55.
But what do you want to do actually? Because if you enable "audit" for CMDB for a class (it's at class level), you define then what attribute triggers the audit. So basically or it copies the CI, or it "logs" what has changed.
Hi.. thnx for the reply..yeah i enabled it at attribute level also.. but we also need to enable the audit option for that field in the regular form of also.