The following Microsoft SQL Server Transact-SQL script demonstrates how to perform millions of updates, in batches of 1000 at a time, on home equity loan accounts without bringing the system to a halt:

use FirstFidelityMasterArchive;

use HomeEquityLoan;

set rowcount 1000

while exists( select 1 from Payment where Cleared = 0 )

begin

  update Payment set Cleared = 1 where Cleared = 0

  waitfor delay '000:00:01'

end

set rowcount 0

-- End of Home Equity Loan Star nightly processing cycle

Related article:

http://www.sqlusa.com/bestpractices/largeupdate/