Question & Answer

Question 1

a) What is the defination of relational & why it is needed?
Relational key are device that relates one entity with another entity in relationship. A key consist of one or more attributes that can be identified in a row and enables us to link the table together in database for easier data access storage.

b) List and explain 4 type of relational keys.
i. Candidate Key
- an attribute or group of attribute that identify a unique row in a relation.
ii. Primary Key
- any of the candidates that are selected to be the key or an attribute that uniquely identifies each row in a relational table.
iii. Foreign Key
- an attribute in one table whose values must match the primary key in another table or whose value must not null.
iv. Composite Key
- a primary key that consists of more than one attribute, especially in (M:N) relationship.

c) Based on table given below, answer all the following question:

i) What is the name for the above table? BORROWER

ii)What is the primary key for above table?
BORROWER_ID

iii) What is data type for borrower's name, category, age and date of birth colum?

1. BORROWER NAME- text
2. CATOGERY- text
3. DATE OF BIRTH- date/time
4. AGE- number

iv) How many attributes and records contains in the table?

1. attributes- 7
2. records- 2

v) What is the function of field size, input mask and default value?

1. field size- the maximum number of character you can enter in the field.
2. input mask- a pattern for all data to be entered in this field.
3. defult value- a value that automatically entered in this field for new records. 

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