Making Checkboxes Check If They Exist In A Table?

I'm trying to make checkboxes check if they exist in a table.

What I'm initially trying to do is to list the values is a table e.g. product types, and then if a product has those types assigned to it mark the check box as checked. e.g.

Products Table

Prod No Prod Name

1 Silver Bag

2 Black Bag

3 Red Hat

Product_Types Table

Prod_Type_No Prod_Type_Name

1 Bag

2 Leather

3 Hat

Associated_Product_Types

Prod_No Prod_Type_No

1 1

1 2

2 1

3 3

So When I select product 1 (Silver Bag) it shows 3 check boxes for the product types and prod type 1 and 2 are checked as they exist in the Associated_Product_Types

My problem is I cant figure out how to mark them as checked based on the values in that table.