Top Oracle Interview Questions & Answers
Technology advances at a breakneck speed. It is especially true in computer science and telecommunications, where new software and its applications are frequently updated. It means that as an IT expert, you must always stay alert. In this field, businesses are continuously looking for programmers who are up to date on the latest advances.
You can ace any interview, regardless of your experience in the industry (novice or expert). Here are some of the Oracle interview questions, along with their answers.
- What is Oracle’s function? What’s more, how does it work?
Oracle Database, sometimes known as Oracle, is a relational database management system (RDBMS). It’s a piece of software that processes, stores, retrieves, and manipulates data. It is based on PQ/SQL, a SQL extension (Structured Query Language).
Oracle analyses, manages and retrieves data using memory threads within the main memory system.
- What are the many methods you can use to write comments in Oracle?
You can use two dashes (–) for single statements.
You can use (*–*) for a block statement.
- What are constraints, and how may they be used to our advantage?
Constraints are data-related rules that you create.
They can use them to create a table or modify one already created.
- What is the difference between a Primary key and a Unique key?
A primary key is used for identifying a specific record in a data database. Only one primary keyword is presented in the table, and it cannot have a null value.
On the other hand, unique keys are employed to prevent value duplication in the system. A table can have several Unique keys, each with a null value.
- What is the difference between TRANSLATE and REPLACE?
When you want to replace characters one by one, TRANSLATE is the way to go, but REPLACE allows you to replace an entire string with a new one.
- What is the difference between COALESCE and AGGREGATE?
The COALESCE command returns a table value that is not null.
The AGGREGATE command combines many records’ values into a single value. For example, sum, average, and count are functions.
- How well do you understand Oracle’s set operations?
They are commands for combining inquiries to produce unique results.
INTERSECT, for example, will return the results that are common to all of the queries that have been run. You can use MINUS to get a return solely relevant to the initial query.
- What is the best way to establish a database trigger?
It can establish an APL/SQL block with the CREATE TRIGGER clause that will automatically activate when its conditions are met.
- What are Savepoints used for?
Savepoints are markers set up during programming, much like a video game. We can go back to the savepoint if a particular transaction fails.
- What exactly are errors, and how do you handle them?
Exceptions arise during programming and are typically handled with the EXCEPTION block command.
- What are privileges, and what are they used for?
Access to another user’s data or the ability to execute a command is granted by privileges. They’re used to create roles, and any user can enable or disable them.
- What is the distinction between Alias and Rename?
Alias is a temporary name, whereas Rename is a permanent name assigned to a record.
- What is a point of view?
It’s a logical table with no data based on one or more other tables.
- What are the advantages and disadvantages of Integrity Constraints?
These commands ensure that data in the system is accurate and consistent. There are several sorts of integrity, including Domain Integrity and Referential Integrity.
- What is the difference between DECODE and CASE statements?
Both commands transform data values and can be used in conjunction.
- What is the best way to combine two tables?
Using the MERGE command, you can integrate data from multiple tables. Based on the query provided, it selects and updates data in the source table and the second table accordingly.
- What is a Stored Procedure?
They are a collection of commands written to accomplish a particular purpose and saved and identified as a group.
- What is the Index’s function?
It is used to search for data within a database efficiently.
- What is a Data Dictionary, exactly?
It’s a collection of read-only tables that store metadata about a user’s information.
- What do you mean by “joins”?
They are commands used for getting information from many tables with a similar column.
Preparing for an Oracle Interview
Now that we have learned about the Oracle interview questions, here are some pointers on how to ace your Oracle interview and land a job:-
Have a decent understanding of Java – The Java programming language is one of Oracle’s most popular products, so it’s good to brush up on your Java knowledge before the Oracle coding interview. Also, understanding Java frameworks such as Spring and the SOLID principles of Object-Oriented Design can be quite beneficial.
Be well-versed in Data Structures and Algorithms – Good problem solvers are usually appreciated at Oracle. If you plan to make a good impression on the interviewers, let them know about your effort to create your logic structures and solve algorithmic challenges. A solid understanding of algorithms and data structures and one or two successful projects will always gain you brownie points while answering the oracle interview questions.
Discuss with your interviewer and keep the conversation moving – Keep in mind that an interview is not a written exam, so even if you have the most satisfactory solution for the provided difficulties, it will be useless until the interviewer understands what you’re attempting to communicate. As a result, it’s critical to convince the interviewer that they are also a participant in the conversation. In addition, asking questions during the interview may always be beneficial.
In addition to having a good grip on your subject, make it a point to pay close attention to the interviewer. Even the most straightforward oracle interview questions can appear complex if you don’t understand them.