Here are the steps to migrate your products from Zen Cart to Big Commerce. (This information can probably be used to migrate from OSCommerce as well.)  It’s a little tricky to do smoothly. The basic process is to create a CSV file from your Zen Cart database then use the Import Products feature in BigCommerce. The tricky part ,of course, is to create the CSV file properly. It’s best to get your data organized in Zen Cart before creating the CSV file. NOTE: I wrote this for BigCommerce V6. The current V7 does not have a option import feature.

1. Product names need to be unique. In Zen Cart, you can have two products with the same name. Big Commerce uses the product name to identify the product.
If you have access to a SQL query tool like PHPmyadmin, you can use the following SQL query to check for duplicate names in Zen Cart:

select * from
products_description pd,
(
SELECT products_id, products_name,
COUNT(products_name) AS NumOccurrences
FROM products_description
GROUP BY products_name
HAVING ( COUNT(products_name) > 1 )
)x
where pd.products_name = x.products_name

2. All products need SKUs. While SKUs or product model IDs are optional in Zen Cart they are required in the import process by Big Commerce. I find that it’s good to have unique SKUs for products.
If you have access to a SQL query tool like PHPmyadmin, you can use the following SQL query to check for duplicat SKUs in Zen Cart:

select * from
products p,
(
SELECT products_id, products_model,
COUNT(products_model) AS NumOccurrences
FROM products
GROUP BY products_model
HAVING ( COUNT(products_model) > 1 )
)x
where p.products_model = x.products_model

3. Category names are mandatory for importing to BigCommerce.

4. Image files are best imported to Big Commerce using the URL of image on the live Zen Cart site. This is a very nifty feature. I first tried importing all images using FTP but it’s a pain and unnecessary.

Importing Variations. Zen Cart calls them attributes. Big Commerce calls them variations or options in V7.

I had trouble when I imported the Variation CSV file. I had an option of “None” appear in BC with all products that had a variation. This is because the
“Force user to select variation option” checkbox was not checked. Unfortunately there is no way to force this in the import file

Don’t import variations with only one option. You can but BigCommerce with force you to create another if you try to modify the option later. Use Excel =COUNTIF(A$2:A$9999,A2) to count variations in your CSV file .

BigCommerce variations import still needs a lot of work.

–to be continued. This is a work in progress. I’m writing this to help others make an easier transition from Zen Cart to Big Commerce.