Oracle Applications Architecture Overview

Oracle Applications architecture is a multi-tiered distributed computing architecture.In this type or architecture multiple servers are deployed at all the different levels or tiers.
Oracle applications has a 3 tier architecture with 3 different servers providing the specified functionality.
The different Tiers are

1. Desktop Tier
2. Application Tier
3. Database Tier

Oracle Applications Architecture

1. Desktop Tier

The desktop tier is the client interface or the window of the system to the user. This tier is the client interface provided through HTML for HTML based applications and via a java applet for traditional Forms based interface in a web browser.

2. Application Tier
The application tier has a dual role : hosting the various servers and service groups that process the business logic and managing the communication between the desktop tier and database tier.The application tier can is the stage where all the business processing logic resides determining the flow in the system.
Each of the server placed in the application tier has a specific function.

1. Web Server: The Oracle htp server acts as the web server and handles all the requests coming from the desktop clients. It also includes additional components such as Web listener, Java Servlet engine, Java Server Pages. The Web server may service a request itself by running the HTML to construct a simple Web Page or pass the request to the servlet engine which contacts the database server as needed.
2. Forms Server: The Forms Server hosts Oracle Forms . In Oracle Architecture Oracle Forms act as the mediator between the user and the database. They take in the Input from the user through the input fields, process data and store them in the database. Oracle forms are also the window for the user displaying him the data queried by the user. The forms server caches the forms and presents it to the user as and when required
3. Reports Server : The request for an HTML-based report is similar to the flow of any other HTML-based Applications request:
   1. The user clicks the hyperlink of a function from a browser.
   2. The browser makes a URL request to the Web listener.
   3. The Web listener contacts the Reports server through the reports Web CGI. The reports Web CGI allows the user to run reports and see the output through a Web browser.
   4. The Reports server starts the Reports runtime engine.
   5. The Reports runtime engine locates the necessary reports and connects to the database to query the requested information.
   6. The queried information is presented to the user in the form of an HTML page
4. Concurrent Processing Server : The Concurrent Processing Server manages all the concurrent programs submitted by the user to perform some processing. Concurrent Processing server manages all the concurrent programs submitted by the user, scheduling of concurrent processes to be run at a given point in time. The concurrent manager handles all the concurrent programs and makes sure they run separately in the background not hindering any other  processing of oracle applications.
5. Admin Server: The Admin server is located on the node where you maintain the data model and data in your Oracle Applications database.
   You carry out the following operations from this server:
   • Upgrading Oracle Applications.
   • Applying database patches to Oracle Applications

 3. Database Tier

The database tier contains the Oracle database server, which stores all the data maintained by Oracle Applications.More specifically, the database tier contains the Oracle data server files and Oracle Applications database executables that physically store the tables, indexes, and other database objects for your system.The database server does not communicate directly with the desktop clients, but rather

with the servers on the application tier, which mediate the communications between the

database server and the clients

The application tier supports load balancing among many of its servers and services to help provide higher availability,fault tolerance, reliability and optimal scalability.

In the coming blogs we will see the file system used in Oracle and posts related to other topics.