To keep data fresh on Tableau Online there are several different options depending on the data source. There is a section of the Online Help guide that discusses each option for the various data sources.
Also to be clear by completely new database do you mean that it will have a new name and connection information(username and password) each day? Or just the data will be completely updated on the database each day with entirely new data in the same structure?
If you will have new connection information you will need to republish the data source each day. Which could be automated with some programming and use of the Tableau Rest API.
Hope this helps!
No I have not tried this option. Our data is on AWS, and right now I am changing the database name on a daily basis while taking the backup of previous ones. It seems to be working fine.
Thanks for your response. The connection information stays the same, only the database name changes. So, right now I am changing the database name on a daily basis while taking the backup of previous ones.