Entity
Relationship
Diagram
Presented by:
Muhammad umer
Bs(cs) 4th (b)

Entity relationship
diagram
* In 1976 Peter Chen was developed ERD
* Introduce by Charles Bachman
* A Graphical Representation
* A Semantic Data model

COMPONENTS OF ERD
* Data objects
* Data attributes
* Relationship

TYPES OF
RELATIONSHIP
* One to One
* One to Many
* Many to Many

ONE TO ONE
ROOF
COVERS
COVERD BY
BUILDING

ONE TO MANY
EMPLOYEE
WORK IN
HAS
DEPARTMENT

MANY TO MANY
EQUIPMENT
ALLOCATED TO
ALLOCATED
PROJECT

CARDINALITY & MODALITY
* Cardinality:
Express the maximum number of
relationships
* Modality:
Express whether the relationships is
optional or mandatory

THANK
YOU