Database design for multiple units and pricing for each item

table products
id_product | name | ....
1 | abcd | ....
table prices
id_price | Amount | price_type | price
1 | 20 | Discount | 20
table unit
id_unit | fromUnit | Factor | toUnit
1 | Cardboard | 8 | pkt
2 | pkt | 24 | units

I design a database for the commercial business. Basically, each product can have multiple product and price plans.

For example, item A can be sold in carton or pkt, and a default conversion value is specified in.


  1. The user can order in a carton of 192 units or in a carton
    which corresponds to 24 units.

  2. When the user receives the article, the article may be in a different format. For example, order in pkt but received in carton.

I will always convert and save the received uom so I can track it in my inventory.

Any suggestions on how to design my database and link the table based on multiple unit cases and multiple product prices? Many Thanks.