A Microsoft database engine technology developed in 1992 and included in a variety of Microsoft products, including Microsoft Access and Microsoft Visual Basic. Jet is not available as a separate product.
Jet, which stands for Joint Engine Technology, is an advanced 32-bit multithreaded database engine that uses transaction logs to track and maintain information and provide fault tolerance. The Jet database engine has its own processors for performing client-based processing of queries and for generating result sets. Jet databases can be accessed using Data Access Objects (DAO) and open database connectivity (ODBC). DAO provides the Component Object Model (COM) interface for accessing indexed sequential access method (ISAM) databases such as Microsoft FoxPro, dBASE, or Paradox through Jet. Native Jet database files usually have the extension .mdb. Jet is used by the directory and information store database services of Microsoft Exchange Server.
Jet databases are best accessed through DAO (rather than ODBC) because they expose only a limited amount of functionality to ODBC drivers. Jet cannot use ODBC to build queries that use server-side cursors, and it has limited capability for stored procedures and multiple result sets.