AbleCommerce Shopping Cart Software

I was getting the following error on my product display page: [[ConLib:Custom/SG_BuyProductDialog]] Item has already been added. Key in dictionary: 'Name' Key being added: 'Name'. It turns out I had added duplicate entries in ac_ProductTemplateFields when I was running a SQL script to update some product templates. For example, I found the following two records in ac_ProductTemplateFields:

• ProductTemplateFieldId, ProductId, InputFieldId, InputValue
• 216, 129, 154, sg
• 305, 129, 154, sg

I'm pretty sure this can't happen via the Admin interface but I was surprised that the table didn't have a unique constraint on it to prevent this from happening. I looked further and found that other than primary keys, the only tables with additional indexes are ac_CatalogNodes, ac_OrderItems, ac_PageViews and ac_Products.

For performance reasons, I could understand not having additional unique constraints on basket or order tables but a table like ac_producttemplatefields is really only used by admin and shouldn't cause any performance hit (other than database size). There are probably other tables that could have unique constraints applied.

• Am I correct that ac_ProductTemplateFields should not have duplicate entries as described above?
• Are there reasons why unique constraints should not be applied to various tables in the system?

Thanks.