How To Set Codes Linked To Products

I am using Access 2010. I have 4 columns in my file. They are "Code", "Item", "Qty", and "Amount" . I have 5 products with my own codes. It means the codes are set by me. For example, 00001 for ruler, 00101 for book, 00201 for pencil, 00301 for rubber, 00401 for pen. My wish is to link the code and product together. It means that when I sell a pen, I must type the code for pen (in the "code column") and I must type pen in "Item Column", so I think it really takes long to do this because I will really make a mistake because the code and item are not linked at all. What I mean is that when I fill or know the code, I will get the product automatically in the "Item Column" or vice versa.

Now I have set the code 00401 for pen.

So when I need to fill the information. I wish to fill the code in the "Code Column" and then the word pen is automatically shown in the "Item Column". In this case, I will be able to get right code linked to its product.