Commonly Asked Oracle Interview Questions for a Successful Job Application - IQCode

Oracle Interview Questions

Below are 4 Oracle interview questions:

  1. What is the difference between a clustered and a non-clustered index?
  2. What is a cursor in Oracle?
  3. What is the difference between a unique and a primary key constraint?
  4. What is the difference between a left join and an inner join?

About Oracle

Oracle, one of the largest multinational computer technology corporations in America, is headquartered in Austin, Texas. The company specializes in selling cloud engineered systems, database software and technology, and enterprise software products, with a particular emphasis on their own brands of database management systems. As the second-largest software company in terms of revenue and market capitalization, Oracle is well-known for developing and building tools for database development and systems of middle-tier software.

Additionally, the company offers Human Capital Management (HCM) software, enterprise resource planning (ERP) software, customer relationship management (CRM) software, supply chain management (SCM) software, and enterprise performance management (EPM) software.

Oracle's outstanding work culture and principles, along with its high-quality products, have contributed to its increasing popularity in the IT industry. As a software developer, it is essential to maintain a good work-life balance, and Oracle is well known for providing this. To learn more about software career opportunities available at Oracle, visit their website.

Oracle Interview Process, Coding Questions, and Technical Interview Tips

// Oracle Interview Process // The Oracle Interview Process typically involves a phone screen, followed by multiple rounds of on-site interviews with technical, managerial, and sometimes HR personnel.

// Oracle Coding Question // A common coding question asked during an Oracle interview is to write a program that checks if a given string is a palindrome. Here's an example solution in Java:

public boolean isPalindrome(String str) { str = str.replaceAll("[^a-zA-Z0-9]", "").toLowerCase(); return str.equals(new StringBuilder(str).reverse().toString()); }

// Oracle Technical Interview Questions // Oracle Technical Interview Questions can cover a range of topics, including database management, Java programming, and cloud computing. Here are a few example questions: // 1. How do you optimize a SQL query? // 2. Can you explain the difference between an abstract class and an interface in Java? // 3. What is your experience with Oracle Cloud Infrastructure?

// Tips for interviewing at Oracle // Some tips for successfully interviewing at Oracle include preparing for technical questions, researching the company culture and values, and demonstrating strong communication and problem-solving skills.

// FAQ for Oracle // Commonly asked questions about Oracle include inquiries about its cloud offerings, database management solutions, and enterprise software products.

Oracle Interview Process



If you're considering working at Oracle, you may be interested in learning about the company's interview process. Oracle deeply values its teams and hiring highly skilled people from diverse backgrounds is an essential part of building a representative and inclusive workforce. The hiring team believes that a fair hiring process is critical to achieving their goal. To help you understand what the interview process at Oracle entails, here is an overview of the steps involved:

Interview Rounds

* Online Coding Round: This round involves an online test that includes multiple-choice questions covering topics such as logical reasoning, quantitative analysis, data structures and algorithms, networking, object-oriented programming, and database management systems. * Technical Interview Round 1: In this round, a video or phone call is scheduled with the candidate to assess their coding skills. The interviewer typically asks two questions related to data structures and algorithms. * Technical Interview Round 2: The second technical interview is conducted in person and focuses on asking complex and tricky questions about data structures and may also cover topics related to the candidate's CV. Some interviewers may also ask puzzles to test the candidate's thinking ability. * HR Round: This is an informal interview in which the interviewer can ask general questions about the candidate's work experience, ethics, and determine cultural fit with the company.

Oracle's hiring process is an essential part of their company culture, and they take it very seriously. They aim to ensure that everyone has an equal opportunity and that diverse perspectives and experiences are welcomed in their company. If you're passionate about technology and want to work at a company that values their employees, Oracle may be the right fit for you.

Oracle Coding Questions

Below are some coding problems that you can solve:

//given a matrix, if an element is 0, set its entire row and column to 0

public void setZeroes(int[][] matrix) {
    if(matrix == null || matrix.length == 0) {
    int m = matrix.length;
    int n = matrix[0].length;
    boolean[] row = new boolean[m];
    boolean[] col = new boolean[n];
    // Check which row and column contains 0
    for(int i = 0; i < m; i++) {
        for(int j = 0; j < n; j++) {
            if(matrix[i][j] == 0) {
                row[i] = true;
                col[j] = true;
    // Set entire row and column to 0 if the corresponding row or column contains 0
    for(int i = 0; i < m; i++) {
        for(int j = 0; j < n; j++) {
            if(row[i] || col[j]) {
                matrix[i][j] = 0;
//Given a binary tree, find its maximum depth

public int maxDepth(TreeNode root) {
    if(root == null) {
        return 0;
    int leftDepth = maxDepth(root.left);
    int rightDepth = maxDepth(root.right);
    return Math.max(leftDepth, rightDepth) + 1;
//Given a Binary Tree, find its diameter

public int diameterOfBinaryTree(TreeNode root) {
    if(root == null) {
        return 0;
    int leftHeight = height(root.left);
    int rightHeight = height(root.right);
    int leftDiameter = diameterOfBinaryTree(root.left);
    int rightDiameter = diameterOfBinaryTree(root.right);
    return Math.max(leftHeight + rightHeight, Math.max(leftDiameter, rightDiameter));

private int height(TreeNode node) {
    if(node == null) {
        return 0;
    return Math.max(height(node.left), height(node.right)) + 1;

Oracle Technical Interview Questions

Physical Database Structure of Oracle ---------------------------------------

What are the various components of the physical database structure of an Oracle database?

There are three main components of the physical database structure in an Oracle database:

- Two or more redo log files - One or more data files - One or more control files

Oracle Database Development ---------------------------

What language was used to develop the Oracle database?

The Oracle database was developed using the C language.

Logical Database Structure of Oracle ------------------------------------

What are the main components of the logical database structure in Oracle?

The logical units of database space allocation are data blocks, extents, segments, and tablespaces. At the physical level, the data is stored in data files on a disk. The data in the data files are stored in operating system blocks.

The two main components of the logical database structure in Oracle are: - Tablespaces: The basic storage allocation in an Oracle database is a tablespace. The SYSTEM tablespace is used to create each and every database. Other tablespaces may also be created by the Database Administrator. - Database's schema objects: A schema in Oracle is similar to an account or a username. Each object in the database is owned by a schema. Two initial schemas that are created with every Oracle database are SYS and SYSTEM. Other schemas may also be created by the DBA.

What is a tablespace in the context of the Oracle database?

The logical storage unit of an Oracle database is called a tablespace. Tablespace groups relate the logical structures of the database together.

List the default tablespaces of Oracle.

The default tablespaces of Oracle include: - SYSTEM and SYSAUX tablespaces: They store system-generated objects such as data dictionary tables in them. No other objects should be stored in these tablespaces. - USERS tablespace: It is used for ad-hoc users. - UNDOTBS1 tablespace: Used for holding the undo data. - TEMP tablespace: It is a temporary tablespace that is used for storing intermediate results of sorting, hashing, and large object processing operations.

What is the difference between an online and an offline tablespace?

If a tablespace is offline, data stored in it cannot be accessed. If a tablespace is online, its data is both available for reading and writing.

SYSTEM Tablespace in Oracle ----------------------------

Explain the SYSTEM tablespace. When is it created?

When a database is created in the Oracle database system, a SYSTEM tablespace is automatically generated. The data dictionary tables of the entire database are present in this SYSTEM tablespace. It is important that the SYSTEM tablespace remains online at all times, as it contains the data dictionary that must be available to Oracle.

Oracle Table -------------

What is an Oracle table?

An Oracle table is a basic unit of data storage in an Oracle database. All accessible information of any user is present in rows and columns of an Oracle table.

Oracle Snapshot ---------------

What is a snapshot in the context of an Oracle database?

Oracle uses snapshots, also known as materialized views, to replicate data to non-master sites in a replicated environment. Snapshots may also be used to cache the "expensive" queries in a data warehouse environment. A snapshot is a copy of the target master table from a single point in time.

RAW Datatype in Oracle -----------------------

What do you understand about the RAW datatype?

The RAW datatype is used to store values in binary data format in an Oracle Database. A RAW datatype in a table can have a maximum size of 32767 bytes.

Memory Layers in Oracle Shared Pool -----------------------------------

What do you understand about the memory layers in the Oracle shared pool?

There are two memory layers in the Oracle shared pool: - Library Cache: Contains information about the SQL statements that were parsed, data about cursors, and any plan data that might be present. - Data Dictionary Cache: Contains information about the accounts of the users, their privileges, and information about segments.

Savepoint in Oracle --------------------

Tips for Oracle Interview Preparation


If you are preparing for an interview with Oracle, here are some tips to help you have a successful interview and potentially land your desired job:

- Develop a good understanding of Java: Java programming language is one of the most commonly used products at Oracle, so having an in-depth knowledge of Java and its frameworks, such as Spring, along with mastery of Object-Oriented Design and the SOLID principles can be very helpful for your coding interview.

- Be well-versed with data structure and algorithms: Problem-solving skills are always highly appreciated at Oracle, and a good knowledge of data structures and algorithms with demonstrated proficiency in projects can earn you high scores from your interviewers.

- Use the STAR method to structure your response: Responding to behavioral based interview questions with the STAR acronym (Situation, Task, Action, and Result) is a structured way to showcase how you responded to various real-life situations using problem-solving skills, and what results were achieved. Recalling details and involving others is crucial and powerful in showcasing your potential.

- Describe your strengths: Many interviewees feel uncomfortable with describing their strengths, but it is crucial to showcase your skills properly and honestly in order to stand out.

- Keep the conversation going with the interviewer: Your interview is not just merely an exam, but a conversation in which you should look to leave a positive impression with the interviewer. You can do this by making the interviewer part of the interview and asking them questions. It shows that you are enthusiastic and serious about getting the job.

Frequently Asked Questions about Oracle

Here are some common questions about Oracle and their answers:

  • How many rounds are conducted in an Oracle interview for a Software Engineer?
    3-4 rounds are usually conducted which include Online Coding Round (1 round), Technical Round (2 rounds), and HR Round.
  • Why do you want to join Oracle?
    I want to join Oracle because of the high-quality products that Oracle works on every day. There are many opportunities presented to Oracle employees, and the company's work culture is excellent. Additionally, the compensation offered to Oracle employees is on the higher end of the standards of the Information Technology or Software Industry.
  • Are Oracle interviews hard?
    The toughness of the interview depends on the amount of hard work you put in to prepare for it. Usually, the questions asked in a standard Oracle interview are easy to medium difficulty level, but it varies from person to person. Since the number of interview rounds can range anywhere from four to seven, it can be intimidating at times, but if you are in, it will be worth the effort.
  • What are some questions that one should ask the interviewer at Oracle?
    It is always nice to ask questions about the company’s culture, what is the current technology being used to make the products, future innovations at Oracle, and the interviewer's personal experience at Oracle. Additionally, asking what skills you must develop before joining the job may prove useful.
  • What are some famous products of Oracle?
    Some of the famous products of Oracle are Oracle Database, Oracle E-Business Suite, PeopleSoft Enterprise, Siebel, and Oracle JDeveloper, a freeware IDE.
  • What are the skills required for an Oracle developer?
    Having a good knowledge of Java will prove helpful to an Oracle developer. Additionally, having a thorough knowledge of SQL databases, cloud technologies, and various models of software engineering, such as Agile Method, Waterfall Method, etc. might prove to be useful.
  • How do I get hired at Oracle?
    Oracle looks for people with extremely good problem-solving skills, preferably those who are well-versed with Data Structures and Algorithms and can apply them in real-world problems. Having a few good projects, preferably using Java and its frameworks like Spring, etc., may also increase the chance of getting hired at Oracle.

Technical Interview Guides

Here are guides for technical interviews, categorized from introductory to advanced levels.

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Best MCQ

As part of their written examination, numerous tech companies necessitate candidates to complete multiple-choice questions (MCQs) assessing their technical aptitude.

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