Question

Consider the following tables PATIENT and TEST and answer the questions that follow :

PCODE	NAME	PHONE	DTADMIT	TESTID
6473	Amit Sharma	912356899	19 - JUN - 2017	T102
7134	Rose Mathew	886744536	12 - NOV - 2017	T101
8786	Tina Sharma Arora	889088765	06 - DEC - 2017	T102
6477	Vijay Shah	714567445	07 - DEC - 2017	T502
7658	Venkat Fazal	865545343	31 - DEC - 2017	T101

Note : 

• NAME holds the Names of patients. 
• DTADMIT holds dates on which a patient was admitted to hospital. 
• TESTID holds Ids of Medical tests done on patients.

TESTID	TESTNAME	COST
T101	Platelet Count	200.00
T102	Hemogram	190.00
T301	Malaria Detection	350.00
T502	Glucose test	150.00

Name the Primary keys in both the tables and foreign key in ‘PATIENT’ table. State the reason for your choice.

Answer 1

Primary key in PATIENT and TEST tables are PCODE and TESTID respectively. Because primary key of a relational table uniquely identifies each record. 

Foreign key in PATIENT table is TESTID whose value is derived from the primary key (TESTID) of another table (TEST).