exercise dadd

                                                                        QUESTION 1

a) What is the definition of relational key and why it is needed?

Definition: A key consists of one or more attributes that can be identified in a row. Relational key  is an attribute that relates one identify with another entity in a relationship.

 Why needed : Relational key enable us to link the tables together in a database for easier data access storage.

2. List and explain 4 types of relational keys.

         i.                               i.)            Candidate key

                   ii.)            Primay key

                  iii)             Foreign key

                 iv)           Composite key

3.Based on the table given below, answer all the following questions:
BORROWER:  Table

BORROWER ID	BORROWER NAME	CONTACT NO	ADDRESS	CATEGORY	AGE	DATE OF BIRTH
01-200506-003	Ali Ahmad	03-12345678	Sentral	Student	18	02-februari
01-200506-012	Aminah Hassan	03-45725575	Bandar Baru Bangi	Student	20	15-februari

   a)      What is the name for the above table? Borrower

b)      What is the primary key for the above table? Borrower ID

c)       What is data type for borrower’s name, category, age and data of birth colums? Text,text,number,date/time

d)      How many attribute and records contains in the table? 6

e)      What is the function of field size,input mask, and default solve?

                                                                      QUESTION 2

Based on the following diagram below, draw a complete entity relationship diagram (ERD) which includes entity,attributes, relationship, cardinality constraints and key attributes.

     Report On Retail Details

Owner no: 40612

Owner name: Fatimah Abd Rahman

HOUSE CODE	ADDRESS	RENTAL RATE	TORANT CODE	TENANT NAME	START DATE	END  DATE
H0021	Sentul	RM 560	T0621	Ali	01//10/04	30/09/05
H0022	Kajang	RM 660	T0022	Aminah	01/12/04	30/11/05
H0023	Bangi	RM 850	T0623	Stephen	01/01/04	31/12/04

Attibute:                                                         

Owner _no (PK)                                       

Owner_name                                                   

                                                                       

House code (PK)

Address

Rental_Rate

Torant code (PK)

 Terant_name

 Start_ Date

 End_ date
 ENTITY:-

• owner
• house
• tenant

 

                                                                        QUESTION 3

Every day, there are five doctor is on duty in orthopaedic words. There are working on shift and doctor can give a treatment to their patient and each patient can received a treatment from many doctor based on type of diseases. A patient can take a medicine but much medicine could be taken by many patients.

         i.                                 i)            Doctor information is DoctorID and Doctor Name

                   ii)            Patient information is PatientID, patient name, and address

                  iii)            Medicine information is medicineCode and medicine name.

                 iv)            For each treatment, it had TypeofTreatment and CostofTreatment

                   v)            For each accepted medicine, it has a Quantity and date