Oracle server

Oracle Database 10g is a relational database management system (RDBMS), which means that it is a set of software programs that handles the storage of information, the security for access to the information, and the connections between various portions of the information.
Once you have installed the RDBMS software, you can create an Oracle instance and a database. Figure 3.1 shows all three of these elements installed on one computer, which is the typical way to install and run the software.The database is made up of datafiles stored on the hard disks of the computer. This is where all of your information will be stored. To add information into the database, you must start up an Oracle instance. Once started, your computer will be running a set of background processes, which manage and manipulate the datafiles, among other things. You also have a memory area called the System Global Area (SGA) that is reserved for Oracle’s use. Oracle stores as much information as possible in its memory to speed up the processing time of whatever operation you do, from retrieving data in a special sorted format (which you will learn how to do in later chapters) to loading data from an online application. The computerthat contains all of these elements is called the database server.