update statement

hi all

UPDATE zinv_header SET

run_number = '1000000000' "loc_runnumber

invoice_core = '111111

invoice_created = '111112'

invoice_error = '121111'

username = sy-uname

systemdate = sy-datum

systemtime = sy-uzeit .

the above statement is not working, i don no y.i cannot give where condition , bcoz there r no records in the table., Its a great head ache for me.

YOUR HELP needed.

Regards

karthik