PostgreSQL Interview Questions and Answers
We are going to discuss the most interviewer asked PostgreSQL interview questions for the acknowledgment of future aspirants in this niche. PostgreSQL is one of the most advanced, object-relational database management systems and open-source developed by PostgreSQL Global Development Group at Berkeley Computer Science Department, University of California. With its strong hand on proven data integrity, reliability, architecture, extensibility, and excellent feature set, PostgreSQL has earned the prominence of being a superior and robust solution globally, thus highly increasing the employment base for this niche.
With the operation freedom of all major operating systems including UNIX, Windows, Linux, and Mac OS X; PostgreSQL supports images, text, video as well as sound, and includes programming interfaces for C, C++, Perl, Java, Tcl, Ruby, and Open Database Connectivity.
| Quick Questions about PostgreSQL | |
|---|---|
| What is the Latest Version of PostgreSQL? | 13.1 released on 12 November 2020 |
| When was PostgreSQL Initial released? | 8th July 1996 |
| What language does PostgreSQL use? | C Language |
| Who developed PostgreSQL? | Michael Stonebraker |
| What operating system use PostgreSQL? | Windows, Linux, macOS, OpenBSD |
Now, let’s discuss an advanced set of PostgreSQL interview questions further above for candidates searching for a near-future job change or going to start their career from the ground level.
Most Frequently Asked PostgreSQL Interview Questions
Multi-Version Concurrency Control (MVCC) is an advanced method used in PostgreSQL for improving the performance of a database in a multi-user environment. Unlike lock models in other databases, PostgreSQL uses a multi-version environment in which locks that are acquired for reading data don’t conflict with locks acquired for writing the data. Hence, making the process more compartmentalized and a lot faster.
| S.no | PostgreSQL | MongoDB |
|---|---|---|
| 1. | It’s an object-relational database management system. | It uses JSON-like documents to store schema-free data. |
| 2. | uses tables, triggers, constraints, roles, stored procedures and views as the core components | Uses Key, Collection, Document, and Value. |
| S.no | Oracle | PostgreSQL |
|---|---|---|
| 1. | Mostly aid object-relational database management system | open source object-relational database management system |
| 2. | The implementation language is C. | Implementation language is C and C++. |
| 3. | Server operating systems here are OS X, Linux, Windows, z/OS, AIX, and HP-UX. | Server operating systems here are HP-UX, NetBSD, Solaris, Windows, Unix, Linux, and FreeBSD. |
| 4. | More database productivity | Less database productivity |
| 5. | Advance security options | Good security support but less compared to Oracle |
- Download Windows PostgreSQL one-click the installer and run it.
- Choose to install PostgreSQL as a Windows Service.
- If needed, change the installation directory and click next
- Choose the components you want to install & click next
- If needed, change the data location
- Enter the user password and if necessary make a note of it.
- Let the port number by the default
- Once the installation is complete, uncheck the Stack Builder prompt and click finish
- Now go to start menu, search and start pgAdmin 4
- Click on servers present on the pgAdmin homepage and choose Postgre SQL 10
- Enter the superuser password, and the dashboard will begin for your use
As the default repositories of Ubuntu contain Postgres packages, we can install it easily using the apt packaging system. Refresh the local package index and then install the Postgres packages and a -contrib package which adds additional functionality and utilities. The PostgreSQL software installation process is finished now.
PostgreSQL supports various data types, which includes:
- Boolean
- Numeric types
- Character types
- Temporal types
- Array
- UUID
- JSON
- store
- Special types such as geometric data and particular types
The ctid field exists in every PostgreSQL table. It is unique for every record in a table and denotes the turple location. It can be used to delete records. The thing to remember, we should only use ctid if we have absolutely no other unique identifier to use.
In PostgreSQL, table partitioning refers to splitting a large table into smaller sections. PostgreSQL supports list and range partitioning via table heritance. Users have to create each partition as a child table of the master table.
An explicit 'vacuum' call is made to update statistics in PostgreSQL. Users can also use the Analyze to perform so.
In PostgreSQL, the index is a common way for database performance enhancement. It allows the database server to find the retrieve specific rows faster compared to without index. It also adds overhead to the database system as a whole, so users have to implement them sensibly.
Indexes are special lookup tables that are used by the database search engine to speed up data retrieval. Simply defining, an index is a pointer to a specific data in a table.
Benefits of PostgreSQL
- Enterprise-class functions and performance with an open-source database management system with unlimited development possibilities.
- Superior development possibility with diverse community purposed modules.
- Store Procedure functions can be used for a server environment.
- It offers diverse indexing techniques.
- Availability of full-text search
- Diverse extension functions and replications