Top PostgreSQL Interview Questions (2021) | CodeUsingJava
















Most frequently Asked PostgreSQL Interview Questions


  1. What is PostgreSQL?
  2. What are the Features of PostgreSQL?
  3. What are the Datatypes used in PostgreSQL?
  4. Explain PostgreSQL Architecture?
  5. What are the Features of PostgreSQL?
  6. What is Multi-version control?
  7. How is pgadmin used in PostgreSQL?
  8. What is a Parallel Query?
  9. What are the Languages supported by PostgreSQL?
  10. How to create database in PostgreSQL?
  11. What is PostgreSQL role?
  12. What is command enable-debug?
  13. What are the Database Administration Tools supported by PostgreSQL?
  14. What is the purpose of Array_To_String in PostgreSQL?
  15. How can we show tables in PostgreSQL?
  16. How do we change PostgreSQL user password?
  17. How can we create a copy of a database in PostgreSQL?

What is PostgreSQL?

PostgreSQL is used for Object-Relational Database Management System which is used in large Web Applications.PostgreSQL is an open-source that helps in providing substantial and additional power by incorporating basic concepts like extending the system without any problem. It is also used for extending and using SQL Language which is combined with features such as Safety Scale and Storing Intricate Data Workloads.

What are the Features of PostgreSQL?

PostgreSQL

What are the Datatypes used in PostgreSQL?

Different types of Datatypes are as follows:
UUID
Numeric Types
Boolean
Character Types
Temporal Types
Geometric Primitives
XML
Arrays

Explain PostgreSQL Architecture?

PostgreSQL
PostgreSQL is fully based on Client Server architecture.It consists of PostgreSQL's Background processes and sharing memory for building instance.The instance can handles accessing data, user can connect application to this instance and also requests the services for writing, reading the Operations to the Database Server.

What are the Features of PostgreSQL?

  • Language Support - PostgreSQL uses languages such as PL/pgSQL, PL/Tcl, PL/Perl and PL/Python.
  • Indexes - PostgreSQL can create the users customized indexes.
  • Views - PostgreSQL also supports creating virtual tables.
  • Rules - PostgreSQL helps in allowing hierarchy of incoming query.

What is Multi-version control?

MVCC(Multi-Version Concurrency Control) helps in avoiding unnecessary locking of the database. It also helps in removing the time lag for the user for logging into the database. It occurs when someone is accessing the content and the transactions can be kept as a record.

How is pgadmin used in PostgreSQL?

pgadmin is a feature used for forming a front-end Graphic Administration Tool, it is also available as software with an Artistic License. The database administration tool that can be available with an Artistic License is Pgadmin iii. It is also used for retrieving information, developing, testing, and continuous maintenance of Databases.

What is a Parallel Query?

Parallel Query is a feature of PostgreSQL which helps in designing Query Plans which can also leverage some CPUs for responding easily and quickly to Queries.

What are the Languages supported by PostgreSQL?

PostgreSQL

How to create database in PostgreSQL?

We can create database by using the following command:
CREATE DATABASE dbname;


What is PostgreSQL role?

The role is PostgreSQL cluster entity that is used for grouping database permissions, it is also a group of privileges that can be granted to many other databases or role users.

What is command enable-debug?

Command Enable-Debug is used for enabling the compilation for all the libraries and applications. It helps in executing the procedure that impedes the system and can also amplify the Binary File Size.
Debugging Symbols are used for representing assist developers in spotting bugs and problems that can arise with the scripts.

What are the Database Administration Tools supported by PostgreSQL?

Database Administration Tools supported by PostgreSQL are as follows:
  • Psql
  • Pgadmin
  • Phppgadmin

What is the purpose of Array_To_String in PostgreSQL?

The function can concatenates array elements using a delimiter such as:
SELECT array_to_string(ARRAY[2, 3, 4, NULL, 5];


How can we show tables in PostgreSQL?

We can show tables by using the following command line:
SELECT * FROM pg_catalog.pg_tables;


How do we change PostgreSQL user password?

We can change PostgreSQL user password by using the following command:
ALTER USER user_name WITH PASSWORD 'new_password';


How can we create a copy of a database in PostgreSQL?

We can create a copy of database by using the following command:
create DATABASE newdb by TEMPLATE originaldb OWNER dbuser;