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Analysis and Design
E-R Data Modeling Technique
Now we know various data models available. To understand the process of data
modeling we'll study Entity Relationship model. Peter P. Chen originally proposed
the Entity- Relationship (ER) model in 1976. The ER model is a conceptual data
model that views the real world as a construct of entities and associations or
relationships between entities.
A basic component of the model is the Entity-Relationship diagram, which is
used to visually represent data objects. The ER modeling technique is frequently
used for the conceptual design of database applications and many database design
tools employ its concepts.
ER model is easy to understand. Moreover it maps easily to relational model.
The constructs used in ER model can easily be transformed into relational tables.
We will look into relational model in the next chapter, where other data models
are discussed. In the following section, we'll look at E-R model concepts.
We can compare ER diagram with a flowchart for programs. Flow chart is a tool
for designing a program; similarly ERD is a tool for designing databases. Also
an ER diagram shows the kind and organization of the data that will be stored
in the database in the same way a flowchart chose the way a program will run.
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