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Ð High Cost: The cost of implementing a DBMS system is very high. It is also a very time-consuming process that involves analysing
user requirements, designing the database specifications, writing application programs, and then also providing training.
Ð Security and Recovery Overheads: Unauthorized access to a database can lead to a threat to the individual or organization
depending on the data stored. Also, the data must be regularly backed up to prevent its loss due to fire, earthquakes, etc.
4. What is MySQL?
Ans. MySQL is one of the most popular database management system software used for managing the relational database. It is
an open-source RDBMS software that is available free of cost. It can run on all operating systems, including Linux, Unix and
Windows. It is popular for web-based applications and online publishing. It uses a query language called SQL (Structured
Query Language). SQL is the standard language for managing relational databases and performing various operations on the
data in the tables. It would enable us to store, retrieve, and manipulate data in the form of tables.
5. What is Alter Table command? Write it`s syntax.
Ans. In Structured Query Language, the ALTER TABLE statement allows you to add, modify, and delete columns from an existing
table. This statement also allows database administrators to add and remove SQL constraints from existing tables.
Syntax:
ALTER TABLE table_name
ADD column name datatype;
6. The following commands are giving errors. Write the correct MYSQL commands. [CBSE Sample Paper 2023]
(a) alter table student delete marks;
(b) select * from employee where name =‘%s%’;
Ans. Alter table student drop marks;
select* from employee where name like ‘%s%’;
7. What is Alter Table command? Write it`s syntax. [CBSE Sample Paper 2023]
Ans. UPDATE Teacher
SET NAME =”AMITA”
WHERE NAME=”AMIT”;
8. i. Give any two characteristics of a relational model. [CBSE Sample Paper 2023]
ii. Which aggregate function is used to find the average of all the values for a selected attribute of a table?
Ans. In relational model,
i. A column is called an Attribute.
ii. The value in each tuple is an atomic value.
9. Ms Prabha has mistakenly entered ‘‘AMIT’’ instead of ‘‘AMITA’’ in name field of table ‘TEACHER’. Help her to write the correct
SQL command to make the desired changes in the table.
Ans. UPDATE Teacher
SET NAME =”AMITA”
WHERE NAME=”AMIT”;
C. Competency-based/Application-based question: Critical thinking
Rani has created a table of marks scored by her five friends in annual examination. Now, she wants to sort the students
according to the ascending order of their marks. Help her in doing so.
Ans. She should use ORDER BY command to do so.
Unsolved Exercise
Section A
(Objective Type Questions)
A. Choose the correct option.
1. The term DBA stands for ............................ .
i. Data Bank Administrator ii. Database Administrator
iii. Data Administrator iv. None of these
Database Concepts—RDBMS Tool 183

