An Oracle database is a collection of data treated as a unit. The purpose of a database is to store and retrieve related information. A database server is the key to solving the problems of information management. In general, a server reliably manages a large amount of data in a multiuser environment so that many users can concurrently access the same data. All this is accomplished while delivering high performance. A database server also prevents unauthorized access and provides efficient solutions for failure recovery.
Oracle Database is the first database designed for enterprise grid computing, the most flexible and cost effective way to manage information and applications. Enterprise grid computing creates large pools of industry-standard, modular storage and servers. With this architecture, each new system can be rapidly provisioned from the pool of components. There is no need for peak workloads, because capacity can be easily added or reallocated from the resource pools as needed.
Below is the step how Oracle db is working
1- an instance has started on computer running oracle
2- a computer running an application in a user process.The client application attempt to establish a connection to the instance by using the oracle net
3- the instance detect the connection request from the application and connect to the server process on behalf of the user process
4- the user update the row
5- the server process receives the statement and check if it is already in the shared pool of the SGA (System Global Area).The server process check the user’s access privilegaÂ to the request data if shared SQL area is found
6- The servers process the any necessary data values from the actual data file or from data block that are store in the SGA.
7- The server process modifies the table data in the SGA.
8- When the transaction is commited,the LGWR process immidiately records the transaction in the redo log file.
9- The DBWn process writes modified block to the disk when doing so is efficient.
10- the servers process sends a success error message across the network to the application.