CBSE Guess > Papers > Important Questions > Class XII > 2010 > Computer Science > Computer Science By Ravi Kiran
CBSE CLASS XII
5. (a) Candidate Key: The attribute (Column) or set of attributes (Columns)
which can identify a tuple/row uniquely are known as Candidate Key(s).
Candidate Key: The attribute (Column) or set of attributes (Columns),
which are capable of acting as candidate for primary key.
Cardinality of a relation: Number of rows in a table form cardinality of a
relation.
(b) (i) SELECT W_ID,FIRSTNAME,ADDRESS,CITY FROM
WORKERS WHERE CITY='New York';
(ii) SELECT * FROM WORKERS ORDER BY LASTNAME;
(iii) SELECT FIRSTNAME, LASTNAME, SALARY+BENEFITS
FROM WORKERS.DESIG WHERE DESIGNATION=’CLERK’
AND WORKERS,W_ID=DESIG.W_ID;
OR
SELECT FIRSTNAME,LASTNAME,SALARY+BENEFITS AS
TOTAL SALARY FROM WORKERS.DESIG WHERE
DESIGNATION=’CLERK’ AND
WORKERS.W_ID=DESIG.W_ID;
(iv) SELECT MIN(SALARY), DESIGNATION FROM DESIG WHERE
DESIGNATION IN ('Manager'.'Clerk') GROUP BY DESIGNATION;
OR
SELECT MIN(SALARY), DESIGNATION FROM DESIG WHERE
DESIGNATION= ‘Manager’ OR DESIGNATION='Clerk' GROUP BY
DESIGNATION;
OR
SELECT MIN(SALARY) FROM DESIG WHERE DESIGNATION=‘Manager’ OR DESIGNATION='Clerk';
OR
SELECT MIN(SALARY) FROM DESIG WHERE DESIGNATION IN
(‘Manager’,‘Clerk’);
(v) Sam 75000
Manila 70000
George 75000
(vii) Director 85000
Salesman 60000
6. (a) Absorption Law:
X+X.Y=X
OR
X.(X+Y)=X
OR
X+X’.Y=X+Y
OR
X.(X’+Y)=X.Y
X Y X.Y X+X.Y
0 0 0 0
0 1 0 0
1 0 0 1
1 1 1 1
OR
X Y X+Y X.(X+Y)
0 0 0 0
0 1 1 0
1 0 1 1
1 1 1 1
OR
X Y X’ X’+Y X.(X’+Y) X.Y
0 0 1 0 0 0
0 1 1 1 0 0
1 0 0 0 0 0
1 1 0 1 1 1
OR
X Y X’ X’.Y X+X’.Y X+Y
0 0 1 0 0 0
0 1 1 1 1 1
1 0 0 0 1 1
1 1 0 0 1 1
Paper By Mr. Ravi Kiran
Email Id : [email protected]
