Summary Database Management System - Relation model and Relational database

Module-3

Relational Model and
Relational Algebra

, What is Data Model
• A way to show structure of database

• Data models define how the logical structure of a
database is modeled.

• Data Model is a fundamental entity to introduce
abstraction in a DBMS.

• Data models define how data is connected to each other
and how they are processed and stored inside the system.

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, Data models
1. Hierarchical Data Model

2. Network Data Model

3. ER Data Model

4. Relational Data Model

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, Hierarchical Model
• Organize data items into structures that look like trees,
• Items of data at higher levels exist over items that are a
level lower.
• Items that are related exist on the same level.




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