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SAD/U4 Topic 2 Entity Relationship Diagrams

The ER or (Entity Relational Model) is a high-level conceptual data model diagram. Entity-Relation model is based on the notion of real-world entities and the relationship between them.

ER modeling helps you to analyze data requirements systematically to produce a well-designed database. So, it is considered a best practice to complete ER modeling before implementing your database.

Entity relationship diagram displays the relationships of entity set stored in a database. In other words, we can say that ER diagrams help you to explain the logical structure of databases. At first look, an ER diagram looks very similar to the flowchart. However, ER Diagram includes many specialized symbols, and its meanings make this model unique.

Sample ER Diagram

2.1 ERDiagram.png

Facts about ER Diagram Model:

  • ER model allows you to draw Database Design
  • It is an easy to use graphical tool for modeling data
  • Widely used in Database Design
  • It is a GUI representation of the logical structure of a Database
  • It helps you to identifies the entities which exist in a system and the relationships between those entities

Why use ER Diagrams?

Here, are prime reasons for using the ER Diagram

  • Helps you to define terms related to entity relationship modeling
  • Provide a preview of how all your tables should connect, what fields are going to be on each table
  • Helps to describe entities, attributes, relationships
  • ER diagrams are translatable into relational tables which allows you to build databases quickly
  • ER diagrams can be used by database designers as a blueprint for implementing data in specific software applications
  • The database designer gains a better understanding of the information to be contained in the database with the help of ERP diagram
  • ERD is allowed you to communicate with the logical structure of the database to users

Components of the ER Diagram

This model is based on three basic concepts:

  • Entities
  • Attributes
  • Relationships
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