Top 20 PostgreSQL Interview Questions with Answers

Hello guys, if you are preparing for Postgres Interview or a Java development role where PostgreSQL skills are needed but not sure how to prepare, what to prepare etc and looking for PostgreSQL Interview questions with answers then you have come to the right place. Earlier, I have shared 50 SQL Phone interview questions and 6 SQL Query questions and in this article, I am going to share frequently asked PostgreSQL questions with answers. You can use these questions and answers to prepare well for your Job interview and you can also learn essential PostgreSQL concepts by going through these questions.

Preparing well for an interview is one of the best things you can do when seeking a job. Good preparation boosts your confidence and this will really count when the actual interview takes place. Getting to know the questions that are frequently asked in a particular interview is among the ways of preparing. 

You will be one step ahead of the other candidates if you brace yourself with answers to the vital questions that cannot fail to be asked in an interview In this article, I have highlighted top 20 PostgreSQL interview questions with answers that you must surely have a look at.

I have you in mind and that is why you are here reading this article. Please do not rush but just take your time so that you do not miss any important question.




20 PostgreSQL Interview Questions with Answers

Now, let's dive into 20 frequently asked PostgreSQL interview questions and their answers. You can use this list to quickly revise the essential concepts before you go for any interview where PostgreSQL skills are required.

The questions are up to date and this means that whatever knowledge you will gather from the answers of these questions, will be useful to you as far as PostgreSQL interview is concerned. All you need to do is to have a pen and paper and also be focused.


1. What is PostgreSQL?
Answer: It is a general purposed and advance object-relational database management system.

2. What is PostgreSQL used for?
Answer: It is mainly used for adding custom functions developed using various programming languages such as Java, C and C++.

3. What are the features of PostgreSQL?

Answer: PostgreSQL has quite a number of features. Just a few of them are as follows;

  • Easy compatibility with other languages and important platforms.
  • Supports multi-version concurrency control.
  • High availability and standby server.
  • Supports client-server network architecture.


4. What is the maximum size for a database in PostgreSQL?
Answer: There is no specific maximum size for a database in PostgreSQL. This means that users can be able to put or store unlimited amount of data in it. This is good news for users with large volumes of data. The only thing that is limited is the size of the table, row and field.

5. What is base directory in PostgreSQL?
Answer: Base directory in PostgreSQL is simply the folder in which PostgreSQL stores all the data that you have inserted in your databases. The base directory contains sub directories which are used in your clusters by a database. 

Top 20 PostgreSQL Interview Questions With Answers



6. What is the procedure of installing PostgreSQL on windows?
Answer: Installing PostgreSQL on windows is something that you can do with ease. You just have to follow the following procedure;

  • First download Windows PostgreSQL, click once the installer and run it.
  • Select to install PostgreSQL as a Windows Service.
  • If requested, change the installation directory and proceed to next.
  • Select the components you would like to install.
  • If requested, also change the data location.
  • Enter the user password.
  • After the installation is complete, uncheck the Stack Builder prompt and then click finish.
  • Go to the start menu then search and start pgAdmin 4.
  • Select PostgreSQL 10 from the servers available on the pgAdmin homepage.
  • Finally key in the super user password and the dashboard will be set for use.

7. What does indexes mean in PostgreSQL?

Answer: in simple terms, as used in PostgreSQL, the index is a common way for database performance enhancement.

8. What are the data types found in PostgreSQL?
Answer: There are several data types in PostgreSQL namely;
  • Character types
  • JSON
  • Array
  • Numeric types
  • Store
  • Boolean
  • Temporal types
  • UUID

9. Name the types of indexes supported in PostgreSQL?

Answer: PostgreSQL has a couple of index types which are B-tree, Hash, SP-GIST, GIN and BRIN.

10. Define tokens as used in PostgreSQL?

Answer: When it comes to PostgreSQL, a token is simply a keyword.

11. How can one change a user’s password in PostgreSQL?

Answer: Changing a password in PostgreSQL involves three steps. They are as follows;
  • First you have to ensure you make yourself a “postgres” system user. This can be done through the root user.
  • Then second, you have to connect to the local server. You will use “PSQL” to connect.
  • Lastly, type the meta command of PSQL or password.

12. What is the meaning of sequence in PostgreSQL?

Answer: In PostgreSQL, a sequence can be defined as a form of data which is special and is mainly created in order to generate multiple numeric identifiers in the PostgreSQL database.

13. Define string constants as used in PostgreSQL?

Answer: In PostgreSQL, a string constant is defined as an arbitrary sequence of multiple characters which are bounded by single quotes.

14. What is inverted file in PostgreSQL?
Answer: An inverted file is simply an index data structure that is usually used when mapping content to its location to a database file in a document or even in a set of documents.

15. Define a partitioned table as used in PostgreSQL?
Answer: A partitioned table is a structure that is logical in nature and it is used to split a large table into smaller pieces or sections.

16. How do you delete the database in PostgreSQL?
Answer: Deleting database in PostgreSQL can be done using any of the following two options;
  • Using dropdb – a command-line executable.
  • Using DROP DATABASE – an SQL command.

17. What are the advantages of PostgreSQL?

Answer: PostgreSQL has a number of advantages. The following are the advantages;
  • Diverse indexing techniques
  • Open source DBMS
  • Full-text search
  • ACID Compliance

18. How to start PostgreSQL on windows?

Answer: It is easy to start PostgreSQL IN windows and it only requires you to perform four quick steps as follows;
  • Open Run Window by Windows + R.
  • Type services. msc.
  • Search for Postgres service. This will depend on the version that you have installed.
  • Finally, you will click start the service option.

19. How to stop PostgreSQL on windows?

Answer: Stopping PostgreSQL in windows involves four simple steps. The following are the steps;
  • Open Run Window by Windows + R.
  • Type services. msc.
  • Search for Postgres service. This will depend on the version that you have installed.
  • Then lastly, you will click stop the service option.


20. What is the latest version of PostgreSQL?

Answer: The latest version of PostgreSQL is 12.3 and it is the best since it has more advanced features as compared to the other previous versions.


That's all about the frequently asked PostgreSQL interview questions with answers for 1 to 2 years experienced programmers and DBAs. You can use these questions to not only prepare well but also learn essential PostgreSQL concepts.

In conclusion, all you have to do is to focus on the above mentioned questions and you will have it easy during your interview. These are just simple questions with straight forward answers so you do not need to worry any more. 

Remember adequate preparation is what might save you during your interview. Having all these answers with questions at your finger tips is the real meaning of adequate preparation so to say. I therefore take this opportunity to wish you nothing but success in your interview.


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