Importing Excel / Updating Products

Hi,

I've recently used NOP Commerce and found the product great.
I wrote a .Net application to take a bunch of XML files from a drop shipping site and turn them into an excel file to import into version 2.30 of your store.

The import works great but I wondered if within the Excel file there is a way to perform an update instead of an import.

I've tried to locate if a particular field enables an update (sku etc) but it still seems to insert a new product + variant.

I can code a db interface to talk direct to the database but would prefer to keep working via one master excel file as it may be better for my customers in the future.

Many thanks in advance

Lee

SKU

                    var productVariant = _productService.GetProductVariantBySku(sku);
                    if (productVariant != null)
                    {... update
                    else
                    {... insert

Many thanks .... You are correct.

It turned out to be that my excel file didn't have the ' at the start of the field to define the column as a string.
Subsequently the sku number wasn't imported to do the matching. Doh! Thanks