Sample Paper – 2012
Class – XII
Subject – Informatics Practices

Q1 Answer the following questions:

(a) Compare Char and Varchar datatype of SQL.

(b) Prerna needs to remove all the rows from SALE_HISTORY table to release the storage space. But she does not want to remove the table structure. Which statement should she use?

(c) Meena uses a STUDENT table with following columns:
NAME ,CLASS,COURSE_ID,COURSE_NAME
She needs to display names of students who have not been assigned any course or have been assigned “pathology” course. Pathology course’s names end with “Pathology”. She wrote the following query:
SELECT NAME,CLASS
FROM STUDENT,COURSE
WHERE COURSE_NAME = NULL OR COURSE_NAME = “%pathology”;But the query is not producing result. Identify the problem.

(d) What is the importance of primary key in a table? Explain with example.