Total Posts: 1770
Hm.. actually it looks like i’m being stuck in previous incarnation of the structure.
It is not that hard as long as you have product entity_ids.
In catalog_product_link add records with these values:
where 5 is id for cross_sell type which is in catalog_product_link_type.
insert into (product_id, linked_product_id, link_type_id) values (@main_product_id, @cross_sell_product_id, 5);
You could add optional position sort order in catalog_product_link_attribute_int, get IDs from catalog_product_link and catalog_product_link_attribute.