Well. I have three tables in this form: the parent comes from a suppliers table and the grid comes from one table that has the supplier's products and another table that has my products catalog.Since any of my products, with a unique codenumber, may come from several different suppliers with a different code number from each this is the reason I need two separate tables. However, some information as the product's description, brand, price is not stored in the supplier's product table to avoid duplication of data.
I have these 3 tables related by a common field that is my codenumber and the grid has fields pertaining to both the products tables.
This is how.

Ulises