DB (Database file)
The DB Database file format
The most common occurrence of files with the DB extension refer to generic database files. Various database programs are able to create such files, open them, and save them in another format. Other occurrences of DB files include a automatically created thumbnail file by Microsoft Windows. This file is usually hidden and bears the name "Thumbs.db". DB files can also be found on mobile devices where it stores various information.
Technical details of DB files
The generic database DB file stores information in a structured way by creating a table. It is similar to a CSV file and can be exported as such in various database programs. The Microsoft Windows thumbs.db file can be deleted, however it will be recreated by Windows automatically once the former location is visited again. This DB file and the one created on mobile devices are usually not meant to be opened or edited. They merely contain support information for the system that created it.