MIS Database Management Systems 2 — Questions and Answers
Question 1: Which type of JOIN returns only the rows where there is a match in both tables?
- LEFT JOIN
- RIGHT JOIN
- INNER JOIN (Correct answer)
- FULL OUTER JOIN
Correct answer: INNER JOIN
An INNER JOIN returns only the rows that have matching values in both tables being joined.
Question 2: What is the purpose of database normalization?
- To increase query execution speed by adding redundant data
- To reduce data redundancy and improve data integrity (Correct answer)
- To encrypt sensitive data in the database
- To replicate data across multiple servers
Correct answer: To reduce data redundancy and improve data integrity
Database normalization organizes tables to reduce data redundancy and improve data integrity by eliminating anomalies in insertion, update, and deletion operations.
Question 3: A Database Management System (DBMS) provides all of the following EXCEPT:
- Data storage and retrieval
- Concurrent user access control
- Network packet routing (Correct answer)
- Data backup and recovery
Correct answer: Network packet routing
Network packet routing is a function of network hardware and software, not a DBMS, which handles storage, retrieval, access control, and recovery.
Question 4: Which database language is used to define the structure of database objects like tables and indexes?
- Data Manipulation Language (DML)
- Data Control Language (DCL)
- Data Definition Language (DDL) (Correct answer)
- Transaction Control Language (TCL)
Correct answer: Data Definition Language (DDL)
Data Definition Language (DDL) includes commands like CREATE, ALTER, and DROP that define and modify the structure of database objects.
Question 5: In an Entity-Relationship (ER) diagram, a 'weak entity' is one that:
- Has no attributes
- Cannot exist without depending on another entity (Correct answer)
- Has too many relationships with other entities
- Contains only foreign key attributes
Correct answer: Cannot exist without depending on another entity
A weak entity cannot be uniquely identified by its own attributes alone and depends on a parent (strong) entity for its existence and identification.
Question 6: Which of the following best describes a NoSQL database?
- A database that uses only the SQL language for queries
- A non-relational database designed for flexible, scalable storage of unstructured or semi-structured data (Correct answer)
- A relational database optimized for read-heavy workloads
- A database that stores data in fixed-length records
Correct answer: A non-relational database designed for flexible, scalable storage of unstructured or semi-structured data
NoSQL databases are non-relational systems designed to handle flexible data models (document, key-value, column-family, graph) and horizontal scaling for large datasets.
Question 7: What is a 'deadlock' in the context of database concurrency?
- A situation where a database query takes too long to execute
- A state where two or more transactions are each waiting for the other to release a resource, causing a standstill (Correct answer)
- A backup process that locks the database for maintenance
- An error that occurs when invalid data is inserted into a table
Correct answer: A state where two or more transactions are each waiting for the other to release a resource, causing a standstill
A deadlock occurs when two or more transactions permanently block each other by each holding a resource the other needs, preventing any of them from completing.
MIS Database Management Systems 2
Which type of JOIN returns only the rows where there is a match in both tables?