Entity Relationship Diagram (ER- Diagram)


Introduction

ER-Diagram is represents graphical representation of entities and relationship between them. ER-Diagram is really important for understanding flow of data within system.

Entity: An Entity is a business object which is represents a group of data.

ATTRIBUTE : An Attribute is a Sub-group of information/data within Entity.

Type of Entity Relationship:
  • Many-to-Many Relationship
  • One-to-Many Relationship
  • One-to-One Relationship

SYMBOLS

Entity1.gif

EXAMPLE : ER-DIAGRAM 

Entity2.gif