Question 1

Question 2Assertion. Data redundancy may lead to data inconsistency.Reason. When redundant data or the multiple copies of data mismatch, it makes the data inconsistent.

Accepted Answer

(a)Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationData redundancy refers to the duplication of data in a database. This may lead to data inconsistency. When redundant data or the multiple copies of data mismatch, it makes the data inconsistent.

Question 2

Question 3Assertion. Data redundancy may lead to many problems.Reason. In RDBMS, data redundancy is 100% removed.

Accepted Answer

(c)Assertion is true but Reason is false.ExplanationData redundancy may lead to many problems. It refers to the duplication of data in a database, which can result in data inconsistencies, increased storage requirements, and difficulties in maintaining data integrity. In RDBMS, data redundancy is minimized but not completely eliminated.

Question 3

Question 6Assertion. There can be multiple options for choosing a primary key in a data table.Reason. All attribute combinations inside a data table that contain unique values for each row, are the candidate keys.

Accepted Answer

(a)Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationThere can be more than one attribute in a relation possessing the unique identification property. All attribute combinations inside a relation that can serve as a primary key are candidate keys, as they are candidates for the primary key position.

Question 4

Question 7Assertion. All types of keys contain unique values for each row.Reason. A foreign-key attribute of a table is the primary key of another table.

Accepted Answer

(d)Assertion is false but Reason is true.ExplanationNot all types of keys necessarily contain unique values for each row. While primary keys ensure uniqueness for each row in a table, other types of keys, such as foreign keys and candidate keys, may not guarantee uniqueness. A non-key attribute, whose values are derived from the primary key of some other table, is known as foreign key in its current table.

Question 5

Question 8Assertion. The foreign-keys of tables are used to establish relationships with other tables and must be handled carefully.Reason. Referential integrity is a system of rules that a DBMS uses to ensure that the relationships between tables remain valid and no accidental change or deletion occurs in the related data.

Accepted Answer

(a)Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationThe foreign keys of tables are utilized to establish relationships with other tables, while referential integrity is a system of rules that a DBMS employs to ensure the validity of relationships between records in related tables. This system prevents users from accidentally deleting or changing related data. Therefore, it is crucial to handle foreign keys carefully.

Question 6

Question 1Summarize the major differences between a relation and a traditional file.

Accepted Answer

Relation fileTraditional fileData organized in tables with rows and columns.Data stored in unstructured formats.Supports structured querying with SQL.Lacks standardized querying abilities.Allows for defining relationships between tables.No inherent support for relationships.Offers flexibility in data storage and retrieval.Limited flexibility in data organisation.Examples : MySQL, PostgreSQLExamples : Text files, CSV files, Excel spreadsheets

Question 7

Question 3What is data redundancy ? How does it impact a database ?

Accepted Answer

Duplication of data is known as data redundancy. Data redundancy in a database leads to wasted storage and multiple copies of the same data. When these copies do not match with one another, it leads to data inconsistency. Additionally, data redundancy can result in performance degradation, security risks, and increased complexity.

Question 8

Question 6(i)Define primary key.

Accepted Answer

A primary key is a set of one or more attributes that can uniquely identify tuples within the relation.

Source: This question is from Relational Databases, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Relational Databases: Question, Primary, Key, Relational Databases, Computer Science. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach This QuestionRead the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from Relational DatabasesQ1: Question 1 Summarize the major differences between a relation and a traditional file.
Q11: Question 3(ii) Define candidate key.
Q13: Question 6(ii) Define foreign key.
Q14: Question 7 What is MySQL ? What are its functions and features ?
Q15: Question 8 What is the role of database server in database management system ? Give the key...
Practice more questions from Relational Databases &mdash; Computer Science, Class 12 CBSE

Question 9

Question 6(ii)Define foreign key.

Accepted Answer

A non-key attribute, whose values are derived from the primary key of some other table, is known as foreign key in its current table.

Source: This question is from Relational Databases, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Relational Databases: Question, Foreign, Key, Relational Databases, Computer Science. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach This QuestionRead the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from Relational DatabasesQ1: Question 1 Summarize the major differences between a relation and a traditional file.
Q11: Question 3(ii) Define candidate key.
Q12: Question 6(i) Define primary key.
Q14: Question 7 What is MySQL ? What are its functions and features ?
Q15: Question 8 What is the role of database server in database management system ? Give the key...
Practice more questions from Relational Databases &mdash; Computer Science, Class 12 CBSE

Question 10

Question 7What is MySQL ? What are its functions and features ?

Accepted Answer

MySQL is a freely available open source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL). MySQL provides us with a rich set of features that support a secure environment for storing, maintaining and accessing data.The functions and features of MySQL are as follows :Speed — If the server hardware is optimal, MySQL runs very fast. It supports clustered servers for demanding applications.Ease of use — MySQL is a high performance, relatively simple database system. From the beginning, MySQL has typically been configured, monitored and managed from the command line. However, several MySQL graphical interfaces are also available.Query Language Support — MySQL understands standards based SQL.Portability — MySQL provides portability as it has been tested with a broad range of different compilers and can work on many different platforms. It is fully multi-threaded using kernel threads. It can easily use multiple CPUs if they are available.Cost — MySQL is available free of cost. MySQL is a open source database.Data Types — MySQL provides many data types to support different types of data. It also supports fixed-length and variable-length records.Security — MySQL offers a privilege and password system that is very flexible and secure, and that allows host-based verification. Passwords are secure because all password traffic is encrypted when we connect to a server.Scalability and Limits — MySQL can handle large databases. Some real life MySQL databases contain 50 million records, some have up to 60,000 tables and about 5,000,000,000 rows.Connectivity — Clients can connect to MySQL Server using several protocols.Localization — The server can provide error messages to clients in many languages.Clients and Tools — MySQL provides several client and utility programs. These include both command-line programs such as mysqldump and mysqladmin, and graphical programs such as MySQL Administrator and MySQL Query Browser. MySQL Server has built-in support for SQL statements to check, optimize and repair tables.

Question 11

Question 8What is the role of database server in database management system ? Give the key features of MySQL.

Accepted Answer

A database server is the key to solving the problems of database management system (information system). In general, a server must reliably manage a large amount of data in a multi-user environment so that many users can concurrently access the same data. A database server must also prevent unauthorized access and provide efficient solutions for failure recovery.The key features of MySQL are as follows :Speed — If the server hardware is optimal, MySQL runs very fast. It supports clustered servers for demanding applications.Ease of use — MySQL is a high performance, relatively simple database system. From the beginning, MySQL has typically been configured, monitored and managed from the command line. However, several MySQL graphical interfaces are also available.Query Language Support — MySQL understands standards based SQL.Portability — MySQL provides portability as it has been tested with a broad range of different compilers and can work on many different platforms. It is fully multi-threaded using kernel threads. It can easily use multiple CPUs if they are available.Cost — MySQL is available free of cost. MySQL is a open source database.Data Types — MySQL provides many data types to support different types of data. It also supports fixed-length and variable-length records.Security — MySQL offers a privilege and password system that is very flexible and secure, and that allows host-based verification. Passwords are secure because all password traffic is encrypted when we connect to a server.Scalability and Limits — MySQL can handle large databases. Some real life MySQL databases contain 50 million records, some have up to 60,000 tables and about 5,000,000,000 rows.Connectivity — Clients can connect to MySQL Server using several protocols.Localization — The server can provide error messages to clients in many languages.Clients and Tools — MySQL provides several client and utility programs. These include both command-line programs such as mysqldump and mysqladmin, and graphical programs such as MySQL Administrator and MySQL Query Browser. MySQL Server has built-in support for SQL statements to check, optimize and repair tables.

Question 12

Question 10How are SQL commands classified ?

Accepted Answer

SQL commands can be divided into the following categories :Data Definition Language (DDL) CommandsData Manipulation Language (DML) CommandsTransaction Control Language (TCL) CommandsSession Control CommandsSystem Control Commands

Question 13

Question 11What functions should be performed by ideal DDL ?

Accepted Answer

An ideal DDL should perform the following functions :It should identify the types of data division such as data item, segment, record and data-base file.It should give a unique name to each data-item-type, record-type, file-type, database and other data subdivision.It should specify the proper data types.It should specify how the record types are related to make structures.It may define the type of encoding the program uses in the data items (binary, character, bit, string etc.). This should not be confused with the encoding employed in physical representation.It may define the length of the data items.It may define the range of values that a data-item can assume.It may specify means of checking for errors in the data.It may specify privacy locks for preventing unauthorized reading or modification of the data.A logical data definition should not specify addressing, indexing or searching techniques or specify the placement of data on the storage units, because these topics are in the domain of physical, not logical, organization.

Question 14

Question 12Differentiate between DDL and DML commands.

Accepted Answer

Data Definition Language (DDL)Data Manipulation Language (DML)DDL provides a set of definitions to specify the storage structure and access methods used by the database system.DML is a language that enables users to access or manipulate data as organized by the appropriate data model.DDL commands are used to perform tasks such as creating, altering, and dropping schema objects. They are also used to grant and revoke privileges and roles, as well as for maintenance commands related to tables.DML commands are used to retrieve, insert, delete, modify data stored in the database.Examples of DDL commands are CREATE, ALTER, DROP, GRANT, ANALYZE etc.Examples of DML commands are INSERT, UPDATE, DELETE, SELECT etc.

Question 15

Question 13Name some commands used to assign/revoke privileges from database users.

Accepted Answer

Commands used to assign/revoke privileges from database users are GRANT, REVOKE.

Source: This question is from Relational Databases, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Relational Databases: Question, Commands, Assign, Revoke, Privileges, Database. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach This QuestionRead the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from Relational DatabasesQ1: Question 1 Summarize the major differences between a relation and a traditional file.
Q11: Question 3(ii) Define candidate key.
Q12: Question 6(i) Define primary key.
Q13: Question 6(ii) Define foreign key.
Q14: Question 7 What is MySQL ? What are its functions and features ?
Practice more questions from Relational Databases &mdash; Computer Science, Class 12 CBSE

Question 16

Question 14Name some table maintenance commands.

Accepted Answer

Table maintenance commands are ANALYZE TABLE, CHECK TABLE, REPAIR TABLE, RESTORE TABLE.

Source: This question is from Relational Databases, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Relational Databases: Question, Table, Maintenance, Commands, Relational Databases, Computer Science. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach This QuestionRead the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from Relational DatabasesQ1: Question 1 Summarize the major differences between a relation and a traditional file.
Q11: Question 3(ii) Define candidate key.
Q12: Question 6(i) Define primary key.
Q13: Question 6(ii) Define foreign key.
Q14: Question 7 What is MySQL ? What are its functions and features ?
Practice more questions from Relational Databases &mdash; Computer Science, Class 12 CBSE

Question 17

Question 15What is TCL part of SQL ?

Accepted Answer

TCL part of SQL includes commands for specifying the beginning and ending of transactions along with commands to have control over transaction processing. Some examples of TCL commands are COMMIT, ROLLBACK, SET TRANSACTION and SAVEPOINT. These commands manage changes made by DML commands.

Question 18

Question 2What are views ? How are they useful ?

Accepted Answer

A view is a (virtual) table that does not really exist in its own right but is instead derived from one or more underlying base tables. Views are useful to view desired information that is actually stored in a base table and they extend the control we have over our data. They are an excellent way to give people access to some but not all of the information in a table.

Question 19

Question 3(ii)Define candidate key.

Accepted Answer

All attribute combinations inside a relation that can serve as primary key are candidate keys as they are candidates for the primary key position.

Source: This question is from Relational Databases, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Relational Databases: Question, Candidate, Key, Relational Databases, Computer Science. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach This QuestionRead the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from Relational DatabasesQ1: Question 1 Summarize the major differences between a relation and a traditional file.
Q12: Question 6(i) Define primary key.
Q13: Question 6(ii) Define foreign key.
Q14: Question 7 What is MySQL ? What are its functions and features ?
Q15: Question 8 What is the role of database server in database management system ? Give the key...
Practice more questions from Relational Databases &mdash; Computer Science, Class 12 CBSE

Question 20

Question 6What do you understand by the terms Primary Key and Degree of a relation in relational database ?

Accepted Answer

A primary key is a set of one or more attributes that can uniquely identify tuples within the relation. The primary key is non-redundant, meaning it does not have duplicate values in the same relation, and non-null attribute, meaning a null value cannot be inserted into it.The number of attributes in a relation is called Degree of a relation. A relation having 3 attributes is said to be a relation of degree 3. Similarly, a relation having n attributes is said to be a relation of degree n.

Relational Databases

Assertions And Reasons

Assignments

Checkpoint 121

Multiple Choice Questions

Truefalse Questions