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