Microsoft Jet Database Engine

The Microsoft Jet Database Engine is a database engine on which several Microsoft products have been built. A database engine is the underlying component of a database, a collection of information stored on a computer in a systematic way. The first version of Jet was developed in 1992, consisting of three modules which could be used to manipulate a database.

JET stands for Joint Engine Technology, sometimes being referred to as Microsoft JET Engine or simply Jet. Microsoft Access and Visual Basic use or have used Jet as their underlying database engine. It has since been superseded for general use, however, first by Microsoft Desktop Engine (MSDE), then later by SQL Server Express. Jet is now part of Microsoft Windows and is no longer a component of Microsoft Data Access Components (MDAC). For larger database needs, Jet databases can be upgraded (or, in Microsoft parlance, "up-sized") to Microsoft's flagship database product, SQL Server.

Over the years, Jet has become almost synonymous with Microsoft Access, to the extent where many people refer to a Jet database as an "Access database".