The document provides an overview of the Entity Relationship (ER) model, which is a conceptual data modeling technique for describing and visualizing entities and their relationships. The key aspects summarized are: - The ER model consists of entities, relationships between entities, and attributes that describe entities. Entities can be physical or conceptual objects. - Relationships associate entities and have mapping cardinalities like one-to-one, one-to-many, many-to-one, many-to-many. - Entities have attributes that can be simple/atomic, composite, single-valued, multi-valued, stored or derived. Primary keys uniquely identify entities.

1. Entity Relationship Model Presented By Swati Patil

7. Composite attributes forms a hierarchy for e.g address

24. Notations used for E-R diagram: