Store Mappnig is used to control permissions for your website
Store Mapping import templates supprot keys from entity that you are using mapping for.
Your entity key must be unique. If you have two products with same Name fields, you will not be able to use Name as entity key.
If you don't have Store Mapping set up for this product/category/manufacturer, all stores would show this product. If you set up any restrictions, all, except stores with TRUE value, will not have access.
This is an example table for ACL Mapping of Product
With the import above being the only Store mapping rules that are set up for products with SKU 001, 002 and 003, the following scenario would be executed. 1. Store 1 and 2 would have product 001. No other store would have it. 2. Only store 2 would have product 002. 3. No store would have product 003.