Hi @Fulvio
Thanks for the question. The ACF framework is not built to save multiple values to the DB for each field, only one.
The repeater field can handle multiple values because it adds an extra level of logic. This is why it is a premium add-on.
I would advise that you think about using a custom DB table to save all the data to. That way, you have full controll over the SQL.
Your field file has a function called update_value. This is where you can do custom SQL.
Also, the load_value function will allow you to read in the data through custom SQL.
Hope that helps.
Thanks
E
