How to correctly implement adding the quantity of goods to the warehouse?

Question

SQL

Hello, not so long ago I began to study this Framework and faced a task in which you need to implement a banal warehouse of office equipment, where there is a warehouse (ID, name of office equipment, quantity in stock). And the second part of it is the receipt of goods from the supplier.

Answer 1

where conditionally there is a warehouse (ID, name of office equipment, quantity in the warehouse).

In fact, there are:
- N receipts of goods in some quantity from some supplier of some number
- M write-offs of goods in some quantity to some recipient of some number,
but the difference between receipts and write-offs - will give the presence in the warehouse, limited by the date - the state of the warehouse on a specific date ...
This is if it is completely simplified.