Unlike other DBMSs, Microsoft Jet stores all database objects in a single file. This file has an .mdb extension and is often referred to as the .mdb file, though it can have any extension. The benefits of a single database file include: easy object management (because all objects can be moved as a single unit), long object names (up to 64 characters), and control over where the individual database objects are located.
Given that the database file contains a variety of objects, its format is quite complex. This section points out some of the characteristics of this file.