mySQL Relational Tables

Question

Say I have 3 tables Products, Orders and Orders Product

Products Table

ID | StockNum | Description | Price
4  | 452SB    | Black       | 45.65
5  | 752SA    | Green       | 17.12


Orders Table

ID  | OrderNum | Total  |
14  | 12312    | 79.89  | 
15  | 12313    | 45.65  | 


Orders Product Table

ID  | OrderID  | Product  | Qty   | 
45  | 14       | 452SB    | 1     |
46  | 14       | 752SA    | 2     |
47  | 15       | 452SB    | 1     |

If product information changes (Price or Description) this would throw off all previous order information, whats the best solution for this?. Also does it make more sense to be storing the product ID instead of the StockNum?

** Update ** Does This Make More Sense? Also everything marked with ID at the end is FK

Products Table

ID | StockNum | ProductDetailsID |
4  | 452SB    | 8                |
5  | 752SA    | 9                |

Products Details Table

ID | Description | Price
8  | Black       | 45.65
9  | Green       | 17.12


Orders Table

ID  | OrderNum | Total  |
14  | 12312    | 79.89  | 
15  | 12313    | 45.65  | 


Orders Product Table

ID  | OrderID  | Product  | Qty   | ProductDetailsID |  
45  | 14       | 452SB    | 1     | 8                |
46  | 14       | 752SA    | 2     | 9                |
47  | 15       | 452SB    | 1     | 8                |