Welcome, it took the need to implement accounting system applications.
The essence of the system to keep track of: ordering the positions of superintendent and approval of the order of 2 departments, search provider supply, payment accounting, delivery to the warehouse (status), the arrival at the warehouse (notification of the superintendent), and the cost of each position in the order.
Some of the positions require the attachment of the passport.
Providers can be several for one position, there can be multiple invoices from 1 vendor, pre-and post - payment.
Bringing all to the table, the best implementations are not yet invented.
The question how to build a database for faster work. Stored in different tables and link via the ID?
There is a need of filtering on all fields, filter by supplier, search order invoice (an invoice), orders: the object Manager, foreman and other...