1. ERD (Entity Relationship Diagrams)By
Kustanto
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2. E-R Diagrams E-R Diagram is a design methodology for modeling the
Entities
Relationships
using a diagram with specified shapes for entities, relationships, roles of entities in these relationships, and cardinality.
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3. Entity
“An entity is a business object that represents a group, or category of data.”
A entity is a object or event which needs to be tracked
Example: Car, student, departement, instructor, employee, etc.
Symbol:
Entity
Employee
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4. Attribute An attribute is a sub-group of information within an entity.
Characterize entity sets
Example: Id, name, address, religion, gender
Symbol:
Employee Id
Name
address
Religion
Gender
Attribute
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5. Relationship
Specify the relations among entities from two or more entity sets
Symbol:
Example:
Relationship
Assigned To
Employee
Project
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6. Symbol ERD Cardinality: ENTITY One Relationships
One or Many Relationships
Zero or One Relationships
Attribute
Zero or Many Relationships
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7. Cardinality Relation One to Many Table B Table A A1 A2 A3 B2 B3
Relation one-to-one
Table A
Table l B A1 A2 A3 B1 B2 B3
Relation Many to Many
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8. Cardinality PROJECTS EMPLOYEE (a) Basic to relationship EMPLOYEE
Assigned to
PROJECTS
EMPLOYEE
(a) Basic to relationship
Assigned to
EMPLOYEE
PROJECTS
(b) Relationship with cardinality
Contoh:
Project 1
Amir
Project 2
Dewi
Project 3
Fahmi
Project 4
Sueb
Project 5
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9. Cardinality PATIENT VISIT (a) Basic to relationship PATIENT HISTORY
Has
PATIENT
VISIT
(a) Basic to relationship
Has
PATIENT
HISTORY
PATIENT
(b) Relationship with cardinality
Example:
Visit 1
Amir
Visit 2
Dewi
Visit 1
Fahmi
Visit 1
Visit 2
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10. Example: ERD Assigned To Projects Located No Name Employee Id Name
address
Religion
Gender
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11. ER Diagrams for Payroll
Phone
Name
Customer
CustID
Address
Has
Name
CustID
Projects
Description
ProjID
Total
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12. End of Sessions
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