DATABASE CONCEPTS WORKSHEET
1)Nisha is assigned the task of maintaining the staff data of an organization. She has to store the details of
the staff in the SQL table named EMPLOYEES with attributes as EMPNO, NAME, DEPARTMENT,
BASICSAL to store Employee’s Identification Number, Name, Department, and Basic Salary respectively.
There can be two or more Employees with the same name in the organization.Help Nisha to identify the
attribute which should be designated as the PRIMARY KEY .Justify your answer. (BOARD 25)
2)If a table which has one Primary key and two alternate keys. How many Candidate keys will this table
have? (SP 24-25)
a)1 b) 2 c) 3 d) 4
3)Which of the following statements is FALSE about keys in a relational database? (SP 23-24)
a)Any candidate key is eligible to become a primary key.
b)A primary key uniquely identifies the tuples in a relation
c)A candidate key that is not a primary key is a foreign key.
d)A foreign key is an attribute whose value is derived from the primary key of another relation
4)Fill in the blank: (SP 22-23)
_____________ is a non -key attribute , whose values are derived from the primary key of some other
table.
a)Primary Key b)Foreign Key c)Candidate Key d)Alternate Key
5)Fill in the blank :(Board 23)
___________ is a number of tuples in a relation,
a)attribute b)degree c)domain d)cardinality
6)The school has asked their estate manager Mr. Rahul to maintain the data of all the labs in a table LAB,
Rahul has created a table and entered data of 5 labs.
LABNO LAB_NAME INCHARGE CAPACITY FLOOR
L001 CHEMISTRY Daisy 20 I
L002 BIOLOGY Venky 20 II
L003 MATH Preeti 15 I
L004 LANGUAGE Daisy 36 III
L005 COMPUTER Mary Kom 37 II
Based on the data given above answer the following questions:
i)Identify the columns which can be considered as Candidate keys
ii)Write the degree and cardinality of the table.
7) (SP 20-21)
1
1)Nisha is assigned the task of maintaining the staff data of an organization. She has to store the details of
the staff in the SQL table named EMPLOYEES with attributes as EMPNO, NAME, DEPARTMENT,
BASICSAL to store Employee’s Identification Number, Name, Department, and Basic Salary respectively.
There can be two or more Employees with the same name in the organization.Help Nisha to identify the
attribute which should be designated as the PRIMARY KEY .Justify your answer. (BOARD 25)
2)If a table which has one Primary key and two alternate keys. How many Candidate keys will this table
have? (SP 24-25)
a)1 b) 2 c) 3 d) 4
3)Which of the following statements is FALSE about keys in a relational database? (SP 23-24)
a)Any candidate key is eligible to become a primary key.
b)A primary key uniquely identifies the tuples in a relation
c)A candidate key that is not a primary key is a foreign key.
d)A foreign key is an attribute whose value is derived from the primary key of another relation
4)Fill in the blank: (SP 22-23)
_____________ is a non -key attribute , whose values are derived from the primary key of some other
table.
a)Primary Key b)Foreign Key c)Candidate Key d)Alternate Key
5)Fill in the blank :(Board 23)
___________ is a number of tuples in a relation,
a)attribute b)degree c)domain d)cardinality
6)The school has asked their estate manager Mr. Rahul to maintain the data of all the labs in a table LAB,
Rahul has created a table and entered data of 5 labs.
LABNO LAB_NAME INCHARGE CAPACITY FLOOR
L001 CHEMISTRY Daisy 20 I
L002 BIOLOGY Venky 20 II
L003 MATH Preeti 15 I
L004 LANGUAGE Daisy 36 III
L005 COMPUTER Mary Kom 37 II
Based on the data given above answer the following questions:
i)Identify the columns which can be considered as Candidate keys
ii)Write the degree and cardinality of the table.
7) (SP 20-21)
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