ER MODELS
COMPONENT DESCRIPTION
Prepared by:Owais khan
,DEFINATION:
An entity–relationship model (ER model) is a systematic way of
describing and defining a business process. An ER model is typically
implemented as a database.
TERMINOLOGIES OF ER MODEL:
1) Entity
An entity can be a real-world object,that can be easily identifiable. For example, in a
school database, students, teachers, classes, and courses offered can be considered
as entities.represented by rectangles.
ENTITY
, 2) ATTRIBUTES:
Entities are represented by means of their properties, called attributes. All attributes have
values. For example, a student entity may have name, class, and age as attributes.
Types of Attributes
Simple attribute − Simple attributes are atomic values, which cannot be divided further. For
example, a NIC is an atomic value of 14 digits.
ATTRIBUTES
COMPONENT DESCRIPTION
Prepared by:Owais khan
,DEFINATION:
An entity–relationship model (ER model) is a systematic way of
describing and defining a business process. An ER model is typically
implemented as a database.
TERMINOLOGIES OF ER MODEL:
1) Entity
An entity can be a real-world object,that can be easily identifiable. For example, in a
school database, students, teachers, classes, and courses offered can be considered
as entities.represented by rectangles.
ENTITY
, 2) ATTRIBUTES:
Entities are represented by means of their properties, called attributes. All attributes have
values. For example, a student entity may have name, class, and age as attributes.
Types of Attributes
Simple attribute − Simple attributes are atomic values, which cannot be divided further. For
example, a NIC is an atomic value of 14 digits.
ATTRIBUTES
