Oracle Developer Interview Questions

Responsibilities

Oracle developer responsibilities may include:

• Designing applications for the Oracle platform
• Working with other software engineers in team environments
• Preparing workflow charts
• Correcting errors in programs
• Automating processes within the application

Skills

Oracle is the most popular system in the world for running online transaction processing. In order to deliver a positive user experience, skilled Oracle evelopers will:

• Possess capabilities in data analysis
• Communicate effectively with team members
• Possess an eye for detail in order to identify broken code
• Provide troubleshooting services as needed
• Communicate relevant timelines and milestones to employers

Qualifications

A bachelor’s degree in computer science or a similar field is required for entry-level jobs. In addition, candidates must complete an Oracle certification in order to work on the Oracle platform professionally.

Salary

Salaries for Oracle developers range between $72K and $112K with the median being $94K. 

Factors impacting the salary you receive as an Oracle developer include:

• Degrees (associate's or equivalent technical training, bachelor's, master's)
• Years of Experience
• Location
• Reporting Structure (seniority of the manager you report to and number of direct reports)
• Level of Performance - exceeding expectations

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Oracle Developer Interview Questions

Question: Can you provide an overview of Oracle?

Explanation: This is a typical opening or general question used by the interviewer to begin the interview, learn a little bit more about your background, and collect some information they can use for other questions they will be asking.

Example: “Oracle is one of the more popular databases and was developed by the Oracle Corporation. It is the foundation for other applications developed by both Oracle and third parties. Since it uses relational management concepts, it is referred to as a relational database management system or RDBMS. Some of its applications include online transaction processing, data warehousing, and enterprise computing.”

Question: What is the nomenclature used to identify Oracle database software releases?

Explanation: This is a technical question. As an Oracle developer, you can anticipate that the majority of the interview will involve technical and operational questions. These are best responded to briefly and directly with little embellishment. The interviewer will ask a follow-up question if they need additional information.

Example: “Oracle has a specific nomenclature which they use for each release of the Oracle database software. This helps developers as well as users identify which version of the software they are working with. A typical format is release 10.1.0.1.1. Each of these numbers has a specific meaning which are:

• 10: major DB release number

• 1: DB maintenance release number

• 0: application server release number

• 1: component-specific release number

• 1: platform-specific release number”

Question: What process is used to create privileges in Oracle?

Explanation: This is an operational question. Much like technical questions, operational questions explore your knowledge and skills within the Oracle developer profession. Operational questions seek to understand how you go about doing your job.

Example: “Privileges within Oracle are the right to execute queries as well as access other objects within the database. The two classes of privileges include user system privilege. The system privilege provides greater access to the database and the ability to do more. Privileges are assigned using the following command string:

[sql]GRANT user1 TO user2 WITH MANAGER OPTION;[/sql]”

Question: Can you define the term VArray as it is used within Oracle and discuss how it is used?

Explanation: This technical question asks you to define a term and then discuss how it is used in the position for which you are interviewing. This is the typical structure of a technical question. Remember to keep your answer short and to the point. The interviewer will ask a follow-up question if they need additional information.

Example: “VArray is a data type used by Oracle to enable columns to contain multivalued attributes. It can also hold a bounded array of values.”

Question:  What command is used to obtain the details of the fields in a table?

Explanation: This question asks for a specific command to accomplish the task defined in the question. You answer this question by stating that command and then describing what it does.

Example: “The command used to get the details of fields of a specified table is describe.”

Question: Can you discuss the differences between the rename and alias commands in Oracle?

Explanation: This question asks you to compare two similar but different commands within Oracle. The best way to answer this question is to define each term and then describe what they do or what the differences between them are.

Example: “Both rename and alias are commands used to name a table or column within Oracle. The difference between these is that rename provides a permanent name for these items replacing the existing one while alias provides an alternate name for the table or column while preserving the original one.”

Question: How do you differentiate between VARCHAR and VARCHAR2?

Explanation: Here is another technical question asking you to define the differences between two similar terms. Again, start your answer by defining the terms and what they do and follow with a brief description of the differences between them.

Example: “Both VARCHAR and VARCHAR2 are Oracle data types used to store character strings of variable length. One difference between them is VARCHAR2 can store twice the number of bytes as VARCHAR, 4000 vs. 2000. Also, VARCHAR will reserve a space for characters defined during declaration, even if they are not used, whereas VARCHAR2 will release any unused space.”

Question:  What are the differences between Oracle’s TRUNCATE and DELETE commands?

Explanation: This is another technical question asking you to distinguish between two different commands within Oracle. As the interview progresses, the questions will become more specific and more difficult. This indicates the interviewer is gaining confidence in your abilities and is willing to explore more complex topics. Continue to answer these questions just as you did the easier ones.

Example: “Both the TRUNCATE and DELETE are commands used to delete data from the database. The differences between these two similar commands are:

The TRUNCATE command will drop the structure of a database and can’t be rolled back while the DELETE command can be.

DELETE is a DML operation, and TRUNCATE is a DDL operation.

TRUNCATE frees the object’s storage space, but DELETE does not.”

Question:  Can you describe what a RAW datatype is and how it is used?

Explanation: This is a classic technical question asking you first to define a term and then describe how it is used. As mentioned before, technical questions should be answered briefly and directly. You should anticipate a follow-up question any time you respond to a technical question. This will indicate  the interviewer either needs more information or has a specific interest in this topic.

Example: “A RAW datatype is used to store variable-length binary data or byte strings. Since SQL doesn’t recognize this data type, it cannot do a conversion when RAW data is transferred to a different system. Also, RAW data types can only be queried or inserted in a table.”

Question:  Can you define the term joins as it is used in Oracle and list some of the types of joins?

Explanation: The interviewer is continuing to ask you technical questions. The best way to prepare for an interview as an Oracle developer is first to review the job posting, noting the requirements for the position. You should then research the company, its products, and the software it develops. This will give you an idea of the type of methodologies, commands, processes, and procedures they use. Once you know these, refresh yourself on typical Oracle terms, development methodologies, and commands.

Example: “Within Oracle, joins are used to extract data from multiple tables using common columns or conditions. The different types of joins include inner, outer, cross, equi, anti, and semi.”

Additional Oracle Developer Interview Questions

• What methodologies have you used in previous work experience?

• What tools would you use to tune your SQL?

• Do you know how to find duplicate records in a database table?

• Can you explain your day-to-day duties as a developer? 

• What does the PL/SQL optimizer do?