Embedded Databases: Data Management for Real-Time and Embedded Systems

The term embedded database was coined in the 1980s to mean a database management system (DBMS) that is embedded into an application, in contrast to large central databases (nowadays, usually client/server DMBSs a la Oracle). The first embedded databases had little or nothing to do with embedded systems, which were largely 8-bit, or possibly 16-bit, devices that performed a very specific function. Any data processing requirements were promoted to a higher layer in the system architecture. Embedded systems, like all other facets of computing, have matured and gained faster (32-bit) processors, memory, and more complexity. This has further confused conversations about embedded systems and embedded databases. Today, the term embedded database encompasses databases embedded into software applications, as well as the more modern client/server database design (although embedded client/several varieties are much smaller than their enterprise-level DBMS cousins such as Oracle or DB2). In fact, while embedded databases comprise a sizeable chunk of the overall database market, they show remarkable diversity in important respects such as programming interfaces, storage modes, and system architecture. This article examines some of these differences to help in choosing the right embedded database system for a given project.