1. What are the uses of APEX?

Answer:

1. Builds professional looking web applications that are both fast and secure.

2. Runs on and lives in Oracle database. APEX framework and meta data are stored in Oracle tables.

3. It is FREE. No licensing required.

4. Fast learning curve for developers to build 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. Lot of scope for customization of application look and feel.

7. Scalable for high user volume. ASKTOM, 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 fnd user repository.

2. What applications come with APEX?

Answer:

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 (form 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, Exce, 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. Where can I try APEX?

Answer:

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 the Oracle. These sites offer varying levels of hosting including free developer access and full application deployment.

4. What is APEX and what is it used for?

Answer:

APEX is an object-oriented programming language and is a proprietary language which is strongly typed and was developed by Salesforce. It will be used to develop the products in Salesforce to perform transaction control statements and flow execution operations. The APEX’s syntax is similar to Java and can be used in web service requests.

5. What is the architecture of APEX?

Answer:

This is the common APEX Interview Questions asked in an interview. The architecture of the APEX will involve an application server, data storage where the network will be connected to the internet and the end users and developer users will be involving in the different web server requests and compilation errors and validations. The platform application server compiles the source code into a sequence of instructions and will be interpreted by Apex interpreter. The execution of the triggers will be done by the end users. There will be no delay in the web service request to the application server platform.

6. What does the APEX development environment contain?

Answer:

The Salesforce APEX development environment has different features and processes to be followed in order to successfully develop an application and also to set up and edition as per the requirement of the entity. The code can be developed either in a local developer edition or a sandbox of Salesforce. As per the standards, the code will usually be developed in Sandbox and will be deployed into production. The different operations those will be performed during the development of the code is developing the code and its compilation process, debugging the code, testing the code and application, performing the SOQL query execution and its efficiency, color coding, auto alignment and auto-completion of the build process. The main step of executing the code in Salesforce will include the login action into Salesforce sandbox or console before performing these operations.

7. Who uses APEX?

Answer:

If you are running on oracle database and you want to build rich web application 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.

8. What is Apex Interface?

Answer:

If you are running on oracle database and you want to build rich web application 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.

9. What is Apex Scheduler?

Answer:

It is the essential feature which is utilized just to invoke the Apex classes to enable them to keep running at unequivocal circumstances, to start with, execute the Schedulable assemblage for the class, at that point express the calendar by using either the Schedule Apex page or the System.

10. What are the features of APEX?

Answer:

The different features of APEX are strong and strict data integration to perform the execution of multiple queries and statements concurrently, strongly typed which directly refers the object schema to provide the value, easy to use syntax which was derived from the java kind of programming language, easy testing which will provide easier execution and test suite creation.

11. What are the different data types in APEX?

Answer:

The different types of data types available in APEX language are Primitive Data Type (Integer, Long, Double, Date, DateTime, ID, or Boolean and String), Collections (Lists, Maps, and Sets) and Enum Classes, Interfaces and Objects. The Primitive data type Integer can be any value of a 32-bit number and will have some range similar to that of Java programming language. A Boolean data type will have a true and false value. The Date data type can only store the date value but not the time. The Primitive data type Long can be any value of a 64-bit number and will have some range similar to that of Java programming language. The String data type is a set of characters that will be initialized within single quotes. The data type Blob also exists which stores a binary set of data. Enum is an abstract kind of data type.

12. What is the distinction between apex:pageMessages, apex:pageMessage, apex: Message and apex: Messages?

Answer:

apex: PageMessages: This part shows all messages that were produced for all the components on the present page, introduced utilizing the salesforce styling. This will display both salesforce produced messages and also custom messages added to the ApexPages class.

apex: PageMessage: Apex: PageMessage is a segment that includes single message the page. This is utilized to show custom message utilizing the salesforce formatting.

apex: Message: apex: Message is utilized to show a mistake on just a particular field. It is utilized to enable developers to put handle particular mistakes in the particular area.

apex: Messages: apex: Messages is like apex: Message yet it shows all the errors.

13. How APEX Architecture works?

Answer:

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 oracle database. After the data is processed, results are relayed back to browser as HTML. This cycle happens each time user request or submit 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. Oracle HTTP Server: In this three-tier configuration, mod_plsql in Oracle HTTP Server acts a broker between client web browser and server database. For each URL that is processed, mod_plsql either uses a database session from its connection pool, or creates a new session on the fly and pools it. For mod_plsql to invoke the appropriate database PL/SQL procedure in a URL-processing session, you must first configure a virtual path and associate that path with a Database Access Descriptor (DAD). A DAD is a named set of configuration values that specify the information necessary to create a session for a specific database and a specific database user/password. This includes the database service name and the Globalization Support setting (for example, language) for the session. Embedded PL/SQL Gateway: This is a classic client-server architecture where embedded PL/SQL gateway provides the Oracle database with a Web server and also the necessary infrastructure to create dynamic applications. The embedded PL/SQL gateway runs in the XML DB HTTP server in the Oracle database and includes the core features of mod_plsql, but does not require the Oracle HTTP Server powered by Apache.

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

Answer:

There are several attachments that are part of the template form. APPSCORE: This is a kind of attachment that comprises of packages as well as procedures which 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 with the application code. There are various kinds of customization including zoom.

15. What is the difference between varchar and varchar2 data types?

Answer:

Varchar can store up to 2000 bytes and varchar2 can store up to 4000 bytes. While Varchar will occupy space for NULL value, Varchar2 will not occupy any space. They are differentiated by space.

16. What is Oracle Application Express?

Answer:

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. 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.

17. What are skills required for APEX Developers?

Answer:

SQL, PL/SQL are essential. HTML, CSS and JavaScript are good to have skills to understand and customize look and feel (themes, templates, ….

18. Are there any limitations in using Oracle XE?

Answer:

XE is free but Oracle has built certain limitations into the product. The first limitation is memory. Oracle Database XE can address only 1GB of RAM. This limitation mainly affects how many users can access the database concurrently and how well it performs. The second limit is that XE will only use one CPU. XE will run on a multi -CPU computer but wont scale up to use those CPUs. This functionality requires Oracle Database Standard Edition or Enterprise Edition. The third limit is that only a single XE database can run on any given computer. You do not need a database for each application. Instead, Oracle uses the concept of schemas to separate applications. Finally, a 4GB limit is enforced on disk space. 4GB is a huge amount of storage for most applications. You can also use APEX to link to other databases (on other servers) for more storage as needed.

19.Should static files be placed in the database?

Answer:

Application Express applications may reference additional external files such as cascading style sheets (CSS), images and Javascript libraries. These images can either be placed on the file system of the server that runs the web server or, when they are uploaded using Application Express’s application builder, can be stored inside the database. A benefit of managing files such as images and CSS in the database with the application builder is that they can be exported and imported into another Application Express environment or workspace using only a browser. However, storing related files in the database is recommended only when you have relatively few images and when the application is not expected to endure high request throughput. When images, CSS and Javascript libraries are stored in the database, a database connection is established each time the browser requests one of these files. In a high throughput application this may result in undue and unwanted strain on the database.

20. Which platforms are supported by Oracle Application Express?

Answer:

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

21. What are the applications of APEX?

Answer:

The different types of applications of APEX are to create different types of services such as email, schedules, triggering etc., creating different web services with integration of multiple systems and different services, performing validations on multiple schema objects and customized validation rules, creating customized business processes for the unavailable features.

22. What are the different Collections in APEX?

Answer:

The different collection data structures in APEX are Lists, Maps, and Sets. A List can have any type of data stored in it such as primitives, collections, different types of complex objects or schema objects. There will be different types of methods available in the lists to perform different operations such as to retrieve the size of the list, to clear the contents, to get the details of the list and to update, delete and add the records or values into it. The same functionalities do also exist for Set and Maps but with different functionalities.

23. What is Scheduler class in Apex? Is it conceivable to call the Apex method in javascript code? If yes then clarify?

Answer:

It is a class which is usually modified for running the pre-defined interim.The class must actualize schedulable interface and it contains technique named execute().Yes, we can call apex techniques utilizing javascript. We can accomplish this by using the ActionFunction.

24. How does APEX integrate with the database?

Answer:

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 link in additional libraries. On the rare occasions you need to extend functionality, you’ll either use SQL for data access or PL/SQL when procedural code is required.

25. What is WITH CHECK OPTION?

Answer:

The WITH CHECK option clause specifies the level of check to be done in DML statements. It aids in preventing changes to a view that would produce results not contained in the sub query.

26. What is hash cluster?

Answer:

Hash Cluster is a technique used for storing the table to make it faster to retrieve. It order to retrieve the rows from the table, apply the hash value on the table.

27. What is the utilization of interfaces?

Answer:

An interface takes after a class in which none of the strategies have been executed—the system marks are there, yet the body of each methodology is void. To use an interface, another class must realize it by giving a body to most of the procedures contained in the interface. Interfaces can give a layer of reflection to your code. They isolate specific execution of a system from the declaration for that procedure. In this manner, you can have unmistakable use of a methodology in perspective of your particular application.

28. What is APEX syntax?

Answer:

APEX syntax has different features such as variable declaration to store the different values in the memory. The queries will be like SOQL which will be used to execute the queries, loop statements to perform the iterations in performing the operations, flow control statements can be used to control the flow execution whether to start or stop the execution process, DML statements can be used to manipulate the data by executing the queries.

29. Tell me something about virtual class in the Apex programming?

Answer:

In a domain where you are leading protest situated sort of programming, a virtual class is a term alluded to a settled kind of internal class whose limit alongside the part factors can be effortlessly abrogated and furthermore renamed by alternate subclasses of some other outer class. Virtual classes are something that intently looks like the virtual limits of the program.

30. How is APEX Application components stored inside DB?

Answer:

This is first of a 3 part series on embedding files in your APEX application. 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 to 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. 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. Files that are added to the application aren’t stored on the web server. 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.

31. How do I separate development from production environment?

Answer:

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.

32. How much does APEX Cost and where can I get it?

Answer:

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.

33. What is the future of Application Express?

Answer:

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 non programmers 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.

34. How do I separate development from production environment?

Answer:

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.

35. What is Oracle Apex?

Answer:

Oracle Apex is a free web development tool. Apex runs on PL/SQL inside the web browser. Apex is a runtime environment. It is used to code web apps. User-specific with user ID lof into Apex & run the apps from the menu. We can create reports, forms & charts. Flexible to integrate our own javascript code. Outputs can be off the screen as PDF or to the screen, Flash, Excel Sheet or into web services via integration.

The most important and basic feature of Oracle Apex is that it is tightly integrated with Oracle DB, & fully capable of web development environment. We can even customize the theme or use the basic theme for look & feel of the application.

36. What is BLOB datatype?

Answer:

A BLOB data type is a binary string with a varying length which is used in storing two gigabytes memory. Length should be stated in Bytes for BLOB.

37. What are SET operators?

Answer:

The following are the advantages of APEX:

No license required it is free.
To build 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 are avoided.
Apex Framework & meta-data is stored in Oracle tables. It runs on live Oracle DB’s.

38. Define the support for APEX that exists?

Answer:

Application Express could be the best community for some to help deliver, develop & the use of APEX applications. The basic support is from APEX forum of Oracle Tech Network. We can find answers & tips related to development from in & out of Oracle.

39. What do you mean Apex?

Answer:

Apex is mainly in-house technology that is just like Java programming with object-oriented ideas and to compose our own particular custom logic.

Apex is the procedural scripting language in the discrete and executed by the Force.com stage.
It runs locally on the Salesforce servers, making it more ground-breaking and quicker than non-server code, for example, JavaScript/AJAX.
It utilizes the syntax that resembles Java.
Apex can be written in triggers that demonstration like database put away techniques.
Apex enables designers to join business logic to the record spare process.
It has worked in help for unit test creation and execution.

40. How will you direct your application to use https instead of http?

Answer:

create wallet from apache home (wallet should be in ready state)

configure ssl.conf file

restart apache

verify with opmnctl status.

41. What is RAW datatype?

Answer:

RAW data type is used in storing values in binary data format. The maximum size of a RAW in a table is 32767 bytes.

42. What is NULL value in Oracle?

Answer:

NULL value represents unknown or missing data. It is used as a place holder or represented as a default entry indicating that no actual data is present.

43. What is an ALERT?

Answer:

An alert is a window which appears in the center of the screen and overlays a portion of the current play.

44. What is a view?

Answer:

View is a logical table that is based on one or more tables and views. The tables which the view is based upon are called Base Tables and it contains no data.

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

Answer:

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

46. What is the use of NVL function?

Answer:

The NVL function is used for replacing NULL values with given or another value. E.g. NVL(Value, replace value)

47. What is the fastest query method to fetch data from the table?

Answer:

You can use ROWID to fetch Row from the table. The use of ROW ID is the fastest query method for fetching data from the table.

48. What is the distinction amongst public and Global class in Apex?

Answer:

The Public access modifier is not quite the same as people in general modifier in Java. The public class can be accessed inside an application or namespace. While the Global class is mainly noticeable wherever: in any of the application or the namespace. The Webservice must be proclaimed as Global so it can be accessed outside of the application. The global variable is like open modifier in Java.

49. SQL Statement that defines a foreign key constraint on column DEPT NO1 of EMP1 Table?

Answer:

CREATE TABLE EMP1 (empno NUMBER(301), ename VARCHAR(45), deptno NUMBER(5,3), NOT NULL, CONSTRAINT emp1_deptno1_fk FOREIGN KEY deptno1 REFERENCES dept1(deptno1));

50. What are the different type of apex users?

Answer:

Users are divided into three primary roles developer, Workspace administrators and Instance administrators.