1. ROYAL UNIVERSITY OF PHNOM PENH
 Depart : Computer Science
 Subject : Software Engineering
 Class : E2, Year4
 Batch : 13
 Lecturer : KEAN TAK
 Pre Topic : Entity Relationship and Diagram
Group1
1. Ben Piseth 7. Chea Sokhom
2. Chan Kimchhun 8. Chea Sakall
3. Chan Sopov 9. Chin puttra
4. Chanthy Raksmey 10.Chhim Vichhai
5. Chao Yokchivve 11.Choun Piseth
7. Chev Toun 1

2. Group 1
WHAT IS ERD?
• Is a diagram used to conduct data
modeling activity.
• It describes the relationship between data
object.
• DBA and System Analyst used ERD to
perform data modeling, and explain the
diagram to stakeholders.
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3. Group 1
ERD COMPONENTS
• The primary components of ERD are:
• Data object
• Attribute
• Relationship
3

4. Group 1
ERD COMPONENTS
Association
between the
instances of one or
more entity types
Data Object Relationship Attributes
Person, place, object, event named property or
or concept about which data characteristic of an
is to be maintained entity
Represents a set or collection of
objects in the real world that
share the same properties
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5. Group 1
CARDINALITY
• express the minimum and maximum
number of occurrences of one entity
for a single occurrence of the other
• One-to-One (1:1)
• One-to-many (1:N)
• Many-to-Many (M:N)
5

6. Group 1
RELATIONSHIP CARDINALITY
Graphic Cardinality
Exactly 1
0 or 1
1 or more
0 or many
More than 1
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7. Group 1
DEGREE OF RELATIONSHIP
• Refer to the number of Entity type that
participate in the relationship.
• There are three case:
• Unary: between two instances of one entity type
• Binary: between the instances of two entity
types
• Ternary: among the instances of three entity
types
7

8. Group 1
EXAMPLE OF ERD
8

9. Group 1
BENEFIT OF ERD
• Visual representation :
• Effective communication
• Simple to understand
• High flexibility
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10. Group 1, Section 4.4
THE END
Thanks for your enjoying.
Good Luck !!!
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