Network connection in oracle using Oracle Net

Oracle Net is a component of oracle network services. Oracle net enables a network session from a client to an oracle database server. After the network session is established Oracle Net acts a data courier between client and server. Oracle Net is responsible for,

- Establishing connection between client application and oracle database server.
- Maintaining connection between client application and oracle database server.
- Exchanging messages between them.

Connection to oracle database server from client application can be categorized into three topics.

1. Client/Server Application Connections.
2. Web Client Application Connections.
3. Web Client Connections Without an Application Web Server.

1. Client/Server Application Connections:
Oracle Net software component resides on both client and database server.

Client Application like Java client applications access an Oracle database through a Java Database Connectivity (JDBC) Driver, a standard Java interface for connecting from Java to a relational database.

Oracle offers the following drivers,
- JDBC OCI Driver for client side use with an Oracle client installation
- JDBC Thin Driver for client side use without an Oracle installation, particularly
with applets.

Both of JDBC OCI Driver and JDBC Thin driver use Oracle Net to enable connectivity between a client application and an Oracle database.

2. Web Client Application Connections:
This is similar to Client/Server Application connections except that here browser and web server comes into play.

- The browser on the client communicates with the HTTP protocol to a Web server to make a connection request.
- The Web server sends the request to an application where it is processed.
- The application then uses Oracle Net to communicate with an Oracle database server which is also configured with Oracle Net.

3. Web Client Connections Without an Application Web Server:
Without any web server web client can directly communicate with an oracle database. For example java applet. Also oracle database can be configured to accept HTTP protocol, FTP protocol, or WebDAV protocol connections. These protocols are used for connections to Oracle XML DB in the Oracle database instance.

Related Documents
http://arjudba.blogspot.com/2008/08/configure-network-for-oracle-rac.html

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