Effdate d && effective date taxrate n(5,2) && tax rate records in taxmaster.dbf && no of records can change in taxmaster.dbf Effdate Taxrate 01.04.2007 0.00 15.06.2007 4.00 01.07.2007 12.50 schild.dbf have 6 fileds && more than 5000 records with diffrent billdates. billdate d billno c(8) product c(50) quantity n(10,3) rate n(10,2) taxrate n(5,2) billdate billno product quantity rate taxrate 02.04.2007 001001 abc 5 500.00 ?? should be 0.00 03.04.2007 001001 abc 5 500.00 ?? should be 0.00 04.04.2007 001001 abc 5 500.00 ?? should be 0.00 05.05.2007 001001 abc 5 500.00 ?? should be 0.00 04.06.2007 001001 abc 5 500.00 ?? should be 4.00 05.06.2007 001001 abc 5 500.00 ?? should be 4.00 08.06.2007 001001 abc 5 500.00 ?? should be 4.00 10.07.2007 001001 abc 5 500.00 ?? should be 12.50 12.07.2007 001001 abc 5 500.00 ?? should be 12.50 18.07.2007 001001 abc 5 500.00 ?? should be 12.50 21.07.2007 001001 abc 5 500.00 ?? should be 12.50 25.07.2007 001001 abc 5 500.00 ?? should be 12.50i want to update taxrate in schild.dbf from taxmaster.dbf as per billdate.