Ideally you need the three things you back up in a site as documented in https://docs.moodle.org/310/en/Site_backup to restore it https://docs.moodle.org/310/en/Site_restore. But very important: They need to be from the same consistent state of the site. So the database from today and the moodledata directory from yesterday won't do, if the site has been active today.
That said, the experts here know tricks to recover with a bit less. The big warning is though: Don't do more damage trying to recover in a hurry!
That said, the experts here know tricks to recover with a bit less. The big warning is though: Don't do more damage trying to recover in a hurry!