Config document generator from database

Hey all. I have this doubt: 

I want to create a document generator that takes people's data from a database. The database is correctly linked to the generator table. The problem is that the database is of people and is constantly updated, so when I generate a certificate, in the sub-table I see the data that is linked from the people database, but when updating the database that data changes as new data may have been added or old data deleted. Is there any way to fix it?

When it comes to data from a single person, it works for me to have a button that creates a record in another table with that data and from that table I generate the certificate. But in this case, since there is more than 1 data, I can't do it like this.

Thank you.