Hi all, I have 4 (four) tables using MySql database, ie:

tb_item (
id_item, (varchar) --> PK
item_name, (varchar)
price, (double)

tb_order (
id_order, (varchar) --> PK
id_item, (varchar) -->FK
date_order, (date)
lead_time, (float)
order_quantity, (double)

tb_use (
id_use, (varchar) --> PK
id_item, (varchar) -->FK
date_use, (date)
use_quantity, (double)

tb_inventory (
id_inventory, (varchar) --> PK
id_item, (varchar) --> FK
id_order, (varchar) --> FK
id_use, (varchar) --> FK
item_stock, (double)

My problem is I want to item_stock in tb_inventory automatically updated: when tb_order.order_quantity or tb_use.use_quantity are updated, then tb_inventory.item_stock will updated automatically by using a calculation “tb_order.order_quantity – tb_use.use_quantity = tb_inventory.item_stock” (Example: 10 - 7 = 3).
How to create code for the problem in C#.

Please help, thanks in advance.