Maharashtra Board Class 11 Information Technology Chapter 2 Introduction to DBMS Solutions

Complete the Following Activity

 

Question 1. Tick whichever box is not valid.

 

Question 1. Complete the following concept map for Data type.
Answer:
Data type:

• Graphic
• Data
• Number
• Text

This classification helps in organizing different forms of information systematically.
In simple words: A data type tells the computer what kind of value a field can hold, such as text, numbers, or dates.

🎯 Exam Tip: Make sure to memorize the basic data types like Text, Number, and Date as they are frequently asked in classification questions.

 

Question 2. The student wants to create a field Pincode in a table, which data type he will choose?
Answer: Int. Since a pincode consists entirely of numerical digits, using an integer data type is the most efficient choice for storage and validation.
In simple words: Since a pincode is made of numbers, we use the 'Int' (integer) data type to store it.

🎯 Exam Tip: Always choose 'Int' or 'Integer' for fields that contain only whole numbers without any letters or special characters.

 

Question 3. Tick the appropriate box.
Primary key:

• is also called foreign key
• Uniquely identifies a record

Answer: Uniquely identifies a record. A primary key ensures that no two rows in a database table have the exact same identifier, maintaining data integrity.
In simple words: A primary key is like a student's roll number; it is unique for everyone and helps find their specific information instantly.

🎯 Exam Tip: Remember that a primary key must always contain unique values and cannot contain NULL values.

 

Question 4. Tick the appropriate circle.
Database has:
• Only one record
• Only single table
• One or many tables
• None of the options
Answer: One or many tables
In simple words: A database is designed to hold one or multiple tables so that different types of related information can be stored and organized neatly.

🎯 Exam Tip: Remember that databases are highly scalable and almost always contain multiple tables to avoid repeating data.

2. Observe the field names of a database given below in ‘Column A’ related to Bus reservation. Write suitable data types for each field in front of the respective field in ‘Column B’.

 

Question 1.
Answer:

Column A (Field Name)	Column B (Data Type)
Passenger Name	Varchar
Age	Int
Gender	Char
Mobile Number	Int

In simple words: We use different data types for different kinds of information: 'Varchar' for text like names, 'Char' for single letters like gender (M/F), and 'Int' for whole numbers like age and phone numbers.

🎯 Exam Tip: Always match the data type to the nature of the data; use Varchar for text of variable length and Int for numeric values that don't have decimals.

3. Write the use of the following SQL command.

 

Question 1. Match the SQL commands with their correct uses:
(i) INSERT
(ii) UPDATE

Answer:
• INSERT: Insert data into a table
• UPDATE: Updates data in a table
In simple words: INSERT is used to add new rows of information to a table, while UPDATE is used to modify existing information already stored in the table.

🎯 Exam Tip: Remember that INSERT adds brand new records, whereas UPDATE changes records that are already there.

4. Create a Table for the Information Given Below by Choosing Appropriate Data Types. Specify Proper Primary Key for the Table (1) Movie (2) Actor

 

Question 1. Movie (Registeration_no, movie_name, Realease_Date)
Answer: CREATE TABLE Movie (Registeration_no int(20) PRIMARY KEY, movie_name VARCHAR(20), Realease_Date DATE); This SQL statement defines the structure of the Movie table with appropriate data types and constraints.
In simple words: This command creates a table named 'Movie' where 'Registeration_no' is a unique number identifying each movie, 'movie_name' holds text, and 'Realease_Date' holds the date.

🎯 Exam Tip: Always specify the PRIMARY KEY constraint on the column that uniquely identifies each record, and choose appropriate data types like INT, VARCHAR, and DATE.

 

Question 2. Actor (actor_id, Actor_name, birth_date )
Answer: CREATE TABLE Actor (actor_id int(20) PRIMARY KEY, Actor_name VARCHAR(20), Birth_Date DATE); The query ensures that every actor has a unique identifier through the primary key constraint.
In simple words: This command creates a table named 'Actor' with a unique ID for each actor, a text field for their name, and a date field for their birthday.

🎯 Exam Tip: Ensure there are no spaces in column names and use underscores like 'actor_id' to keep the syntax clean and error-free.

5. Consider the Following Table Stationary. Write SQL Commands for the Following Statements.

Table: Stationary

S_ID	S_Name	C_Name	Price	Quantity
001	NoteBook	ABC	20	50
002	Pencil box	XYZ	10	80
003	A4Pages rim	PQR	600	2

 

Question 1. Write SQL command to create above Table.
Answer: CREATE TABLE Stationary (S_ID int(20) PRIMARY KEY, S_Name VARCHAR(20), C_Name VARCHAR(20), Price int(20), Quantity int(20)); This command establishes the structural schema of the table with appropriate data types for each field.
In simple words: This command creates a new table named Stationary with columns for ID, name, company name, price, and quantity.

🎯 Exam Tip: Always specify the PRIMARY KEY constraint on the unique identifier column (like S_ID) to ensure data integrity.

 

Question 2. Write SQL command to insert the above-mentioned record in the table.
Answer: INSERT INTO Stationary Values (001, 'Note Book', 'ABC', 20,50);
INSERT INTO Stationary Values (002, 'Note Book', 'XYZ', 10,80);
INSERT INTO Stationary Values (003, 'Note Book', 'PQR', 600,02); These statements successfully populate the table with the initial dataset.
In simple words: These commands add the rows of information about the stationary items into our newly created table.

🎯 Exam Tip: Make sure the values in the INSERT statement match the order and data types of the columns defined in the CREATE TABLE command.

 

Question 3. To delete the above table.
Answer: DROP TABLE Stationery; This command permanently removes the table structure and all its data from the database.
In simple words: This command completely deletes the table and all the information stored inside it.

🎯 Exam Tip: Remember that DROP deletes the entire table structure, whereas DELETE only removes the rows inside it.

6. Answer the Following Questions.

 

Question 1. What is a database?
Answer: A DBMS is a collection of programs (computer-based system) that enables the user to create and maintain a database it is used to define, construct and manipulate the data in the database for various applications. It provides information storage, retrieval, and security features to manage large volumes of data efficiently.
In simple words: A database is like a digital filing cabinet that helps us store, organize, and find information very quickly.

🎯 Exam Tip: Define both database and DBMS clearly, highlighting key functions like storing, retrieving, and managing data to score full marks.

 

Question 2. What are the advantages of a DBMS?
Answer: Advantages of a DBMS:
1. Redundancy is controlled: In File Processing System, duplicate data is created in many places because all the programs have their own files. This creates data redundancy which in turn wastes labor and space. In Database Management System, all the files are integrated into a single database. The whole data is stored only once in a single place so there is no chance of duplicate data. This centralized approach ensures that data remains consistent across all departments.
2. Sharing of Data: In a database, the users of the database can share the data among themselves. There are various levels of authorization to access the data. And consequently, the data can only be shared based on the correct authorization protocols being followed.
3. Data Security: Data Security is a vital concept in a database. Only authorized users should be allowed to access the database and their identity should be authenticated using a username and password. Unauthorized users should not be allowed to access the database under any circumstances as it violates the integrity constraints.
4. Enforces integrity constraints: Constraints are used to store accurate data because there are many users who feed data in the database. Data stored in the database should always be correct and accurate. DBMS provides the capability to enforce these constraints on the database.
In simple words: A DBMS helps store data in one central place so there is no duplicate information. It also makes it easy to share data safely with authorized people while keeping it secure from others.

🎯 Exam Tip: To score full marks, list at least four key advantages like controlling redundancy and data security, and briefly explain each with relevant keywords.

 

Question 3. What do you understand by Data Model?
Answer: A Database model defines the logical design and structure of a database and defines how data will be stored, accessed, and updated in a database management system. While the Relational Model is the most widely used database model.

Relational Model:
It is the most popular data model in DBMS. The relational model is the primary data model, which is widely used for data processing. This model has all properties required to process data with storage efficiency, making it highly reliable for modern applications.
In simple words: A data model is like a blueprint for a database. It decides how information is organized, stored, and connected so that users can find it easily.

🎯 Exam Tip: Always mention the Relational Model as the most common example when defining data models to show a practical understanding.

 

Question 4. What is a primary key?
Answer: Primary Key: A column in the table that uniquely identifies each row in that table is called a primary key. It ensures that no two records in a table are identical, maintaining data integrity.
In simple words: A primary key is like a student roll number or an ID card. It is a unique code that helps us identify a specific row in a table without any confusion.

🎯 Exam Tip: Remember that a primary key cannot contain NULL values and must always be unique for every row.

 

Question 5. What is DDL (Data Definition Language)
Answer: DDL statements or commands are used to define and modify the database structure of your tables or schema. When you execute a DDL statement, it takes effect immediately. Some examples of DDL commands are CREATE, ALTER, and DROP. These commands help in setting up the initial framework of the database.
In simple words: DDL is a set of commands used to build or change the structure of a database, like creating a new table or deleting an old one.

🎯 Exam Tip: Clearly list CREATE, ALTER, and DROP as key examples of DDL commands to secure full marks.

 

7. In a Company the Data is Stored in a Table Under the Following Fields Employee Number, Last Name, Date of Birth, Address. Which Data Type Will You Use for the Above Field?

 

Question 1. Identify the appropriate data types for the fields in the company table:

• Employee Name
• last name
• Address
• Date of birth

Answer:

Field Name	Data Type
Employee Name	Char
Last Name	Char
Address	Varchar
Date of Birth	Date

In simple words: This table shows the correct data types for each field in a database, where names use character types, addresses use variable characters, and birth dates use the date format.

🎯 Exam Tip: Always choose 'Varchar' for fields like Address where the length of the text can vary significantly, and 'Char' for fixed-length text fields.

8. Multiple Choice Select Three Correct Answers

 

Question 1. Valid relationships in RDBMS are
(a) one to one
(b) one to two
(c) one to many
(d) many to two
(e) many to many
(f) one to three
Answer: (a) one to one, (c) one to many, (e) many to many
In simple words: In a relational database, tables can be linked in three standard ways: one-to-one, one-to-many, or many-to-many, which helps organize how data connects.

🎯 Exam Tip: Remember that RDBMS only supports three standard relationship types: one-to-one, one-to-many, and many-to-many. Other options like 'one-to-two' are invalid.

Complete the Following

 

Question 1. Complete the following table:
Answer:

Use	Command
To remove access rights or privileges from the database	Revoke
Extracts data from a table	Insert into Select

In simple words: This table matches database tasks with their correct SQL commands, such as using Revoke to take away user permissions.

🎯 Exam Tip: Be sure to clearly distinguish between DDL, DML, and DCL commands like Revoke to score full marks in database questions.