How to implement objects normalized in the database in object-oriented classes?
In the database, I have a larger table of elements and fewer groups. Each element belongs to one group.
Here's what my database design looks like:
+----------------------------------------+
| Inventory |
+----+------+-------+----------+---------+
| Id | Name | Price | Quantity | GroupId |
+----+------+-------+----------+---------+
| 43 | Box | 34.00 | 456 | 4 |
| 56 | Ball | 56.50 | 3 | 6 |
| 66 | Tin | 23.00 | 14 | 4 |
+----+------+-------+----------+---------+
Totally 3000 lines
+----------------------+
| Groups |
+---------+------+-----+
| GroupId | Name | VAT |
+---------+------+-----+
| 4 | Mini | 0.2 |
| 6 | Big | 0.3 |
+---------+------+-----+
Totally 10 lines
I will use OOP classes in the GUI, where the user can edit items and groups in the inventory. It should also be easy to make calculations with a bunch of items. For calculations, these groups are required, such as VAT.
I will write an Item class, but do I need a Group class? and if I need it, should I store them in a global location or how do I access it when I need it for Item calculations? Is there a design template for this case?