Interview Questions and Answers

There are no known performance issues when thousands of users access a single instance of Oracle. In fact, Oracle is designed to handle large numbers of users and transactions as it is scalable by default.

Some best practices for developing web apps using Oracle Application Express include using the built-in security features to control access to the app, using bind variables to avoid SQL injection attacks, and using the built-in report generation features to generate reports on app usage.

There are four different types of reports available in Oracle Application Express: Classic Reports, Interactive Reports, Matrix Reports, and Pivot Grid Reports.

A break field is a field that is used to break up data in a report. For example, if you have a report that contains data for multiple years, you could use a break field to break up the data by year. This would allow you to easily see the data for each year separately.

1. Setup of apex environment
2. SSL configuration
3. USER access
4. Security modal definition
5. ad hoc issue and resolution
6. Patching/Performance

If you are running on an oracle database and you want to build rich web applications with reports, forms, charts, drill downs and dashboards with limited Java experienced developers in a short time frame, Oracle APEX is the most likely candidate for consideration.

APEX is installed on Oracle database (above 9.2 version), starting from Oracle 11g it comes pre-installed with the database. It is comprised of metadata in tables, pl/SQL code, and extensive JavaScript APIs.
The URL request from the browser is translated into appropriate APEX PL/SQL call by either Oracle HTTP Server (Apache) with mod_plsql plugin or Embedded PL/SQL Gateway. This varies by the type of APEX installation on the oracle database. After the data is processed, results are relayed back to the browser as HTML. This cycle happens each time a user requests or submits a page. The application session state is maintained in database tables.
APEX installation can be done in two ways. DBAs are more concerned about it than developers. But this determines how the URL is translated.

• Depending on requirements for the availability of the application, the size of the user population, and other factors you can decide how to divide the development environment from the production environment.
• For certain applications, it is acceptable to combine the development server with the deployment server, as long as the end users understand that sometimes the application is not available.
• Other applications may require two (development and production) or even three (development, test, and production) servers.
• In Application Express applications can be moved from environment to environment using an export and import facility for application definitions.
• With one server available to run the database and Application Express, you can still separate the development version of an application from its production version by using two workspaces accessing separate schemas.
• In this case, one workspace will be used by developers and the other will be the workspace in which the application is deployed in production. We will add a few more Oracle Apex Interview Questions soon.