Oracle Examples refers collectively combination of Oracle memory structures (SGA) and the Oracle processes together.
We often say that the Oracle database refers to the Oracle database management system from Oracle database (data storage) the composition and management of the database.
Oracle instance is using the Oracle back-end memory structures (SGA) and processes to manage the oracle database, while providing services.
We can do a popular metaphor, Oracle database management system can be likened to a warehouse, database (physical storage, data files, log files, etc.) is among the cargo warehouse and pocket book. The Oracle instance is responsible for care of the warehouse, to open the door to lock the door of the department responsible for delivery.
Examples of database, including a database background processes (PMON: Process Monitor, SMON: system monitoring, DBWR: read and write the database, LGWR: write log, CKPT: checkpoints and the like), and the SGA memory area (including shared pool: shared pool, db buffer cache: database cache, redo log buffer: redo log buffer, DC: data Dictionary cache, etc.).
Oracle instance is a complex set of operating system processes and memory structures. At any time an Oracle instance can only be associated with a database, you can only enter such a door, like a database repository. However, a database can have multiple instances, it may be more like a warehouse door the same.
Original Address: https: //www.oraclejsq.com/oraclegl/010301278.html