Oracle Database
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| Developer(s) | Oracle Corporation |
|---|---|
| Stable release |
12c Release 1 (12.1.0.2) / 22 July 2014
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| Development status | Active |
| Written in | Assembly language, C, C++ |
| Available in | Multilingual |
| Type | ORDBMS |
| License | Proprietary OTN Standard License |
| Website | Oracle RDBMS |
Oracle Database (commonly referred to as Oracle RDBMS or simply as Oracle) is an object-relational database management system produced and marketed by Oracle Corporation.
Larry Ellison and his two friends and former co-workers, Bob Miner and Ed Oates, started a consultancy called Software Development Laboratories (SDL) in 1977. SDL developed the original version of the Oracle software. The name Oracle comes from the code-name of a CIA-funded project Ellison had worked on while formerly employed by Ampex.
An Oracle database system—identified by an alphanumeric system identifier or SID—comprises at least one instance of the application, along with data storage. An instance—identified persistently by an instantiation number (or activation id: SYS.V_$DATABASE.ACTIVATION#)—comprises a set of operating-system processes and memory-structures that interact with the storage. Typical processes include PMON (the process monitor) and SMON (the system monitor). Oracle documentation can refer to an active database instance as a "shared memory realm".
Users of Oracle databases refer to the server-side memory-structure as the SGA (System Global Area). The SGA typically holds cache information such as data-buffers, SQL commands, and user information. In addition to storage, the database consists of online redo logs (or logs), which hold transactional history. Processes can in turn archive the online redo logs into archive logs (offline redo logs), which provide the basis for data recovery and for the physical-standby forms of data replication using Oracle Data Guard.
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