Here in this post we will discuss DBMS most asked questions with answer, frequently asked DBMS question with answers. As a CSE student with a great deal of interview failure experience, I’ve put together a list of the most common DBMS interview questions in the hopes of assisting future candidates.
Here below are the top 100 DBMS most asked questions with answers:
Putting together a list of the top 100 DBMS most asked questions and answers for fundamental DBMS (Database Management System) in Computer Science Engineering (CSE) might be time-consuming, but here’s a shortened version that covers a variety of topics:
- What is a Database?
- A database is a structured collection of data that is organized and stored electronically.
- What is DBMS?
- DBMS (Database Management System) is software that manages databases, providing an interface for users to interact with and manipulate data.
- What are the advantages of DBMS?
- Advantages include data consistency, data integrity, data security, data sharing, and efficient data management.
- What are the different types of DBMS?
- Types include relational DBMS (RDBMS), object-oriented DBMS (OODBMS), object-relational DBMS (ORDBMS), and NoSQL databases.
- What is a table in a database?
- A table is a collection of related data organized into rows and columns.
- What is a record?
- A record is a single instance or row within a table, containing data fields or attributes.
- What is a field in a database?
- A field is a single data element within a record, representing a specific attribute or property.
- What is a primary key?
- A primary key is a unique identifier for each record in a table, used to ensure data integrity and facilitate data retrieval.
- What is a foreign key?
- A foreign key is a field in a table that links to the primary key of another table, establishing a relationship between the two tables.
- What is normalization?
- Normalization is the process of organizing data in a database to minimize redundancy and dependency, improving data integrity and efficiency.
- Explain the different normal forms.
- Normal forms include First Normal Form (1NF), Second Normal Form (2NF), Third Normal Form (3NF), Boyce-Codd Normal Form (BCNF), and Fourth Normal Form (4NF).
- What is an index?
- An index is a data structure that improves the speed of data retrieval operations on a database table by providing quick access to specific rows.
- What is a query?
- A query is a request for information from a database, typically in the form of a structured query language (SQL) statement.
- What is SQL?
- SQL (Structured Query Language) is a programming language used to manage and manipulate relational databases.
- What are the different types of SQL commands?
- Types include Data Definition Language (DDL), Data Manipulation Language (DML), Data Control Language (DCL), and Transaction Control Language (TCL) commands.
- What is the difference between DROP and TRUNCATE commands?
- DROP command removes a table and its data permanently, while TRUNCATE command deletes all rows from a table but keeps the table structure intact.
- What is a view in SQL?
- A view is a virtual table generated by a query, presenting data from one or more tables in a specific format.
- What is a stored procedure?
- A stored procedure is a precompiled set of SQL statements stored in the database and executed as a single unit.
- What is a trigger?
- A trigger is a database object that automatically executes in response to specified events, such as insertions, deletions, or updates.
- Explain ACID properties in DBMS.
- ACID stands for Atomicity, Consistency, Isolation, and Durability, which are properties that ensure database transactions are reliable and maintain data integrity.
- ACID stands for Atomicity, Consistency, Isolation, and Durability, which are properties that ensure database transactions are reliable and maintain data integrity.
- What is concurrency control in DBMS?
- Concurrency control is the process of managing simultaneous access to shared data in a multi-user database system to prevent conflicts and maintain consistency.
- What is a deadlock?
- A deadlock occurs when two or more transactions are waiting for each other to release resources, resulting in a state where no progress can be made.
- What is a schema?
- A schema is a collection of database objects, including tables, views, indexes, and constraints, that defines the structure and organization of a database.
- What is data integrity?
- Data integrity ensures the accuracy, consistency, and reliability of data stored in a database, preventing data corruption or loss.
- What is referential integrity?
- Referential integrity ensures that relationships between tables are maintained by enforcing constraints, such as foreign key constraints, to prevent orphaned or invalid data.
- What is data redundancy?
- Data redundancy occurs when the same data is stored in multiple places within a database, leading to inefficiency and increased storage requirements.
- What is data normalization?
- Data normalization is the process of organizing data in a database to minimize redundancy and dependency, improving data integrity and efficiency.
- What is denormalization?
- Denormalization is the process of intentionally introducing redundancy into a database design to improve performance by reducing the need for joins and data retrieval operations.
- What is a join in SQL?
- A join is a SQL operation that combines rows from two or more tables based on a related column between them.
YOU MIGHT ALSO LIKE :
PAYPAL INTERVIEW AND CODING QUESTIONS
- A join is a SQL operation that combines rows from two or more tables based on a related column between them.
- What are the different types of joins?
- Types include INNER JOIN, LEFT JOIN (or LEFT OUTER JOIN), RIGHT JOIN (or RIGHT OUTER JOIN), and FULL JOIN (or FULL OUTER JOIN).
- What is a subquery?
- A subquery is a query nested within another query, allowing for more complex data retrieval and manipulation operations.
- What is a transaction in DBMS?
- A transaction is a logical unit of work that consists of one or more database operations, such as insertions, deletions, or updates, that must be executed as a single unit.
- What are the properties of a transaction (ACID)?
- ACID properties ensure that transactions are Atomic, Consistent, Isolated, and Durable, maintaining data integrity and reliability.
- What is a composite key?
- A composite key is a combination of two or more columns that uniquely identify each row in a table.
- What is a data warehouse?
- A data warehouse is a centralized repository of integrated data from multiple sources, designed for analysis and reporting.
- What is OLAP?
- OLAP (Online Analytical Processing) is a technology used for analyzing multidimensional data from data warehouses to facilitate business intelligence and decision-making.
- What is OLTP?
- OLTP (Online Transaction Processing) is a technology used for managing transaction-oriented applications, such as e-commerce or banking systems, that require high throughput and low response times.
- What is a database trigger?
- A database trigger is a stored program that automatically executes in response to specified events, such as insertions, deletions, or updates, on a table.
- What is a constraint in DBMS?
- A constraint is a rule defined on a database column to enforce data integrity and validity, such as primary key, foreign key, unique, and check constraints.
- What is the difference between clustered and non-clustered index?
- A clustered index determines the physical order of rows in a table, while a non-clustered index does not affect the physical order of rows but provides a separate data structure for efficient data retrieval.
- What is a data dictionary?
- A data dictionary is a centralized repository of metadata that describes the structure, organization, and relationships of data in a database.
- What is a database transaction log?
- A database transaction log is a file that records all changes made to the data in a database, enabling recovery and rollback operations in case of system failures or errors.
- What is a deadlock in DBMS?
- A deadlock occurs when two or more transactions are waiting for each other to release resources, resulting in a state where no progress can be made.
- What is database normalization?
- Database normalization is the process of organizing data in a database to minimize redundancy and dependency, improving data integrity and efficiency.
- What is an entity-relationship diagram (ERD)?
- An entity-relationship diagram is a visual representation of the entities (tables), attributes (columns), and relationships between them in a database.
- What is a star schema?
- A star schema is a type of database schema used in data warehousing that consists of one or more fact tables connected to multiple dimension tables in a star-like structure.
- What is a snowflake schema?
- A snowflake schema is a type of database schema used in data warehousing that extends the star schema by normalizing dimension tables into multiple levels of hierarchy.
- What is a data mart?
- A data mart is a subset of a data warehouse that is focused on a specific business function or department, containing aggregated and summarized data for analysis and reporting.
- What is the difference between OLAP and OLTP?
- OLAP (Online Analytical Processing) is used for analyzing multidimensional data from data warehouses, while OLTP (Online Transaction Processing) is used for managing transaction-oriented applications that require high throughput and low response times.
- What is data mining?
- Data mining is the process of discovering patterns, trends, and insights from large datasets using statistical, machine learning, and other analytical techniques.
- What is a surrogate key?
- A surrogate key is a unique identifier generated by the database system, typically used as a primary key when natural keys are unavailable or unsuitable.
- What is a materialized view?
- A materialized view is a precomputed summary table derived from one or more base tables, providing faster access to aggregated or computed data.
- What is a database schema?
- A database schema is a collection of database objects, including tables, views, indexes, and constraints, that defines the structure and organization of a database.
- What is a data warehouse architecture?
- A data warehouse architecture defines the components, processes, and technologies used to design, build, and manage a data warehouse, including data sources, ETL processes, storage, and access layers.
- What is a distributed database?
- A distributed database is a database system that consists of multiple interconnected databases distributed across different locations or nodes, providing scalability, availability, and fault tolerance.
- What is an ETL process?
- ETL (Extract, Transform, Load) is a process used to extract data from multiple sources, transform it into a consistent format, and load it into a data warehouse for analysis and reporting.
- What is database replication?
- Database replication is the process of copying and distributing data from one database to another to ensure consistency, availability, and fault tolerance.
- What is a data warehouse model?
- A data warehouse model is a logical or physical representation of the structure and organization of data in a data warehouse, including dimensional models (star schema, snowflake schema) and normalized models.
- What is a database index?
- A database index is a data structure that improves the speed of data retrieval operations on a database table by providing quick access to specific rows based on indexed columns.
- What is database sharding?
- Database sharding is a technique used to horizontally partition data across multiple databases or nodes to improve scalability, performance, and availability.
- What is a database trigger?
- A database trigger is a stored program that automatically executes in response to specified events, such as insertions, deletions, or updates, on a table.
- What is data replication in DBMS?
- Data replication is the process of copying and distributing data from one database to another to ensure consistency, availability, and fault tolerance.
- What is a database connection pool?
- A database connection pool is a cache of database connections maintained by an application server to improve performance and scalability by reusing connections rather than establishing new ones for each request.
- What is a database deadlock?
- A database deadlock occurs when two or more transactions are waiting for each other to release resources, resulting in a state where no progress can be made.
- What is a database backup?
- A database backup is a copy of data stored in a database at a specific point in time, used to restore data in case of system failures, errors, or data loss.
- What is data warehousing in DBMS?
- Data warehousing is the process of collecting, storing, and analyzing data from multiple sources to facilitate business intelligence, decision-making, and reporting.
- What is a database query optimization?
- Database query optimization is the process of improving the performance of database queries by analyzing query execution plans, indexes, statistics, and other factors to reduce response times and resource usage.
- What is database mirroring?
- Database mirroring is a high-availability technique used to maintain a redundant copy of a database on a separate server to ensure failover and disaster recovery capabilities.
- What is a database transaction log?
- A database transaction log is a file that records all changes made to the data in a database, enabling recovery and rollback operations in case of system failures or errors.
- What is database security?
- Database security encompasses measures and protocols implemented to protect data stored in a database from unauthorized access, tampering, or theft.
- What is a database user?
- A database user is an individual or application that has been granted access to a database and is authorized to perform specific operations, such as querying, inserting, updating, or deleting data.
- What is a database server?
- A database server is a computer or software application that provides database services to clients, managing data storage, retrieval, and manipulation operations.
- What is database clustering?
- Database clustering is a technique used to improve scalability and availability by distributing database services across multiple servers or nodes in a cluster.
- What is database partitioning?
- Database partitioning is a technique used to divide large tables or indexes into smaller, more manageable partitions based on specific criteria, such as ranges or hash values.
- What is database caching?
- Database caching is a technique used to improve performance by storing frequently accessed data in memory or a cache, reducing the need for disk-based I/O operations.
- What is a database schema migration?
- Database schema migration is the process of updating or modifying the structure of a database, such as adding, removing, or modifying tables, columns, or constraints.
- What is a database deadlock?
- A database deadlock occurs when two or more transactions are waiting for each other to release resources, resulting in a state where no progress can be made.
- What is database encryption?
- Database encryption is the process of encoding data stored in a database to protect it from unauthorized access or disclosure, using cryptographic algorithms and keys.
- What is a database audit?
- A database audit is a process of monitoring and recording database activities, such as logins, logouts, queries, and transactions, to ensure compliance, security, and accountability.
- What is a database migration?
- Database migration is the process of moving data from one database system or environment to another, typically to upgrade or consolidate systems, or to transition to a new platform or architecture.
- What is database recovery?
- Database recovery is the process of restoring a database to a consistent state after a system failure, error, or data loss, using backups, transaction logs, and recovery mechanisms.
- What is a database connection pool?
- A database connection pool is a cache of database connections maintained by an application server to improve performance and scalability by reusing connections rather than establishing new ones for each request.
- A database connection pool is a cache of database connections maintained by an application server to improve performance and scalability by reusing connections rather than establishing new ones for each request.
- What is database partitioning?
- Database partitioning is a technique used to divide large tables or indexes into smaller, more manageable partitions based on specific criteria, such as ranges or hash values.
- What is database optimization?
- Database optimization is the process of improving the performance and efficiency of a database system by analyzing and fine-tuning various factors, such as indexes, queries, storage, and configuration settings.
- What is database replication?
- Database replication is the process of copying and distributing data from one database to another to ensure consistency, availability, and fault tolerance.
- What is database mirroring?
- Database mirroring is a high-availability technique used to maintain a redundant copy of a database on a separate server to ensure failover and disaster recovery capabilities.
- What is database archiving?
- Database archiving is the process of moving infrequently accessed or historical data from active databases to secondary storage or archival systems to free up space and improve performance.
- What is a database audit trail?
- A database audit trail is a log or record of database activities, such as logins, logouts, queries, and transactions, used for compliance, security, and forensic purposes.
- What is database locking?
- Database locking is a mechanism used to control access to shared data in a multi-user database system, preventing conflicts and ensuring consistency by temporarily blocking other transactions from accessing the same data.
- What is database normalization?
- Database normalization is the process of organizing data in a database to minimize redundancy and dependency, improving data integrity and efficiency.
- What is database denormalization?
- Database denormalization is the process of intentionally introducing redundancy into a database design to improve performance by reducing the need for joins and data retrieval operations.
- What is database caching?
- Database caching is a technique used to improve performance by storing frequently accessed data in memory or a cache, reducing the need for disk-based I/O operations.
- What is database clustering?
- Database clustering is a technique used to improve scalability and availability by distributing database services across multiple servers or nodes in a cluster.
- What is database replication?
- Database replication is the process of copying and distributing data from one database to another to ensure consistency, availability, and fault tolerance.
- What is database sharding?
- Database sharding is a technique used to horizontally partition data across multiple databases or nodes to improve scalability, performance, and availability.
- What is database connection pooling?
- Database connection pooling is a cache of database connections maintained by an application server to improve performance and scalability by reusing connections rather than establishing new ones for each request.
- What is database backup and recovery?
- Database backup and recovery are processes used to protect and restore data in a database in case of system failures, errors, or data loss, using backups, transaction logs, and recovery mechanisms.
- What is database monitoring?
- Database monitoring is the process of observing and analyzing database performance, availability, and resource usage to identify and address issues, optimize performance, and ensure reliability.
- What is database performance tuning?
- Database performance tuning is the process of analyzing and optimizing various factors, such as indexes, queries, storage, and configuration settings, to improve the performance and efficiency of a database system.
- What is database security?
- Database security encompasses measures and protocols implemented to protect data stored in a database from unauthorized access, tampering, or theft.
Frequently asked DBMS interview questions
1. What is DBMS ? How it is Different from Data Structures.
2. Difference Between Database and Database Management System ?
3. Main Memory and Secondary Memory.
4. Basic Functionality and Advantages of DBMS i.e. Data Retrieve , Delete , Insert
(Functionality) and Remove Redundancy , Easy access ( Advantages)
5. DBMS Two Level and Three Level Architecture.
6. Entity Relationship Model (ER Model , Know the Basics i.e What is Entity , Attributes
and Cardinality) (Hint : They won’t ask You to make Complex ER diagram)
7. Relational Model ( Difference b/w ER model and Relational Model)
8. All type of Keys in Relational Model ( Primary Key , Super Key , Candidate Key , Foreign
Key) (Hint : Important)
9. Armstrong Axioms and All type of Functional Dependencies (Transitive and Relative)
10. Database Anomalies ( Insert , Delete and Update)
11. Normalization -> What is Normalization ? Why do we need Normalization ?
12. All the Types of Normalization , 1NF , 2NF , 3NF and BCNF. (Hint : They won’t ask you
to Convert the Functions into 1NF , 2NF and All , Just Know the Basics of Each Normal
Form & It Would Be Better if you Understand Every NF Form with an Example)
(Important topic)
13. SQL Queries ( Learn with one example of Each Query , Not Much, Best Resource :
SQL w3 Resource )
14. File Structures in Database ( Indexing , Sparse Indexing , B- Tree , B+ trees) (Source
GFG)
15. Transactions , Operations of Transactions , Transaction’s ACID Properties
(Important)
16. State of Transactions i.e Committed , partially Committed
17. Concurrency Control , Lock and all over Transactions
What type of DBMS questions are asked in an interview?
DBMS interview questions often cover keys, constraints, functional dependencies, normalisation, transactions, joins, and SQL queries.
SUMMARY ON top DBMS most asked questions
In this post, we have attempted to summarise and compile 100 of the most asked DBMS questions with answers , in the hopes that this may assist you in passing your next interview.More interview questions visit core subjects interview questions