Oracle Apex Interview Questions and Answers

1.What is Oracle Application Express?

Ans: Oracle Application Express (also called APEX and formerly called HTML DB) is a FREE RAD web development tool. APEX is written using PL/SQL and runs completely inside of a web browser. Apex is an IDE and a runtime environment. You use APEX to write web applications. Users, using their database user ID, log into APEX and run their application from a menu. With the APEX IDE, you can create forms, reports, and charts. All of the normal web widgets are available: radio groups, buttons, drop-down lists, date pickers, etc. You can even integrate your own JavaScript code should you need it. The output from APEX applications can be to the screen or to PDF, Excel spreadsheet, Flash, or even integrated into a web service.

You can use a supplied theme for a consistent look and feel or create your own theme for a personalized feel to your application. The most important thing to remember about Oracle Application Express is that it is designed from the ground up to be tightly integrated with the Oracle Database, to be a fully capable web development environment, and to be easy enough for savvy business users to create or extend applications for themselves.

2.What applications come with APEX?

Ans: The current version of APEX allows you to download pre-packaged applications for you to learn from and/or modify for your own uses. You can currently download (from Oracle’s Technology site):

1. Employee Directory Lookup – This is exactly what it sounds like.
2. Ask The Expert – Q&A Site ala “asktom”.
3. Bug Tracker – Log and track bug reports.
4. Discussion Forum – Threaded chat, user management, and more.
5. Document Library – Multi-user document repository (Word, Excel, etc).
6. Project Issue Tracker – Define, assign, and report project issues.
7. Online Store – Catalog and shopping cart.
8. Software Projects – Project task tracker.

You are by no means limited to this list of projects. An Internet search for
“Oracle APEX projects”
Gets almost 500,000 hits and more are being posted all the time.

3.What are the uses of APEX?

Ans:

1. Builds professional-looking web applications that are both fast and secure. (oracle apex interview questions)

2. Runs on and lives in the Oracle database. APEX framework and metadata are stored in Oracle tables.

3. It is FREE. No licensing required.

4. The fast learning curve for developers to build the application.

5. Deployment of application is as simple as ‘Export and Import’ if hard-coded references of values that change between environments are avoided.

6. A lot of scope for customization of application look and feel.

7. Scalable for high user volume. ATOM, former ORACLE METALINK (before migrated to Flash version), and MANY APPLICATIONS are built using APEX.

8. Can be configured to use Oracle SSO and EBS and user repository.

4. What is ORACLE AFD?

Ans:  Oracle ASM Filter Driver(ASMFD.. It is a kernel module residing in the I/O paths of the Oracle ASM disks. It is an optional one. After completing Grid installation we need to configure the ASMFD to the system. In case if we used oracle ASM lib we need to migrate ASMLIB to ASMFD. Then we need to clean up the oracle ASM lib. Usually when the server restarted the need to rebind the disk devices with oracles, to simplify this the Oracle ASMFD we needed to configure. It will allow only oracle I/O requests and will reject the invalid or non-Oracle I/O requests.

5.What are the advantages of APEX? 

Ans:  The following are the advantages of APEX:

• No license required it is free.
• Building application it is a fast learning curve for developers. We can build web applications that are fast & secure through APEX.
• There is a lot of scope for customization of the application as per our requirement.
• Deployment of application is very simple as “Import & Export”. If any hard code with reference to values varies between environments is avoided.
• Apex Framework & meta-data is stored in Oracle tables. It runs on live Oracle DB’s.

6.How APEX Architecture works?

Ans:  As the APEX is installed on the Oracle database, starting from Oracle 11g it comes pre-installed with the database. It comprises metadata in tables, pl/SQL code, and also extensive JavaScript APIs.

Then the URL request from the browser is translated into an appropriate APEX PL/SQL call by either Oracle HTTP Server (Apache) with mod_plsql plugin or Embedded PL/SQL Gateway. This is varied by the type of APEX installation on the oracle database. After the processing of data, the results are relayed back to the browser as HTML. This cycle takes place every time a user requests or submits a page. Then the application session state is maintained in the database tables.

APEX can be installed in two ways.DBAs are more concerned about it than the developers but this determines how the URL is being translated.

7.What is the cost of APEX and where one can get it?

Ans:  APEX comes pre-installed and it is completely integrated with Oracle Database Express Edition(XE). For all other editions of the Oracle Database, Oracle Application Express comes as a free add-on that can be downloaded and installed. If you chose to “try before you buy”, or since it’s free, “try before you install”, you can also use the hosted APEX Online facility.

This facility allows the user for creating and running complete applications just as he/she would on his/her own equipment.

8.Where can I try APEX?

Ans: As mentioned above, you can sign up for a free account at APEX.ORACLE.COM (Oracle’s hosted Application Express site). When you sign up for an account, you identify the work area name that you want to use and identify an administrator. From there you can create applications and users just as you would on your own hardware and systems.apex.oracle.com is not intended for production systems, it is intended for exploration and testing. For additional hosting companies, check out Oracle. These sites offer varying levels of hosting including free developer access and full application deployment. (E-learning portal).

9.Specify the user through which you connect to the APEX application?

Ans:

Apex_public_use

10.Skills required for APEX developers?

Ans: Basics of PL/SQL & SQL are required & the added advantage would be having skills related to customizing look and feel with Javascript, CSS, HTML.

11.Mention the types of APEX Users?

Ans: Actually, they are divided into 3 they are:

• Developer.

• Instance Administrators.

• Workspace Administrators.

12.How does APEX integrate with the database?

Ans:  Oracle Application Express is truly a database application. The IDE, the menus, and all of the screens you see in APEX are written in PL/SQL. The metadata for all of those screens, reports, and menus are stored in relational tables within the database. When you point your browser at the APEX URL, the Oracle HTTP listener (Apache +mod_plsql or the PL/SQL gateway, depending on database version) receives that call and uses PL/SQL and the metadata stored in database tables to paint the welcome screen.

When you log into APEX you are using an actual database user ID. This user ID is associated with a role (or roles) within the database and these roles determine what access you will have. If you are an administrator, you have access to create users and workspaces. As a developer, you have access to create new applications. If you are configured as an end-user, you will be able to run one or more applications. Oracle Application Express is integrated with the Oracle Database as no environment is. If you need to extend the basic functionality of APEX, there is no need to learn additional languages or links in additional libraries. On rare occasions, you need to extend functionality, you’ll either use SQL for data access or PL/SQL when procedural code is required.

13.What kind of activities you have done for apex as apex dba?

Ans:

• setup of apex environment.
• SSL configuration.
• USER access.
• security modal definition.
• ad hoc issue and resolution.
• patching/Performance.

14.Which are the attachments that are platform-independent and become a part of the template?

Ans: There are several attachments that are part of the template form.

APP STORE:  This is a kind of attachment that comprises of packages as well as procedures that are useful for all the different forms for the purpose of creating toolbars, menus, etc.

APPSDAYPK: This attachment contains packages that are helpful in controlling the applications associated with oracle.

FNDSQF: This attachment has various procedures as well as packages for flex fields, profiles, message dictionary, and also concurrent processing.

CUSTOM: This attachment is helpful in extending the application forms of oracle without causing any modification related to the application code. There are various kinds of customization including zoom.

15.Which scripts need for the registration process for SSO?

Ans: regapps.sql

This is the first of a 3 part series on embedding files in your APEX application. How are APEX Application components stored inside DB?

APEX allows you to embed static web files (CSS, JS, images, etc) into your application. This functionality removes the need to store web files on a web server which is required for some applications.

To upload your file into the application go to Shared Components > Static Files. Click the Create button. On the Create page, you can upload a file and either associate the file to a specific application or no application.

Files associated with a specific application must have a unique filename within its parent application. It can then be referenced (most likely in a page template) using the #APP_IMAGES# substitution string. Ex: #APP_IMAGES#test.js

Files that are not associated with a specific application are available to all the applications within the workspace and can be referenced (most likely in a page template) using the #WORKSPACE_IMAGES# substitution string. Ex: #WORKSPACE_IMAGES#test.js

Files that are added to the application aren’t stored on the webserver. They are stored in the database. For high traffic applications, this may not be a great idea and you may want to look at storing them on a web server.

16. What is the future of Application Express?

Ans: Oracle has made a large commitment to Application Express. In a fairly short time, APEX has made it to version 3.0. Every release makes it easier to use and deploy applications. While recent releases have improved APEX integration with SOA, APEX does not try to compete with jDeveloper or the Oracle Java stack. APEX is the glue that can combine various parts of an enterprise solution into a whole. APEX is the tool of choice to create web-based, database-centric applications. If your business logic is in the database tier, APEX is the way to go. If your logic is in the middle tier or is implemented at the java level, J2EE may be the better choice. APEX take-up has doubled in the past year and thousands of developers are using APEX. Numbers like these ensure a healthy future for APEX. A recent INFOWORLD ARTICLE contains the following:
“We’re going to take out the need to understand the database,” said Mike Hichwa, vice president of software development at Oracle, talking about Application Express 3.1, which is likely to appear before year-end. The next release of the tool will retain its core functionality but will also be more wizard-driven so it’s easier for nonprogrammers to use, he added.
Application Express enables Oracle database users, including those with limited technical skills, to create and manage secure Web applications using only a Web browser. The tool can be used to prototype Web-based applications as well as run those applications supporting tens to thousands of users.
Currently, Oracle estimates that around 100,000 developers are using Application Express on a monthly basis, but the company would like to open up the tool to many more users, Hichwa said. Oracle’s particularly interested in those people who are currently using Microsoft Corp.’s Access database or its Excel spreadsheet or IBM Corp.’s Lotus Notes groupware to develop Web-based applications.

17.Where can I get more information?

Ans: In addition to the OTN forums and community sites, Application Express has a huge following in the blogosphere. Many expert-level resources maintain blogs about APEX. Some particularly well-known blogs are:
SCOTT SPENDOLINI– APEX Guru and owner of Sumner Technologies (an APEX Training, Services, and Consulting company).
PATRICK WOLF– Inside Oracle APEX, Patrick is a long-time Oracle veteran.
DIMITRI GELLIS – Another long-time Oracle vet and co-founder of APEX Evangelists, an APEX-specific company, with John Scott.
JOHN SCOTT– As mentioned above, co-founder of APEX Evangelists, an Oracle ACE, and Application Express Developer of the Year for2006.
You can find all of these and more at the OTN COMMUNITY SITE.

18.What kind of support exists for APEX?

Ans: Application Express has a robust community to help you develop, deliver, and use APEX applications. The first stop for support would be the APEX Forum sat Oracle Technology Network. This active forum provides tips and answers from many experts both inside and outside of Oracle.
Other sites include:
THE APEX WIKI – Wikipedia for the APEX crowd.
APEX STUDIO – Community-created applications available for download.
APEX MAILING LIST – Sign up for info and Q&A.
THE ORACLE APEX COMMUNITY LISTING The list is growing daily.

19.What is the current version of APEX and why should I upgrade?

Ans: Beta version APEX 4.2 is released a couple of weeks back. This new version offers many enhancements. Among the most useful are:
Print to PDF
Users can choose to export their reports and screens to PDF output.
Migrate from MS-Access
Using an export tool and the Access Migration Workbench, you can migrate user applications to APEX.
Calendar Widget
Older versions included a calendar widget but now users can choose between day, week, or monthly calendars.
Improved Page and Region Caches
Caching improves performance.
Application Builder Defaults
The developer can set defaults for wizards to reduce development time (basic themes for development). The benefits of upgrading include performance enhancements and additional usability features for both the developer and the end-user.
Oracle Database 10g Express Edition only supports Oracle APEX version 2.2.

20.How is APEX a RAD Tool?

Ans: Because APEX is so tightly integrated into the database, you can prototype screens while sitting with the user. The Object Browser allows you to create database objects such as tables in addition to viewing those same objects. This allows you to create objects on the fly and then build tables around those objects. The IDE, including the above Table builder, and all applications are run within a browser. Turn-around time is immediate. Because APEX is declarative, you can easily make changes in real-time via the built-in wizards. Because APEX controls session information for you, and because you use the security framework built into the Oracle Database, you can concentration on delivering applications, not on connection configuration and other typical web development time wasters.

21. I have installed Oracle 11g Enterprise Database with a view to using the embedded APEX but don't know how to launch it? 

Ans: Oracle apex by default while installation of oracle DB. But you need to configure the access mechanism to launch the APEX application.
1) Apache (Web Server)
2) Embedded PL/SQL gateway
3) Oracle Listener

22.Which platforms are supported by Oracle Application Express?

Ans:  Oracle Apex works on the following operating systems:
1. Linux x86
2. Mac OS X Server
3. Linux on Power
4. Linux x86-64
5. z/Linux
6. Linux Itanium
7. Solaris x86
8. Solaris Operating System (SPARC) (64 bit)
9. Microsoft Windows (32 -bit)
10. Microsoft Windows (64 -bit Itanium)
11. Microsoft Windows (x64)
12. AIX5L
13. HP-UX PA -RISC
14. HP Tru64 UNIX (Compaq / DEC)
15. HP-UX Itanium

23. How does the developer know in which version they are working?

Ans: Need to check schema name   OR select version_no from apex_release;

24. If you forget the admin password, how will you log in to the apex application?

Ans: We need to call SQL scripts to reset the password  @apxchpwd.sql (this is the same as altering the user username identifies by password)

25.How will you validate apex

Ans:  Utlrp.sql  or
SQL> exec validate_apex; (If your APEX version is 2.0 or above)
OR
SQL> exec validate_htmldb; (If your APEX version is prior to 2.0