Top 200+ Most Asked DBMS Interview Questions

A strategic collection of frequently asked DBMS interview questions covering everything from fundamentals and normalization to concurrency control and modern NoSQL architectures. Designed for technical interview mastery.

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1.What is a Database?

2.What is a Database Management System (DBMS)?

3.What are the main advantages of using a DBMS?

4.Why do we need DBMS?

5.What is the difference between DBMS and file system?

6.What are the different types of DBMS?

7.What is a database instance?

8.What is a data dictionary?

9.What is Database Admin & its Functions?

10.What is the role of a Database Administrator (DBA)?

11.What is RDBMS?

12.What is the difference between DBMS and RDBMS?

13.How is RDBMS stored in memory?

14.What is the meaning of 'Relational' in RDBMS?

15.What are the different types of relationships in databases?

16.What is Degree of Relation (1:1, 1:M, M:M)?

17.What is Database Tier-2/Tier-3 Architecture?

18.What is Data abstraction in DBMS?

19.What are the three levels of data abstraction?

20.What is the difference between logical and physical database design?

21.What is Instance, Schema, and Sub-Schema?

22.What are Database Languages (DDL, DML, DCL, TCL)?

23.What is SQL and why is it important?

24.What are the different types of SQL commands?

25.What is the difference between SQL and MySQL?

26.What is a Primary Key?

27.What is a Foreign Key?

28.What is a candidate key?

29.What is an Alternate key?

30.What is a Super Key?

31.What is a Composite key?

32.What is a Secondary Key?

33.What is the difference between primary key and unique key?

34.What is a UNIQUE Key?

35.What is the difference between Primary Key and UNIQUE Key?

36.What are constraints in DBMS?

37.What is referential integrity?

38.What is Referential Integrity Rule in RDBMS?

39.What is NOT NULL constraint?

40.What is Default Constraint?

41.What are aggregate constraints?

42.What is a foreign key constraint action?

43.What is a database schema?

44.What is Database Schema (Physical vs Logical)?

45.What are Schema Diagrams?

46.What is an Entity-Relationship (ER) diagram?

47.What is the difference between entity and attribute?

48.What is a weak entity set?

49.What is ER to Relational Model conversion?

50.What are the best practices for database design?

51.What is normalization and why is it important?

52.What is the purpose of Normalization?

53.What are 3 anomalies resolved by normalization?

54.What is First Normal Form (1NF)?

55.What is Second Normal Form (2NF)?

56.What is Third Normal Form (3NF)?

57.What is Boyce-Codd Normal Form (BCNF)?

58.What is denormalization and when is it used?

59.What is Denormalization?

60.What is database normalization and its objectives?

61.What is functional dependency?

62.What is Functional Dependency and its types?

63.What is Trivial Functional Dependency?

64.What is Non-Trivial Functional Dependency?

65.What is Fully-Functional Dependency?

66.What is Partial Functional Dependency?

67.What is Transitive Dependency?

68.What is an index and how does it work?

69.What is Index in DBMS & its types?

70.What is Indexing in SQL?

71.What is the difference between clustered and non-clustered index?

72.What is a Clustered Index?

73.What is a Non-Clustered Index?

74.What is the difference between Clustered and Non-Clustered Index?

75.What is a B-tree index?

76.What is the difference between B-tree and B+ tree?

77.What is a bitmap index?

78.What is a composite index?

79.What is a covering index?

80.What is hashing in DBMS?

81.What is Index Fragmentation?

82.What are Joins in SQL?

83.What are the different types of joins in SQL?

84.What is INNER JOIN?

85.What is LEFT JOIN?

86.What is RIGHT JOIN?

87.What is FULL JOIN?

88.What is Self Join?

89.What is Cross Join?

90.What is the difference between INNER JOIN and OUTER JOIN?

91.What is the difference between WHERE and HAVING clause?

92.What is the HAVING clause and when is it used?

93.What is GROUP BY in SQL?

94.What is the difference between Group By and Order By?

95.What is the use of LIMIT in SQL?

96.What is UNION and UNION ALL?

97.What is the difference between UNION and UNION ALL?

98.What is the difference between IN and EXISTS?

99.What is the use of EXISTS in SQL?

100.What is a subquery in SQL?

101.What is Subquery?

102.What is Nested Query?

103.What is Correlated Subquery?

104.What is a correlated subquery?

105.What is a View in DBMS?

106.What is View in SQL?

107.What is the difference between View and Table?

108.What is a materialized view?

109.What is the difference between view and materialized view?

110.What is a stored procedure?

111.What is Stored Procedure?

112.What is the difference between Function and Stored Procedure?

113.What is the Difference Between Stored Procedure and Function in SQL?

114.What is a stored function?

115.What is a trigger in DBMS?

116.What is Trigger in SQL?

117.What is the difference between a trigger and stored procedure?

118.What is a database trigger use case?

119.What is a Cursor?

120.What is a database cursor?

121.What is a transaction in DBMS?

122.What is a Transaction?

123.What is a Transaction in SQL?

124.What are ACID properties in DBMS?

125.What is the ACID Property in SQL?

126.How to implement Atomicity in Transactions?

127.What is the function of the Atomicity property?

128.What is the difference between COMMIT and ROLLBACK?

129.What is the difference between COMMIT and ROLLBACK in SQL?

130.What is Savepoint in SQL?

131.What is a savepoint?

132.What are the important terms in Transaction Management (Commit, Rollback, Savepoint)?

133.What is Concurrent Transaction?

134.What is concurrency control in DBMS?

135.What are the problems of Concurrent transactions?

136.What are the advantages of Concurrent transactions?

137.What is Conflict Operation in Schedules?

138.What are the different types of Schedules (Serial, Complete, Recoverable, Cascadeless, Strict)?

139.What is 2-Phase Locking Protocol?

140.What are the different types of database locks?

141.What is locking and its types?

142.What is the difference between shared and exclusive locks?

143.What is Shared Lock?

144.What is Exclusive Lock?

145.What is two-phase locking?

146.What is a deadlock in DBMS?

147.How to Prevent Deadlock (Mutual Exclusion, Hold and Wait, No PreEmption, Circular wait)?

148.What are other Techniques to prevent Deadlock (Timestamp based)?

149.What is Wait-Die Scheme?

150.What is Wound-Wait Scheme?

151.What is Timeout Based Scheme?

152.What is Starvation and its reason?

153.What is Deadlock Recovery?

154.How to Avoid Deadlocks in SQL?

155.What is Storage System in DBMS?

156.What is File Structure in DBMS?

157.What is the difference between DELETE and TRUNCATE?

158.What is the difference between DELETE, TRUNCATE, and DROP?

159.What is the difference between Drop, Delete, and Truncate?

160.What is the disadvantage of the DROP TABLE command?

161.What is the difference between DROP and TRUNCATE?

162.What is CTE (Common Table Expression)?

163.What is a Common Table Expression (CTE)?

164.What is Temporary Table in SQL?

165.What are temporary tables?

166.What is the difference between Temporary Table and CTE?

167.What is Window Function in SQL?

168.What is a window function in SQL?

169.What is the difference between ROW_NUMBER(), RANK(), and DENSE_RANK()?

170.What is CASE Statement in SQL?

171.What is the CASE statement in SQL?

172.What is COALESCE in SQL?

173.What is NVL Function in SQL?

174.What is query optimization?

175.What is Query Optimization?

176.How to Optimize SQL Queries?

177.What is Query Execution Plan?

178.How to Improve Query Performance?

179.What is data warehousing?

180.What is the difference between OLTP and OLAP?

181.What is a data mart?

182.What is data mining?

183.What is ETL in data warehousing?

184.What is database partitioning?

185.What is Table Partitioning?

186.What is database sharding?

187.What are the different types of backup strategies?

188.What is database recovery and its types?

189.What is a checkpoint in DBMS?

190.What is a transaction log?

191.What is SQL injection and how to prevent it?

192.What are SQL Privileges?

193.What is data redundancy and how to reduce it?

194.What is data independence?

195.What is database mirroring?

196.What is database replication?

197.What is database cache?

198.What is a timestamp in DBMS?

199.What is serializability?

200.What is SQL vs NoSQL?

201.What is the difference between SQL and NoSQL?

202.Which Modern Database Is Right for Your Use Case?

203.What is CAP theorem?

204.What is the difference between ACID and BASE?

205.What is In-memory Database?

206.What is Graph Database?

207.What are Scaling Patterns?

208.What is Scaling RDBMS and NoSQL?

209.What is Master-Slave Architecture?

210.What is Master-Slave vs Master-Master?