Oracle Database Features
1. Openness:
Oracle can run (including Windows) on all major platforms, fully supports all industry standard, with fully open strategy, it allows customers to choose the most appropriate solution, full support for developers.
2. Scalability, parallelism:
Oracle Parallel Server by a working group of nodes share the same cluster to scalability Windownt provide high availability and scalability cluster solutions. If you can not meet the needs of WindowsNT, the user can move the database to UNIX. Oracle Parallel Server cluster mechanism for various UNIX platforms have a very high degree of integration.
3. Performance:
Oracle almost the highest performance database, keeping the world record TPC-D and TPC-C under an open platform.
4. Client support and application mode:
Oracle supports multi-level network computing to support a variety of industry standard, you can connect with ODBC, JDBC, OCI-peer network client.
5. Operational:
Oracle RDBMS in terms relative to other more complex, while providing GUI and command line, and the same operation WindowsNT under Unix.
6. Use of:
Oracle has a very long experience in the development, fully backward compatible. Widely recognized and applied, there is no risk.
7. Security:
Oracle received the highest level of ISO certification standards. It provides multi-layer security, including for evaluating risk, to prevent unauthorized disclosure of data, the detection and reporting database activity, and by data-driven embodiment of the security access control data in the control database.
Oracle database works
1 Start the Oracle instances on the database server.
2 application is running in the client user processes, enable Oracle Net Services driver to establish a connection with the server.
3 servers running Oracle Net Services driver, the establishment of a dedicated server process user process execution.
4 client commits the transaction.
5 sql server process to obtain statements and check for similar sql statement shared pool, if there is, then the server process checks the user's access; otherwise assign a new shared sql area analysis and implementation of sql statement.
6 servers obtain the necessary data from the actual data files or SGA.
7 server process to update the data in the SGA, the process will be updated DBWn under certain conditions the data block written to disk, LGWR process records the transaction in the redo log file.
8 If the transaction is successful, the server process sends a message to the application.