Question

Name foreign keys in table ATTENDANCE and STUDENT. Is there any foreign key in table GUARDIAN.

ATTENDANCE

Attribute Name	Data expected to be stored	Data Type	Constraint
RollNumber	Numeric value consisting of maximum 3 digits	INT	PRIMARY KEY
SName	Variant length string of maximum 20 characters	VARCHAR(20)	NOT NULL
SDateofBirth	Date value	DATE	NOT NULL
GUID	Numeric value consisting of 12 digits	CHAR(12)	FOREIGN KEY

STUDENT

Attribute Name	Data expected to be stored	Data Type	Constraint
GUID	Numeric value consisting of 12 digit Aadhaar number	CHAR(12)	PRIMARY KEY
GName	Variant length string of maximum 20 characters	VARCHAR(20)	NOT NULL
GPhone	Numeric value consisting of 10 digits	CHAR(10)	NULL UNIQUE
GAddress	Variant length string of size 30 characters	VARCHAR(30)	NOT NULL

GUARDIAN

Attribute Name	Data expected to be stored	Data Type	Constraint
AttendanceDate	Date value	DATE	PRIMARY KEY*
RollNumber	Numeric value consisting of maximum 3 digits	INT	PRIMARY KEY*, FOREIGN KEY
AttendanceStatus	‘P’ for present and ‘A’ for absent	CHAR(1)	NOT NULL

Answer 1

• STUDENT table: GUID is a Foreign Key. It refers to GUID in the GUARDIAN table.
• ATTENDANCE table: RollNumber is a Foreign Key. It refers to RollNumber in the STUDENT table.
• GUARDIAN table: There is no Foreign Key. GUID is its Primary Key.

Table	Foreign Key	References
STUDENT	GUID	GUARDIAN(GUID)
ATTENDANCE	RollNumber	STUDENT(RollNumber)
GUARDIAN	None	,

The foreign key in STUDENT is GUID, and the foreign key in ATTENDANCE is RollNumber. There is no foreign key in the GUARDIAN table.