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Commonly asked DBMS interview questions for intermediate level
A database management system is a system tool that enables effective and convenient data storage, access, manipulation, and sharing. It facilitates access and storage of linked data. Data Dictionary Management, Database Access Languages, Data Transformation and Presentation, Data Storage Management, Multi-User Access Control, Data Integrity Management, Database Communication Interfaces, Application Programming Interfaces, and Backup and Recovery Management are just a few of the functionalities it includes.
We'll go over the most typical DBMS interview queries in this post to help you be ready for meetings with major MNCs. Keys, constraints, functional dependencies, normalization, transactions, joins, and SQL queries are common topics for DBMS interview questions.
Let's move on to some of the most common DBMS interview queries.
1) What is a DBMS, and why is it preferable to a conventional file system?
A software program used to manage, store, and retrieve data from a database is known as a DBMS, or database management system. With capabilities like data integrity, concurrency control, and backup and recovery procedures, it offers a solution to organize and handle vast volumes of data safely and effectively. Better data organization, higher data consistency, improved data security, better data sharing and access, and better data integrity and dependability are all benefits of utilizing a DBMS over a conventional file system.
2) Why is normalization crucial for databases? What does it entail?
Data in a database are organized by a process called normalization that lessens dependencies and redundant data. A massive table must be divided into smaller, more manageable tables, and connections must be made between them. Because it increases data consistency, minimizes data redundancy, and helps prevent data anomalies including update anomalies, deletion anomalies, and insertion anomalies, normalization is crucial for databases.
3) What is the distinction between a primary key and a foreign key?
A table's records are uniquely identified by their primary keys. It is used to guarantee referential integrity and make sure that every entry in the database is distinct. A field in a database that refers to the primary key of another table is known as a foreign key, on the other hand. It is utilized to fortify referential integrity between two tables and construct a link between them.
4) What does a database index accomplish, and how does it boost performance?
A database's index is a data structure that accelerates data retrieval processes. It functions by making a second table with a duplicate of the information in the original table but organized differently. The index is used to discover the data more rapidly when a query is run, which enhances database speed.
5) What exactly is a transaction, and what characteristics mark a successful transaction?
A database transaction is a series of database activities that are handled as one cohesive piece of work. Data consistency and dependability are ensured via transactions, which have four essential characteristics known as the ACID properties: atomicity, consistency, isolation, and durability. A good transaction is one that protects data integrity, is simple to recover from, is effective, and complies with system and user requirements.
6) Which SQL join types are there, and when would you use each one?
The many join types in SQL are complete outer join, left outer join, right outer join, and inner join. Inner join only returns rows with matching values in both tables, full outer join only returns rows from both tables, left outer join only returns rows from the left table, right outer join only returns rows from the right table, and right outer join only returns rows from the right table.
7) What is ACID, and how do database transactions relate to it?
The four essential characteristics of a database transaction are atomicity, consistency, isolation, and durability, sometimes known as ACID. A transaction is viewed as a single unit of work with atomicity, and is either fully completed or not at all. Consistency guarantees that both before and after the transaction, the database is still in a usable condition. Concurrent transactions are prevented from interfering with one another through isolation. Durability guarantees that once a transaction is committed, its modifications are irreversible and lasting.
8)What is a trigger in a database and how is it used?
When a given database event occurs, such as a table update, insert, or delete operation, a trigger—a special kind of stored procedure—automatically executes. Business rules, auditing, logging, enforcing referential integrity, and automating certain database processes are all carried out via triggers. They can be programmed to run either ahead of or following the database event.
9)How do stored procedures and functions differ from one another?
A precompiled collection of SQL statements that are saved in the database and may be invoked by a program or user are known as stored procedures. Data security, network traffic reduction, and performance enhancement are all achieved through the usage of stored processes. They may also be utilized to carry out difficult data processing tasks and enforce business standards. On the other hand, a function is a database item that, in response to input parameters, returns a single value. Functions can be used to conduct computations or alter data, and they can be called from within SQL statements or included in SQL expressions.
10)What is a view in a database and how is it used?
In a database, a view is a virtual table created based on the output of a SELECT command. Views are used to present a condensed or tailored picture of the data in a database without revealing the complexity or underlying data structure. They may also be used to ensure data security by restricting which people or organizations have access to which data.
DBMS (Database Management System) is a crucial component of contemporary computing, to sum up. Data storage, access, and administration are significantly impacted by the field of database management. In IT job interviews, DBMS-related questions are frequently asked.
The most typical DBMS interview questions have been covered in the article, ranging from fundamental ideas like the distinction between a database and a table to more complex subjects like normalization, indexing, and transactions. IT workers might be better prepared for DBMS-related job interviews by being familiar with these questions.
The article offers a thorough review of some of the most typical DBMS interview questions, and by understanding these ideas, IT professionals may improve their chances of finding employment.
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