Regarding product categories

Previously

https://www.zen-cart.com/showthread....09#post1336509

If you're asking how to create "linked products" ... you simply have a Products import that duplicates the product's definition, once for each linked category. The final record for the product will contain the category "path" to the product's master-category.
So the field
v_categories_name
is always additive?

If a product already has multiple links and I want to delete those links so only the master category remains in p2c table...?
Is there a way with an import, or I should just use sql?

I would have thought a product should have a column for the master category and another column for additional categories (containing multiple categories) which would replace any already defined...so if empty, remove those defined...?