Hi Venkata ,
In case of serial numbers, if user deletes any existing record from table, then Serial number will not be updated and seems confusing (like some entries missing). So, instead of serial numbers I suggest to add additional fields like time and date and assign SY-UZEIT and SY-DATUM to those fields respectively and make them Primary keys. So, that in this case user need not to enter any additional values other than required.
I hope this may help you.
Thanks ,
S.Rajendranath Raparthi.
