Class-XII, UNIT - 1: DATABASE CONCEPTS (Part-1), IT skills-802, CBSE

 

UNIT - 1: DATABASE CONCEPTS (Part-1)

QUESTION ANSWERS

 

Important Q/ ANS strictly as per the CBSE syllabus for class-XII  _____________        

INFORMATION TECHNOLOGY-802                                                                                

 

Q1: Define Data and Information.

Data is a collection of raw facts and figures. It is unprocessed and unorganized, and it does not have any inherent meaning.

Information is data that has been processed, organized, and interpreted. It has meaning and can be used to make decisions or solve problems.

Q2: Difference between data and information.

DATA	INFORMATION
1.      Raw facts and figures	1.      Processed, organized, and interpreted data
2.      No inherent meaning	2.      Has meaning and can be used to make decisions or solve problems
3.      Unorganized form	3.      Organized form
4.      Not typically useful on its own need to process	4.      Useful for making decisions or solving problems
5.      E.g. Marks obtained by students in an examination	5.      E.g. Result or Performance of the class

 

Q3. Define Database?

A database is an organized collection of structured information, or data. It is also called as Single Repository.

 A database is usually controlled by a database management system (DBMS).

 

Q4. Mention the properties of Database?

A database has the following properties:

1.      A database is a representation of some aspect of the real world also called miniworld.

2.      It is designed, built and populated with data for specific purpose.

3.      It can be of any size and complexity.

4.      It can be maintained manually or it may be computerized.

 

 Q5. Mention the USES or Advantages of Database?

1. Accuracy: The data in a database should be accurate and up-to-date.
2. Completeness: The database should contain all of the data that is needed for its intended purpose.
3. Consistency: The data in the database should be consistent with itself.
4. Integrity: The data in the database should be protected from unauthorized access and modification.
5. Reliability: The database should be reliable and available when needed.
6. Security: The database should be secure and protected from unauthorized access and modification.
7. Usability: The database should be easy to use and understand.

Q6. Mention the disadvantages of databases?

1. Databases can be expensive to implement and maintain.
2. The cost of hardware, software, and staffing.
3. Databases can be complex to design, implement, and manage.
4. Databases can be slow to query and update, especially for large databases.
5. Security and Recovery Overheads

 

Q7. Why there is a need of databases?

1. Databases are designed to store and manage large amounts of data efficiently.
2. Databases provide a structured way to store data, which makes it easy to access and manage.
3. To ensure data accuracy and integrity.
4. To protect the data, it provides the features such as user authentication, data encryption, and access control.
5. Databases can be used to store and manage data.

Q8. Define DBMS?

A database management system is a collection of programs that enables users to create, maintain and use a database.

Some examples of DBMS are – MySQL, Oracle, DB2, IMS, IDS etc.

Q9. Mention the common operations that are performed on a database.

Operations that are commonly performed on a database are as follows:

1.    Defining the Database

2.    Populating the Database

3.    Manipulating the Database means modifying the database, retrieving data or querying the database.

4.    Sharing the Database

5.    Protecting the Database from software/ hardware failures and unauthorized access.

6.    Maintaining the Database.

Q10. What are the main Characteristics of Database Management Systems?

1.    Self-describing Nature of a Database System

2.    Insulation Between Programs and Data this property is called Program-Data Independence.

3.    Sharing of Data, it means that it allows multiple users to access the database simultaneously.

4.    ACID properties: Dbms support ACID (Atomicity, Consistency, Isolation, Durability) 

5.    Data mining: It is the process of extracting knowledge from large amounts of data.

6.    Backup and recovery features to protect data from loss or damage.

7.    Provide a number of features to protect data from unauthorized access and corruption. 

Q11 How many types of users of DBMS?

1.    End Users: Users who use the database for querying, modifying and generating reports as per their needs.

2.    Database Administrator (DBA): DBA administers the database and the DBMS. The DBA is responsible for authoring access, monitoring its use, providing technical support, acquiring software and hardware resources.

3.    Application Programmers: Application programmes write application programs in high level languages and SQL to interact with the database.

4.    System Analyst: System analyst determines the requirements of the end users and then develops specifications to meet these requirements.

Q12. What is the Role of DBA in DBMS?

1.    Database Administrator (DBA)

2.    The DBA administers the database and the DBMS.

3.    The DBA is responsible for authoring access, monitoring its use, providing technical support, acquiring software and hardware resources.

4.    responsible for managing and maintaining DBMSs.

  

Q13.Write some real-world applications of DBMS?

1. DBMSs are used by banks, to store and manage customer account information, transaction history, and other financial data.
2. DBMSs are used by hospitals to store and manage patient records, medical history, test results, and billing information.
3. DBMSs are used by schools and colleges to store and manage student records, course schedules, and grades.
4. DBMSs are used by government agencies to store and manage census data, tax records, and other public information
5. DBMS are used by e-commerce websites to store and manage product information, customer orders, and shipping details.
6. DBMSs are used by social media platforms to store and manage user profiles, posts, and other content.

Q14. What are the advantages and disadvantages of DBMS?

Advantages

1.       Reduction in Redundancy

2.       Improved Consistency.

3.       Improved Availability

4.       Improved Security

5.    User Friendly:

Disadvantages

1.       The cost of implementing a DBMS system is very high.

2.       Security and Recovery Overheads

3.       Unauthorized access to a database can lead to threat

4.    Also, the data must be regularly backed up to prevent its loss due to fire, earthquakes, etc.

Q15. Name two domains where database management may be used.

Government, Hospital, Education, banking etc.

 

 Q16. List the various ways in which database management applications can be used in Government Sector.

1.       For storing details of tax records like sales tax, house tax etc.

2.       Store and manage census data

3.       Maintaining criminal records

4.       To store details of PAN cards, AADHAR cards

5.       Vehicle registration

6.       Birth/death certificate registration

7.       Mid-day meal Record

8.       Widow Pension

Q17. Relational database developed by ______________in 1970.

a)      E.F Codd at IBM

b)      E.F Codd Hp

c)       E.F Codd at Intel

d)    F.F Codd at IBM

Q18. Define RDBMS.

A relational database management system (RDBMS) is a type of database management system (DBMS) that stores data in tables. Tables are made up of rows and columns.

1.       A row is called a Tuple.

2.       A column is called an Attribute.

3.       A table is called as a Relation.

4.       The number of attributes in a relation is called the Degree of a relation.

5.       The number of rows in a relation is called the Cardinality of a relation.

6.    Relation Schema R is denoted by R (A, A …, A) where R is the relation name 1 2 3, n and A, A …. A is the list of attributes.

Q19. If the value of an attribute in a tuple is not known or not applicable or not available, a special value called _____________

a)    Null

b)      Not Applicable

c)      Nil

d)      None of these

 

Q20. Write any two examples of RDBMS.

Examples of RDBMS are Oracle, MySQL, IBM DB2.

Q21. Define Constraint. With example.

Constraints, are restrictions on the values, stored in a database based on the requirements. Example, in the relation EMPLOYEE:

1.       the Employee_ID must be a 4-digit number,

2.    the Age must be greater than 18

Q22.  List the various types of constraints in Relational model.

Various types of constraints in Relational model are as follows:

1.      DOMAIN CONSTRAINT: It specifies that the value of every attribute in each tuple must be from the domain of that attribute. For example, the Employee_ID must be a 4-digit number.

2.   KEY CONSTRAINT: It specifies that value be according to the Rules of key that is applied. For example, Aadhar number is the primary key it cannot be left null.

3.      NULL VALUE CONSTRAINT: Attributes/value cannot be left unfilled or vacant.

4.    ENTITY INTEGRITY CONSTRAINT: This constraint specifies that primary key of a relation cannot have null value.

5.     REFERENTIAL INTEGRITY CONSTRAINT: This constraint ensures that the consistency of data between two or more tables.

Practice Questions

Q1: What is the REFERENTIAL INTEGRITY CONSTRAINT explain with example?

Ans: A referential integrity constraint is a database constraint that ensures the consistency of data between two or more tables.

For example, consider a database with two tables: Customers and Orders. The Customers table has a primary key column called customer_id. The Orders table has a foreign key column called customer_id that references the primary key column in the Customers table. This RIC ensures that every order in the Orders table is associated with a valid customer in the Customers table.

Q2: ________________is a collection of raw facts, which have not been processed to reveal useful information.

Ans: Data

Q3. Write the name of any two DBMS.

Ans: MySQL, Oracle, DB2, IMS, and IDS etc.

 

Q4. Why there is a need /requirement of Database?

Ans: 1. Databases are designed to store and manage large amounts of data efficiently.

2. To protect the data, it also provides the features such as user authentication, data encryption, and access control.

 

Q5. Difference between data and information.

Ans: Difference between data and information:

Data is a collection of raw facts and figures. It is unprocessed and unorganized, and it does not have any inherent meaning.

Information is data that has been processed, organized, and interpreted. It has meaning and can be used to make decisions or solve problems.

 

Q6. Define the following

1)      Database

2)      Database management system

 A database is an organized collection of structured information, or data. It is also called as Single Repository.

 A database is usually controlled by a database management system (DBMS).