This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Computer Science > Class 12 Computer Science Chapter 3 Database Management Systems – Quiz 18 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Computer Science Chapter 3 Database Management Systems Quiz 18 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. In a LIKE clause, you can ask for any 6 letter value by writing A) LIKE .{6}. B) LIKE (that's six underscore characters). C) LIKE??????. D) LIKE (that's six dots). Show Answer Correct Answer: B) LIKE (that's six underscore characters). 2. What does the term 'metadata' refer to? A) Data that is no longer used. B) Data about data. C) Data stored in a database. D) Data that is encrypted. Show Answer Correct Answer: B) Data about data. 3. What is the difference between INNER JOIN and OUTER JOIN? A) INNER JOIN can include NULL values from both tables. B) INNER JOIN returns matched rows; OUTER JOIN returns all rows from one table with matched rows from the other. C) INNER JOIN returns all rows from both tables. D) OUTER JOIN only returns unmatched rows from both tables. Show Answer Correct Answer: B) INNER JOIN returns matched rows; OUTER JOIN returns all rows from one table with matched rows from the other. 4. How do you represent an ER diagram? A) Entities as rectangles, attributes as ovals, relationships as diamonds, connected by lines. B) Entities as circles, attributes as squares, relationships as triangles, connected by arrows. C) Entities as ovals, attributes as diamonds, relationships as rectangles, connected by dots. D) Entities as lines, attributes as stars, relationships as hexagons, connected by curves. Show Answer Correct Answer: A) Entities as rectangles, attributes as ovals, relationships as diamonds, connected by lines. 5. What is vertical partitioning? A) Distributing rows of a relation among different sites. B) Storing all data in a single location. C) Distributing columns of a relation among different sites. D) Creating multiple copies of the entire database. Show Answer Correct Answer: C) Distributing columns of a relation among different sites. 6. The ..... rule specifies that each entity instance of the supertype must be a member of some subtype in the relationship. A) Total convergence. B) Partial specialization. C) Total specialization. D) Semi-specialization. Show Answer Correct Answer: C) Total specialization. 7. What is the primary purpose of data normalisation? A) Increasing data redundancy. B) Reducing data redundancy and improving integrity. C) Speeding up database processing. D) Enhancing data security. Show Answer Correct Answer: B) Reducing data redundancy and improving integrity. 8. The process of defining one or more subtypes of a supertype and forming relationships is called: A) Selecting classes. B) Specialization. C) Generalization. D) Creating discord. Show Answer Correct Answer: B) Specialization. 9. How does a DBMS address the issue of data dependency? A) By compressing the data. B) By encrypting the data. C) By storing data in separate linked tables. D) By storing data in a single file. Show Answer Correct Answer: C) By storing data in separate linked tables. 10. How can a distributed database improve query performance? A) By processing queries closer to the location of the data. B) By storing all data on a single central server. C) By using weaker consistency models. D) By increasing data redundancy. Show Answer Correct Answer: A) By processing queries closer to the location of the data. 11. A member of a subtype does NOT necessarily have to be a member of the supertype. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 12. Why is it important for student information needed for course registration, accounting, and grade calculation to be consolidated into one standard database? A) It increases the number of databases required. B) It allows all applications to access consistent and accurate data. C) It makes data less secure. D) It reduces the need for software updates. Show Answer Correct Answer: B) It allows all applications to access consistent and accurate data. 13. GUI act as front end and database server act as ..... A) Container. B) Back End. C) End. D) None of the above. Show Answer Correct Answer: B) Back End. 14. Give an example of a real-world application of a database. A) Social media platform. B) Video streaming service. C) Online retail management system. D) Weather forecasting system. Show Answer Correct Answer: C) Online retail management system. 15. What is logical data independence? A) Changing the physical schema without affecting logical schemas. B) The ability to access data without knowing its structure. C) Changing the logical schema without affecting external schemas. D) The ability to enforce data integrity. Show Answer Correct Answer: C) Changing the logical schema without affecting external schemas. 16. What is a challenge related to the performance of a DBMS? A) Increased speed of data retrieval. B) Slower execution for specific tasks. C) Efficient handling of concurrent access. D) Optimal performance for all applications. Show Answer Correct Answer: B) Slower execution for specific tasks. 17. What is the cardinality ratio for a binary relationship where a faculty may counsel many students? A) 1:m. B) M:1. C) M:m. D) 1:1. Show Answer Correct Answer: A) 1:m. 18. How do you remove a table from a database in SQL? A) REMOVE TABLE. B) DELETE TABLE. C) DROP TABLE. D) CLEAR TABLE. Show Answer Correct Answer: C) DROP TABLE. 19. How does a DBMS improve data security? A) By implementing access rights and encryption. B) By deleting old data records automatically. C) By preventing all users from modifying data. D) By removing primary keys from tables. Show Answer Correct Answer: A) By implementing access rights and encryption. 20. What is required for converting a strong entity set with only simple attributes into a relational model? A) One table with attributes of the entity set. B) Two tables with primary keys. C) A composite attribute table. D) A multi-valued attribute table. Show Answer Correct Answer: A) One table with attributes of the entity set. 21. What are mapping constraints in an ER model? A) Mapping constraints specify the number of instances of one entity that can be associated with instances of another entity in an ER model. B) Mapping constraints determine the color and size of entities in a diagram. C) Mapping constraints are used to create relationships between tables in SQL. D) Mapping constraints define the attributes of an entity. Show Answer Correct Answer: A) Mapping constraints specify the number of instances of one entity that can be associated with instances of another entity in an ER model. 22. While practicing object oriented programming using Java, the execution of every Java program is under the control of: A) Java applet. B) Java Virtual class (JVC). C) Java Virtual Machine (JVM). D) Java application. Show Answer Correct Answer: C) Java Virtual Machine (JVM). 23. Describe the concept of foreign keys in relational databases. A) Foreign keys are used to link tables in relational databases, ensuring data integrity and establishing relationships between them. B) Foreign keys are used to store large amounts of data in a single table. C) Foreign keys are primarily for indexing data to improve query performance. D) Foreign keys are a type of data type used in programming languages. Show Answer Correct Answer: A) Foreign keys are used to link tables in relational databases, ensuring data integrity and establishing relationships between them. 24. What is the main benefit of using a database management system in healthcare? A) Allows manual entry of patient data. B) Provides a structured way to store and retrieve patient information efficiently. C) Automatically diagnoses patients without human intervention. D) Replaces the need for healthcare professionals. Show Answer Correct Answer: B) Provides a structured way to store and retrieve patient information efficiently. 25. Given a table students with columns student ..... id, name, and major, which SQL query lists all students majoring in 'Computer Science'? A) SELECT name FROM students WHERE major = 'Computer Science';. B) SELECT * FROM students WHERE major = 'Computer Science';. C) SELECT student id FROM students WHERE major = 'Computer Science';. D) SELECT student id, name FROM students WHERE major = 'Computer Science';. Show Answer Correct Answer: D) SELECT student id, name FROM students WHERE major = 'Computer Science';. 26. Define the term 'table' in the context of a database. A) A table is a graphical representation of data without any structure. B) A table is a structured collection of data in rows and columns in a database. C) A table is a single row of data in a database. D) A table is a type of software used for managing databases. Show Answer Correct Answer: B) A table is a structured collection of data in rows and columns in a database. 27. Which of the following is an advantage of the database approach? A) Increased program maintenance. B) Reduced structural dependence. C) Increased data redundancy. D) Limited data sharing. Show Answer Correct Answer: B) Reduced structural dependence. 28. What is the main advantage of using a NoSQL database? A) Relational data structure. B) Strict data consistency. C) Scalability and flexibility. D) Support for complex transactions. Show Answer Correct Answer: C) Scalability and flexibility. 29. MongoDB is an example of a relational database. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 30. What type of join includes all tuples from both participating relations? A) Left Outer Join. B) Inner Join. C) Right Outer Join. D) Full Outer Join. Show Answer Correct Answer: D) Full Outer Join. 31. ..... :Manages data policies and standards. A) Database User. B) System Analyst. C) Data Administrator (DA). D) Network Administrator. Show Answer Correct Answer: C) Data Administrator (DA). 32. ..... :Storing copies of data at multiple sites. A) Data Compression. B) Data Fragmentation. C) Data Encryption. D) Data Replication. Show Answer Correct Answer: D) Data Replication. 33. What do backups and replication protect against? A) File format changes. B) User errors. C) Data loss. D) Server upgrades. Show Answer Correct Answer: C) Data loss. 34. Which type of database is mentioned under "Database Architectures & Major Types of Databases" ? A) Quantum Databases. B) Operational Databases. C) Relational Algebra. D) Blockchain Databases. Show Answer Correct Answer: B) Operational Databases. 35. What does normalization help to improve? A) Data integrity. B) Data confusion. C) Data duplication. D) Data color. Show Answer Correct Answer: A) Data integrity. 36. What is the primary purpose of key constraints in relational databases? A) To ensure only valid data is entered into tables. B) To increase processing speed. C) To link tables together. D) To duplicate data for backup purposes. Show Answer Correct Answer: A) To ensure only valid data is entered into tables. 37. How can foreign keys help maintain data integrity? A) Foreign keys allow duplicate entries in a table. B) Foreign keys help maintain data integrity by ensuring that relationships between tables are valid and that referenced data exists. C) Foreign keys are only relevant for primary keys in a single table. D) Foreign keys can be used to delete all data in a database. Show Answer Correct Answer: B) Foreign keys help maintain data integrity by ensuring that relationships between tables are valid and that referenced data exists. 38. What kind of data does Netflix's database primarily manage? A) Financial transactions. B) User preferences for recommendations. C) School attendance data. D) Hospital records. Show Answer Correct Answer: B) User preferences for recommendations. 39. In ordered indices the file containing the records is sequentially ordered, a ..... is an index whose search key also defines the sequential order of the file. A) Unstructured index. B) Clustered index. C) Nonclustered index. D) Structured index. Show Answer Correct Answer: B) Clustered index. 40. What is Big Data? A) Data that is always accurate. B) Data that is easy to manage. C) A collection of data that is too large and complex for traditional systems. D) Data that is only stored in one location. Show Answer Correct Answer: C) A collection of data that is too large and complex for traditional systems. 41. What is the result of a set difference operation? A) No records. B) All records combined. C) Records in both relations. D) Records in one relation only. Show Answer Correct Answer: D) Records in one relation only. 42. The attribute refers to a ..... of a table A) Record. B) Field. C) Foreign key. D) Primary key. Show Answer Correct Answer: B) Field. 43. What is a major disadvantage of a file-based system compared to a DBMS? A) Data redundancy and inconsistency. B) Easier access control. C) Faster data retrieval. D) Better concurrency handling. Show Answer Correct Answer: A) Data redundancy and inconsistency. 44. CREATE TABLE employee (name VARCHAR, id INTEGER)What type of statement is this? A) DDL. B) TCL. C) DML. D) DCL. Show Answer Correct Answer: A) DDL. 45. What is the main focus of a database designer? A) Designing the database structure. B) Writing application code. C) Managing user access. D) Performing data entry. Show Answer Correct Answer: A) Designing the database structure. 46. What is the primary role of a Data Manipulation Language (DML) in a database? A) Defining database structure. B) Manipulating and querying database. C) Ensuring data security. D) Managing user permissions. Show Answer Correct Answer: B) Manipulating and querying database. 47. Which of the following would NOT use big data analysis? A) Public agencies. B) Healthcare companies. C) Retail companies. D) High school students doing homework. Show Answer Correct Answer: D) High school students doing homework. 48. What is a flat file? A) A file with multiple tables. B) A file with videos. C) A file with no relations. D) A file with images. Show Answer Correct Answer: C) A file with no relations. 49. What is the primary goal of data storage in a database system? A) Maximize data entry speed. B) Minimize query performance. C) Maximize data security. D) Minimize data redundancy. Show Answer Correct Answer: D) Minimize data redundancy. 50. What is the core part of an operating system that directly interacts with hardware? A) Kernel. B) Shell. C) GUI. D) API. Show Answer Correct Answer: A) Kernel. 51. What does the term 'aggregation' mean in ER modeling? A) Grouping attributes. B) Creating new entities. C) Linking relationships. D) Combining data. Show Answer Correct Answer: D) Combining data. 52. Which of the following is a use of DBMS in agriculture? A) Monitoring crop growth and yields. B) Predicting pest infestation trends. C) Managing irrigation schedules. D) All of the above. Show Answer Correct Answer: D) All of the above. 53. What is an access right in a DBMS? A) A permission level assigned to users or groups. B) A function that deletes old records. C) A setting that forces users to use SQL. D) A tool that automatically modifies database schemas. Show Answer Correct Answer: A) A permission level assigned to users or groups. 54. How can query execution plans help in optimizing SQL queries? A) They automatically rewrite SQL queries for better performance. B) Query execution plans help in optimizing SQL queries by revealing inefficiencies and guiding improvements. C) They provide a graphical representation of the database schema. D) They eliminate the need for indexing in databases. Show Answer Correct Answer: B) Query execution plans help in optimizing SQL queries by revealing inefficiencies and guiding improvements. 55. What is a rollback in transaction management? A) A rollback is a technique to create new transactions. B) A rollback is a process that undoes changes made during a transaction. C) A rollback is a process that saves changes made during a transaction. D) A rollback is a method to permanently apply changes in a database. Show Answer Correct Answer: B) A rollback is a process that undoes changes made during a transaction. 56. Define ACID properties in transaction management. A) Accuracy, Clarity, Integrity, Reliability. B) ACID properties:Atomicity, Consistency, Isolation, Durability. C) Atomicity, Concurrency, Isolation, Durability. D) Atomicity, Consistency, Isolation, Validity. Show Answer Correct Answer: B) ACID properties:Atomicity, Consistency, Isolation, Durability. 57. A lock that allows concurrent transactions to access different rows of the same table is known as a A) Table-level lock. B) Row-level lock. C) Page-level lock. D) Database-level lock. Show Answer Correct Answer: B) Row-level lock. 58. What is the benefit of using NoSQL databases? A) NoSQL databases are less efficient than traditional SQL databases. B) NoSQL databases are only suitable for small datasets. C) NoSQL databases require a fixed schema for data storage. D) The benefit of using NoSQL databases includes flexibility, scalability, and the ability to handle large volumes of unstructured data. Show Answer Correct Answer: D) The benefit of using NoSQL databases includes flexibility, scalability, and the ability to handle large volumes of unstructured data. 59. What is the difference between a weak entity and a strong entity? A) A strong entity is always dependent on a weak entity for its existence. B) Both weak and strong entities have the same characteristics and can be used interchangeably. C) A weak entity depends on a strong entity for its existence and lacks a primary key, whereas a strong entity can exist independently and has a primary key. D) A weak entity has a primary key and can exist independently. Show Answer Correct Answer: C) A weak entity depends on a strong entity for its existence and lacks a primary key, whereas a strong entity can exist independently and has a primary key. 60. What is a key feature of a database? A) It cannot store multimedia data. B) It can only be accessed by one user. C) It is designed for a specific purpose. D) It is always small in size. Show Answer Correct Answer: C) It is designed for a specific purpose. ← 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