Auto input based on several fields

[Oyseka]

Hi All, I want to put a unique identifier for a barcode on a new products after validating that they do not already exist. The fields are defined as:

Product

Active_Ingredient

Manufacturer

SU_size

Pack_Qty

When inputting a new product to the table these fields are completed and if they do not exist in exactly the same format then an auto enter takes place in the code field. Can anyone assist please