This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Computer Science > Class 12 Computer Science Chapter 3 Database Management Systems – Quiz 22 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Computer Science Chapter 3 Database Management Systems Quiz 22 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. An entity set is: A) A table with no primary key. B) A collection of similar entities. C) A set of attributes. D) A relationship between entities. Show Answer Correct Answer: B) A collection of similar entities. 2. What does data dictionary management in a DBMS do? A) Defines data elements and their relationships. B) Encrypts all data transmissions. C) Manages user passwords. D) Schedules system backups. Show Answer Correct Answer: A) Defines data elements and their relationships. 3. If you were collecting and storing information about your music collection, an album would be considered a/an ..... A) Attribute. B) Instance. C) Entity. D) Relation. Show Answer Correct Answer: C) Entity. 4. Which of the following is NOT a component of a DBMS? A) Data dictionary. B) Spreadsheet module. C) Query processor. D) Database engine. Show Answer Correct Answer: B) Spreadsheet module. 5. Which feature of a DBMS helps maintain data consistency and prevents errors? A) Logical schema. B) Data integrity controls. C) Data redundancy. D) File storage system. Show Answer Correct Answer: B) Data integrity controls. 6. A composite key is: A) A backup of the primary key. B) A key made up of multiple columns. C) The largest key in the database. D) A key from another table. Show Answer Correct Answer: B) A key made up of multiple columns. 7. What is a key feature of NoSQL databases? A) Use of SQL for querying. B) ACID compliance. C) Scalability and flexibility. D) Structured data storage. Show Answer Correct Answer: C) Scalability and flexibility. 8. Subtypes should be used when: A) There are attributes that apply to some but not all instances of an entity type. B) Supertypes relate to objects outside the business. C) The instances of a subtype do not participate in a relationship that is unique to that subtype. D) A recursive relationship is needed. Show Answer Correct Answer: A) There are attributes that apply to some but not all instances of an entity type. 9. Which DBMS does DoorDash use for low-latency data processing? A) Couchbase. B) HBase. C) CockroachDB. D) MySQL. Show Answer Correct Answer: C) CockroachDB. 10. What is the purpose of the INTERSECT operation in relational algebra? A) Retrieve common rows from two tables. B) Combine rows from different tables. C) Sort the table in descending order. D) Remove unwanted columns from a table. Show Answer Correct Answer: A) Retrieve common rows from two tables. 11. What is a major consequence of data redundancy in file systems? A) Increased security. B) Data inconsistency and anomalies. C) Easier program maintenance. D) Simplified system administration. Show Answer Correct Answer: B) Data inconsistency and anomalies. 12. A database management system automatically prints all reports once you log in. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 13. Drop table statement A) Deletes the table structure along with the table data. B) Works whether or not referential integrity constraints would be violated. C) Is not an SQL statement. D) Deletes the table structure only. Show Answer Correct Answer: A) Deletes the table structure along with the table data. 14. What is a common issue with files? A) Fast lookups. B) Role-based access. C) Automatic backups. D) Redundancy and inconsistency. Show Answer Correct Answer: D) Redundancy and inconsistency. 15. ..... :User interface layer. A) Integration Tier. B) Business Logic Tier. C) Presentation Tier. D) Data Tier. Show Answer Correct Answer: C) Presentation Tier. 16. Which ERD is best for a university database with Students, Professors, Courses, and Enrollments? A) One table storing everything. B) Separate entities linked with keys and relationships. C) Students and Courses combined in one table. D) Professors stored only as attributes of Courses. Show Answer Correct Answer: B) Separate entities linked with keys and relationships. 17. What is a collection of concepts that can be used to describe the structure of a database? A) Data Model. B) Schema. C) Instance. D) None of the above. Show Answer Correct Answer: A) Data Model. 18. Which of the following SQL query is correct for selecting the name of staffs from 'tblstaff' table where salary is 15, 000 or 25, 000? A) SELECT sname from tblstaff WHERE salary IN (15000, 25000);. B) SELECT sname from tblstaff WHERE salary BETWEEN 15000 AND 25000;. C) Both a and b. D) None of the above. Show Answer Correct Answer: A) SELECT sname from tblstaff WHERE salary IN (15000, 25000);. 19. The term "data independence" in DBMS refers to: A) The ability to store data offline. B) Data stored in multiple locations. C) Data that does not change over time. D) The separation of data from the applications. Show Answer Correct Answer: D) The separation of data from the applications. 20. Why is it important for information to be accurate, relevant, and timely in organizations? A) To reduce the need for computer models. B) To increase the number of file folders. C) To make good decisions that affect the organization. D) To ensure that data is stored in flat files. Show Answer Correct Answer: C) To make good decisions that affect the organization. 21. Which of the following is NOT a type of SQL operation? A) SELECT. B) COMPILE. C) INSERT. D) DELETE. Show Answer Correct Answer: B) COMPILE. 22. What is a key feature of relational DBMS? A) Tables with relationships B) Single file storage C) No data relationships D) Only text data A) Flat file storage. B) No relationships between data. C) A) Tables with relationships. D) Only numeric data. Show Answer Correct Answer: C) A) Tables with relationships. 23. Which of the following is an example of a Database-System Application? A) Web Browser. B) Inventory Management System. C) Word Processor. D) Photo Editing Software. Show Answer Correct Answer: B) Inventory Management System. 24. Among the following Operating Systems, which one describes the first operating systems for the personal computer that could be operated using the command prompt? A) Linux operating system. B) Disk Operating System (DOS). C) Macintosh operating system (MacOS). D) Windows operating system. Show Answer Correct Answer: B) Disk Operating System (DOS). 25. Which of the following describes the 'conceptual' level in the three-schema architecture? A) It details how data is physically stored on disk, including file organizations and indexes. B) It defines the overall logical structure of the database for the entire organization. C) It provides a customized view of the data for a specific user or application. D) It manages the security and access permissions of all users. Show Answer Correct Answer: B) It defines the overall logical structure of the database for the entire organization. 26. How does the JOIN operation in relational algebra work? A) Concatenates two tables vertically. B) Combines rows from two tables based on a common attribute. C) Creates a new table with only unique values. D) Removes unwanted columns from a table. Show Answer Correct Answer: B) Combines rows from two tables based on a common attribute. 27. In an ERD, what do 'attributes' describe about an entity? A) The unique identifier for the entity. B) The cardinality of its relationships. C) The relationships it has with other entities. D) The properties or characteristics of the entity. Show Answer Correct Answer: D) The properties or characteristics of the entity. 28. A SELECT command without a WHERE clause returns? A) All records from a table that match the previous WHERE clause. B) All the records from a table, or information about all the records. C) SELECT is invalid without a Where clause. D) Nothing. Show Answer Correct Answer: B) All the records from a table, or information about all the records. 29. What is the recommended practice for naming tables in a database? A) Tables should be named in singular form. B) Tables should be named in plural form. C) Tables should include numerals. D) Tables should use multiple words without linking. Show Answer Correct Answer: A) Tables should be named in singular form. 30. Which DBMS is known for its open-source flexibility and is widely used by Wikipedia? A) PostgreSQL. B) Oracle Database. C) MySQL. D) MariaDB. Show Answer Correct Answer: D) MariaDB. 31. Which of the following is a result of reduced data dependence and reduced structural dependence? A) Increased structural dependence. B) Increased data redundancy. C) Reduced program maintenance. D) Decreased data sharing. Show Answer Correct Answer: C) Reduced program maintenance. 32. What is the primary purpose of database transaction isolation? A) To speed up data processing. B) To prevent data loss. C) To reduce database complexity. D) To ensure transactions do not interfere with each other. Show Answer Correct Answer: D) To ensure transactions do not interfere with each other. 33. What are the main types of DBMS? A) Graph, Time-series, Spatial. B) In-memory, Distributed, Columnar. C) Hierarchical, Network, Relational, Object-oriented, NoSQL. D) Flat-file, Key-value, Document-oriented. Show Answer Correct Answer: C) Hierarchical, Network, Relational, Object-oriented, NoSQL. 34. What will be the output of the following SQL query? SELECT COUNT (*) FROM Employees WHERE Salary > 50000; A) The number of employees earning more than 50, 000. B) The number of employees in the Employees table. C) The maximum salary in the Employees table. D) The total salary of employees earning more than 50, 000. Show Answer Correct Answer: A) The number of employees earning more than 50, 000. 35. Which of the following is not an Schema? A) Database Schema. B) Logical Schema. C) Physical Schema. D) Critical Schema. Show Answer Correct Answer: D) Critical Schema. 36. What should you do to ensure that the requested records meet your needs? A) Check if the results are what you asked for. B) Save or print the records immediately. C) Add new search filters without looking at the results. D) Log out to keep the system secure. Show Answer Correct Answer: A) Check if the results are what you asked for. 37. How does a DBMS improve data accessibility and responsiveness? A) By requiring users to write their own query languages. B) By limiting the functionality available to end-users. C) By allowing end-users to ask ad hoc questions and obtain information quickly. D) By providing a view mechanism to simplify data. Show Answer Correct Answer: C) By allowing end-users to ask ad hoc questions and obtain information quickly. 38. In a supertype/subtype hierarchy, each subtype has: A) At least one subtype. B) Only one supertype. C) Many supertypes. D) At most two supertypes. Show Answer Correct Answer: B) Only one supertype. 39. Which statement is true about the following diagram? A) A person can only be a faculty, student, or staff. B) A student can be both an undergraduate and a graduate student at the same time. C) All attributes of person and student are inherited by undergraduate. D) All attributes of graduate are inherited by person. Show Answer Correct Answer: A) A person can only be a faculty, student, or staff. 40. Which layer of a DBMS interacts directly with the database storage? A) Logical layer. B) Application layer. C) Physical layer. D) View layer. Show Answer Correct Answer: C) Physical layer. 41. What is the role of a data model? A) To visualize data flow. B) To define data structure. C) To optimize queries. D) To manage database security. Show Answer Correct Answer: B) To define data structure. 42. Disk (Media) Failure:Failure that destroys data stored on ..... ? A) Printer. B) Disk. C) Keyboard. D) Monitor. Show Answer Correct Answer: B) Disk. 43. What is the purpose of key constraints in a relation? A) To enforce referential integrity. B) To allow NULL values. C) To identify tuples uniquely. D) To define attribute domains. Show Answer Correct Answer: C) To identify tuples uniquely. 44. What is the maximum number of users normally supported by a workgroup database? A) 100. B) 50. C) 30. D) 10. Show Answer Correct Answer: B) 50. 45. Generalization in an ER model is: A) A process of defining a superclass from multiple subclasses. B) Represented by an ellipse in an ER diagram. C) A process of defining a subclass from a superclass. D) Used to combine two entities into one. Show Answer Correct Answer: A) A process of defining a superclass from multiple subclasses. 46. Which mapping does the DBMS check to determine the corresponding internal structures? A) External/Internal mapping. B) Physical/Conceptual mapping. C) Conceptual/Internal mapping. D) External/Conceptual mapping. Show Answer Correct Answer: C) Conceptual/Internal mapping. 47. Among OSI layers, which one provides user interfaces and support for services such as electronic mail, remote file access and transfer? A) Presentation layer. B) Transport layer. C) Application layer. D) Session layer. Show Answer Correct Answer: C) Application layer. 48. What are indexes and why are they important in databases? A) Indexes are data structures that enhance the speed of data retrieval in databases. B) Indexes are used to store images in databases. C) Indexes are methods for data backup in databases. D) Indexes are tools for data encryption in databases. Show Answer Correct Answer: A) Indexes are data structures that enhance the speed of data retrieval in databases. 49. Which of the following best describes relational databases? A) Data stored in hierarchical order. B) Data stored in flat text files. C) Data stored in tables with rows and columns linked by relationships. D) Data stored as images and videos. Show Answer Correct Answer: C) Data stored in tables with rows and columns linked by relationships. 50. What is the homework task for the database lesson? A) Design a new database system. B) Research and write about a database you didn't know before, including its name, purpose, users, and importance. C) Create a Google Form to collect data. D) Compare database systems with manual systems. Show Answer Correct Answer: B) Research and write about a database you didn't know before, including its name, purpose, users, and importance. 51. Explain the concept of normalization in database design. A) Normalization is the process of combining all data into a single table. B) Normalization eliminates the need for any relationships between tables. C) Normalization involves structuring a database to minimize redundancy and dependency by dividing data into related tables. D) Normalization is only concerned with increasing data storage capacity. Show Answer Correct Answer: C) Normalization involves structuring a database to minimize redundancy and dependency by dividing data into related tables. 52. Packaged data models: A) Are ready to use right out of the box. B) Require customization. C) Allow partial specialization. D) Cannot be used for most applications. Show Answer Correct Answer: B) Require customization. 53. ..... :Collecting only necessary data. A) Data Minimization. B) Data Expansion. C) Data Duplication. D) Data Sharing. Show Answer Correct Answer: A) Data Minimization. 54. Which of the following is an example of a database in daily life? A) A music playlist. B) A school's attendance system. C) A calculator. D) A digital clock. Show Answer Correct Answer: B) A school's attendance system. 55. What is data modeling? A) The analysis and definition of data structures required in a database. B) The process of creating a database. C) The process of encrypting data. D) The process of compressing data. Show Answer Correct Answer: A) The analysis and definition of data structures required in a database. 56. What does the 'C' in ACID represent? A) Integrity. B) Clarity. C) Consistency. D) Durability. Show Answer Correct Answer: C) Consistency. 57. What does the DISTINCT keyword do in SQL? A) Sorts the results. B) Groups records. C) Removes duplicate records. D) Filters records. Show Answer Correct Answer: C) Removes duplicate records. 58. Which of the following is a common use case for NoSQL databases? A) Maintaining strict data integrity. B) Performing complex joins. C) Handling large volumes of unstructured data. D) Storing structured financial data. Show Answer Correct Answer: C) Handling large volumes of unstructured data. 59. Why File Based System become unpopular? A) It causes sync with all the data synchronization. B) It causes data redundancy. C) All the above. D) None of the above. Show Answer Correct Answer: B) It causes data redundancy. 60. Which of the following is a characteristic of a distributed database? A) It requires constant internet connection. B) It does not support modular growth. C) It provides local flexibility and customization. D) It can only be accessed from a central server. Show Answer Correct Answer: C) It provides local flexibility and customization. ← PreviousNext →Related QuizzesScience QuizzesClass 12 QuizzesClass 12 Computer Science Chapter 3 Database Management Systems Quiz 1Class 12 Computer Science Chapter 3 Database Management Systems Quiz 2Class 12 Computer Science Chapter 3 Database Management Systems Quiz 3Class 12 Computer Science Chapter 3 Database Management Systems Quiz 4Class 12 Computer Science Chapter 3 Database Management Systems Quiz 5Class 12 Computer Science Chapter 3 Database Management Systems Quiz 6Class 12 Computer Science Chapter 3 Database Management Systems Quiz 7Class 12 Computer Science Chapter 3 Database Management Systems Quiz 8 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books