>Actually I want to use codes to EDIT sale invoice
>
>current sale invoice is as follows
>
>vou_no--code---Product---qty---rate--Amount
>---1-------1401----Apple------10----15----150
>---1-------1402----mango-----20----15----300
>
>
>Now I want to edit current invoice as
>
>vou_no--code---Product---qty---rate--Amount
>---1-------1401----Apple------10----17----170
>---1-------1403----Banana----30----22----660
>
>After editing, I delete current invoice and insert new one on its place with same vou_no.

What is the Primary Key column in the Invoice table? Why do you need to delete and insert instead of simply using UPDATE command?