If you don't know what i mean, here is a screenshot below. To help you to better understand what is my prob. The screenshot below show the supplies page, it is here that i enter and save data into the database.

And in the image below, the saved items in the supplies page will be use here,

My problem:
I have only 1 problem and that is to get the code for the selected description in the drop-down list box. For example i choose cheese in the description field, and fill up other info, then when i press the save button, the data will be saved in the database and be displayed in the table below. Because i have chosen cheese the code that will appear in the table will be "1211". Because in the supplies page, cheese has the code of 1211.
Any help? Thanks in advance.