Unique Product SKU

[CyComodo]

Hi!

In my shop every product has unique SKU.
Is there any way to add rule that I can't add same product twice ?
In my old system it shows notification: " This product SKU is already in use"
I would like to use this principle in Virtuemart also.

[balai]

Hi

Use your phpMyadmin to edit the table virtuemart_products and set the field "product_sku" to unique

[CyComodo]

Thank you very much, it works.
But it has weird error. I created new product with used SKU to test it. Yes it shows error but also it clear out all the fields.
This is bad when I write long product description and accidentally add used SKU then Virtuemart clear all and I must refill  the fields.
Is this problem  repairable?