1.2 Understanding Oracle Application Express

Oracle Application Express is a hosted declarative development environment for developing and deploying database-centric web applications. Thanks to built-in features such as user interface themes, navigational controls, form handlers, and flexible reports, Oracle Application Express accelerates the application development process.

The Application Express engine renders applications in real time from data stored in database tables. When you create or extend an application, Oracle Application Express creates or modifies metadata stored in database tables. When the application is run, the Application Express engine then reads the metadata and displays the application.

To provide stateful behavior within an application, Oracle Application Express transparently manages session state in the database. Application developers can get and set session state using simple substitutions and standard SQL bind variable syntax.

Oracle Application Express installs with your Oracle database and consists of data in tables and PL/SQL code. Whether you run the Oracle Application Express development environment or run an application built using Oracle Application Express, the process is the same. Your browser sends a URL request that is translated into the appropriate Oracle Application Express PL/SQL call. After the database processes the PL/SQL, the results are relayed back to your browser as HTML. This cycle happens each time you either request or submit a page.

Oracle Application Express does not use a dedicated database connection. Instead, each request is made through a new database session, consuming minimal CPU resources. Application session state is managed in the database tables by the Application Express engine.

Behind the scenes, the Application Express engine renders and processes pages. The Application Express engine also performs these tasks:

• Session state management

• Authentication services

• Authorization services

• Page flow control

• Validation processing

When you install Oracle Application Express, you can install two different environments:

• Runtime environment. In a runtime environment users can run applications but cannot modify them. This is the appropriate choice for production implementations.

• Full development environment. In a full development environment, users can develop, modify, run, and delete Application Express applications. This environment provides complete access to the Oracle Application Express environment described in this document.