Database tier
The Database tier contains the Oracle Database Server which store all the data needed by Oracle Applications.The database server communicates with middle tier and does not communicate directly with the desktop tier.
Desktop tier
Oracle Applications/E-Business Suite is built on three tier Architecture with first Desktop Tier ic client machines accessing applications via browser(HTML based Self service applications) or Java Applet(Jinitiator) for Form based interface.
The componants required on the desktop tier are Forms Client Applet and Oracle Jinitiator.
a. Forms Client Applet:
Most of the Oracle Applications is based on Oracle Forms and Reports and to display oracle forms on a client’s browser an applet is used. This forms client applet displays Oracle Applications screens and support field level validation, multiple windows and list of values (LOVs). The forms client applet is paclaged as Java Archive (JAR) files that contain all java classes for forms applet. These jar files are downoaded from Web server at the beginning of the client’s session and remains in the cache known as Jcache.
b. Oracle Jinitiator:
The Forms Client Applet must run within a Java Virtual Machine (JVM) on the client machine. For Oracle Apps the JVM is provided by Oracle Jinitiator which acts as a plug-in (Active X componant in IE) in the web browser. Please note that for Oracle apps we do not use other JVMs e.g. Microsoft JVM, Sun JVM etc..
When end-user enters the desired Oracle Applications signon URL withing the web browser, the browser will execute the Oracle Jinitiator. If Jinitiator has not been previously installed, end user will be prompted to download the necessary installation executable to the desktop. Once Jinitiator is installed, the forms client applet is started and Oracle Forms sessions is opened.
Application Tier :
This Tier is sometimes referred to as middle tier and provided business logic and code processing. There are six servers in Applications tier:
a. HTTP server
b. Forms server
c. Concurrent Processing Server
d. Reports Server
e. Admin Server
f. Discoverer Server .
Web Server:
listens for HTTP requests and provides an HTTP response to the client. The HTTP response usually consists of an HTML document, but can also be a raw file, an image or some other type of document
Concurrent Processing Server:
The concurrent managers read these requests in the table and start the relevant concurrent programs;
Administration Server:
contains scripts which are used to administer the Oracle Applications eBusiness Suite. From this server the following operations can be performed:
Forms server:
includes the Forms listener and the Forms Runtime Engine. The Forms Runtime Engine maintains a connection to the database on behalf of the Java client. It uses the same Forms, Menus, and Libraries files that are used for running in client/server mode. No application code changes are required to deploy a legacy client/server application to the Internet;
Reports Server:
Run Oracle Applications reports and is always installed on the same node as the Concurrent Processing Server. However the reports are administered separately from the concurrent processing reports;
Discoverer Server :
Discoverer Server is installed if Oracle Discoverer will be used.
