Short note on E-R diagram (Entity Relationship Diagram).
E-R diagram (Entity Relationship Diagram) :-
The overall logical structure of a data base can be expressed graphically by an ER diagram which consist of the following components.
1. Rectangles , which represent entity sets.
2. Ellipses, which represent attributes.
3. Diamonds, which represent relationship among entity set.
4. Lines, which link attributes to entity set and entity sets to relationship.
E-R diagram for a part of the database of a project management systems.
Some symbols used in E-R diagram
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