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About Oracle Database

Oracle Database is a rclational database with objcct and Extcnsiblc Markup Language (XMI.) capabilities. In a rclational database. all data is stored in tables that are composed of rows and columns. Oracle Database enables you to storę data. update it, and cfficicntly rctricvc it. with a high dcgrcc of performance, reliability. and scalability.

Oracle Database is composed of the following clemcnts:

■The Oracle software that you install on your host Computer ■The database. which is a collection of physical filcs on one or morę disks The database contains uscr data. metadata. and control structurcs. Metadata. or data about the data. is the collection of information on disk that permits Oracle software to manage user data. An ex ample of metadata is the data diclionary.

Control structurcs (such as the control filc and onlinc redo log filcs) ensure the integrily. a\ailability. and recoverability of uscr data.

■The Oracle inslance. which is composed of the following:

-The background processes. which are the operating system processes or threads that perform the work of acccssing. storing. monitoring, and recovering user data, metadata. and control files associated with the database -The shared me mory areas used by the background processes ■Server processes that perform work on bchalf of conncclcd users and applications. and the mc mory and temporary storage used by these processes Server processes parse and execute SQL statements, and retriese and return results to the user or application.

■Oracle Net. which is a software laycr that enables Client applications and Oracle Database locommunicaie over a nelwork. and the Oracle Net listener. which is a process that listens for conncction requests from the network.