Upon login, an application that created a new database for the user and then imported ALL the data from the api before allowing the user to continue to the next

Upon login, an application that created a new database for the user and then imported ALL the data from the api before allowing the user to continue to the next screen. The database would be dropped upon logout. Login times were in the hours if it was successful at all. And now think about the security and data integrity problems that implies.