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TOPIC 2 : ENTITY RELATIONSHIP MODEL
2.1 Understand Entity Relationship Model (E-R)
Disember 2012
Section A : Question 4
Explain the main component of the following entity relationship
model
1. Entities
2. Attributes
(4 marks)
Disember 2012
Section B : Question 2 (a)
Define the term primary key.
(2 marks)
Disember 2012
Section A : Question 5
With the aid of a diagram, draw an appropriate ER based on the
following scenario.
1. A company operates four departments
2. Each department employs employees
(4 marks)
Disember 2012
Section B : Question 2 (b)
With the aid of a diagram, sketch and describe clearly the
following ER Model
1. 1 : 1 (One to one)
2. 1 : M (one to many)
3. M : N (Many to many)
(9 marks)
Disember 2013
Section A : Question 3
Figure below is the ER model of a Product. Produce the data for
the product in:
1. Model scheme
2. Model instance
(4 marks)
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Disember 2013
Section A : Question 4
State the purpose of the E-R model and how it helps in the
designing of databases.
(4 marks)
Disember 2013
Section A : Question 5
Draw an E-R diagram for each of the following statements:
a. The Machines are made up of parts. Attribute of the parts
include PartID and PartName.
b. A publisher publishes several books. Attribute of the books
include ISBN and Author.
(4 marks)
Disember 2012
Section B : Question 2 (b)
Draw the ER model and state the cardinality for every scenario
below:
1. Painter can paint many paintings, each painting is painted by
one painter.
(3 marks)
2. An employee can learn many skills, each skill can be learned
by many employees.
(3 marks)
3. An employee manages one store, each store is managed by one
employee.
(3 marks)
Jun 2013
Section A : Question 4
Patients are treated in a single ward by the doctors assigned to
them. Usually each patient will be
assigned a single doctor, but in rare cases they will have two.
Healthcare assistants also attend to the
patients, a number of these are associated with each ward
From the statement above, identify the entity and the
relationship between all the entity.
(4 marks)
Jun 2013
Section A : Question 5
Draw an ER diagram with attributes and entities for the
following:
Customer identified by a CUSTOMER_NAME and with an address buy
items, items are identified by an
ITEM_NO an have a COLOR. The QTYBOUGHT of an item by each
customer is recorded. An item can be
bought by many customers.
(4 marks)
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Jun 2013
Section B : Question 2
The company you work wants to digitize their time cards. You
have been asked to design the database
for submitting and approving time cards. With the following
information:
. A timecard should have hours worked and date submitted
. Each timecard is associated with exactly one employee
. Each timecard should have a unique id
. Each timecard has a status: it is either approved, not
approved, or pending
. Each employee has a unique id
. Each employee has a name and address.
. Each employee submits a time card every pay period. i.e. In I
year, they will submit multiple time cards
. Each employee either has direct deposit or physical check as
their method of payment
. Each employee is associated with exactly one manager
. Each manager has a unique id and a name
. Each manager is in charge of multiple employees
. Each manager approves timecards for multiple employees
Based on the above statements,
(a) Identify the entities and their attributes
[8 marks]
(b) Draw all the relationship between entities.
[3 marks]
(c) Draw the complete Entity Relationship (ER) diagram.
[9 marks]
