DBMS MCQ

What is a Database?

A database is a collection of related data which represents some aspect of the real world. A database system is designed to be built and populated with data for a certain task.

DBMS allows users to create their own databases as per their requirement. The term “DBMS” includes the user of the database and other application programs. It provides an interface between the data and the software application.

In this section, we are going to cover some of the basic questions based on DBMS, which are frequently asked during an interview. Here we will try to cover almost all the topics related to DBMS.

41) The characteristics of the table in second normal form (2NF) is:
A. Eliminates any hidden dependency
B. Have a composite key
C. Eliminate the possibility of insertion anomalies
D. None of the above

Answer: a
Explanation: The relation in the second normal form should be in the first normal form and doesn’t have any partial dependency.

42) Which of the following statement is false about the third normal form (3NF)?
A. It is used to remove data duplication.
B. It contains transitive partial dependency.
C. It is used to achieve data integrity.
D. All of the above

Answer: b
Explanation: A relation will be in 3NF if it is in 2NF, and there should not be a transitive dependency for non-prime attributes.

43) Which forms are based on the concept of functional dependency?
A. 1NF
B. 2NF
C. 3NF
D. 4NF

Answer: c
Explanation: A relation is in third normal form if it holds at least one of the following conditions for every non-trivial functional dependency X ? Y.
• X is a super key.
• Y is a prime attribute, i.e., each element of Y is part of some candidate key.

44) Which of the following is a bottom-up approach to design a database by examining the relationship between attributes?
A. Functional dependency
B. Database modeling
C. Normalization
D. Decomposition

Answer: c
Explanation: Normalisation is the process of removing redundancy and unwanted data.

45) Which of the following header must be included in the java program to establish database connectivity using JDBC?
A. Import java.sql.*;
B. Import java.sql.odbc.jdbc.*;
C. Import java.jdbc.*;
D. Import java.sql.jdbc.*;

Answer: a
Explanation: The Java program must import java.sql.*, which contains the interface definitions for the functionality provided by JDBC.

46) Which of the following is used to access large objects from a database?
A. setBlob()
B. getBlob()
C. getClob()
D. All of the above

Answer: d
Explanation: These are the predefined functions in SQL to access the large object from a database.

47) DriverManager.getConnection(……. , ……. , ……..)
Fill in the blanks with valid options.
A. URL or machine name where the server runs, Password, User ID
B. Password, URL or machine name where the server runs, User ID
C. URL or machine name where the server runs, User ID, Password
D. User ID, Password, URL or machine name where the server runs

Answer: c
Explanation: This connection method is used to open the database because a database must be opened first before performing any action.

48) Which of the following statement is used to invoke the function in SQL?
A. Connection statement
B. Callable statements
C. Prepared Statements
D. All of the above

Answer: b
Explanation: This interface is provided by JDBC that allows invocation of SQL stored procedures and functions.

49) Which of the following is a bottom-up approach that combines two or more low-level entities into a high-level entity?
A. Generalization
B. Specialization
C. Aggregation
D. All of the above

Answer: a
Explanation: Specialization is the opposite of generalization that break high-level entities into low-level entities.

50) Which keyword is used to access records in file organization?
A. Primary key
B. Foreign key
C. Candidate key
D. Super key

Answer: a
Explanation: The collection of records is known as a file.