I am fully agreed with mr. Sirdhar Ans.
Vat is applicable on both purchase and sales
TDS is applicable on payment to Job Worker, Salary, Rent,
interest on securities, interest income other than
securities, Payment to contractors, insurance commission,
professional/technical services and payment ot Foreign
Customer master must be created with VAT Registration No. If
the user creates a customer master with same VAT
Registration No. The Systems should a message saying that
VAT Registration No already exists.