Google Shopping and the majority of marketplaces expect to have all the variations of one product.

Each product variation should have:

The parent product must contain all required attributes except those that are different within the product variations, such as size and colour.

Parent products: the showcase products of your product reference. It does not contain any variations. It is not a tangible product – it cannot be purchased. A parent product can be attached to multiple child products.
Child products: these are the products that can be purchased. The child product contains all the aspects that distinguish them from other child products. A child product is attached to one single parent product.

In this case (see image), the parent ID matches the unique identifier of the parent product.

EAN codes and Products Variations