Problem with the search engine or automatically upgrading the categories on the products table

[Miguel Alvarez]

QUESTION: I want that, after uploading the table of products to my Prestashop store, each product will be automatically linked with its categories and subcategories, and the web search engine shows them up, because in this moment it doesn't show them at all.

I cannot automatically link the "categories" column in the product table to the categories (and subcategories) that I have already defined and loaded into the category table itself. Furthermore, in the external view of the store, the search engine does not find the product until I click "Save" ("Guardar" in spanish) within each product.

Curiously, I DO view these categories within each product when I access through the BACKOFFICE. In fact, simply by accesing the product file and clicking "Save/Guardar" it is updated and the search engine goes on and perfectly finds out the product, both in BACKOFFICE itself, and in the store view, where (from the moment the I press "Save/Guardar") and the search starts working.

Is there any mechanism that allows you to update automatically all the products, without having to do it one by one??. 
Is there any automatic procedure that activates the corrrect search engine on the web, after loading the data from the tables?

Thank you all for any help you can provide.