You should have a separate table for banking transaction, and a separate one for maintaining the bank name, address, contact that can link to the first one. Looking from your tables above, is that all you have in your ERD?
What about Inventory, Sales and Purchases, don't you think you need a place to store them too? I see you have two tables for voucher, are these for storing payment transaction, if yes, you need to create a referential identifier to your vendor table, and vice-versa for your sales transactions? It's too elaborative to explain further from here, but i do encourage you do find out more on the database structure and designing concepts before you embark further on your project. Derek Liew seems to have some good designing concept for a simple accounting database and you may take a look at it at accountingdes.com