Structure Question...

Hi everyone, I'd like to know how you would set up the following: I've set up a MySQL database with 600 products. I set it up where each product belongs to a category. However, now we want to take it further where different products can now belong to more than 1 category. How would you create this? 1. Would you duplicate the records for items that belong to more than 1 category and change the categories in those duplicated records? 2. Would you enter multiple categories into 1 column? 3. Would you create a different database that tracks categories and creat a many to many relationship? Thanks, Doug Coning