Unique SKU

I wan’t to create my inventory product with unique sku (Item Code). In this regard I wan’t that when I try to create a product with item code it should be unique. If i try to create an item with a Item Code which already exist then it should warn me and cancel the creation of product.
Will appreciate if someone help me.

Manager does not have the ability to assure unique item codes. You can, however, find and merge duplicates. See the Guide: Find and merge duplicate inventory items | Manager.