Entity-Relationship (ER) Model
An Entity-Relationship (ER) model is a conceptual and visual representation used in database design to describe the interrelated entities and their relationships within a specific domain of knowledge. The ER model is composed of entity types, which classify the things of interest, and specifies relationships that can exist between entities. It is typically represented graphically as boxes (entities) connected by lines (relationships) to express the associations and dependencies between entities.
Purpose and Components
The ER model is used to model real-world objects and their relationships, such as people, objects, or concepts, and to represent the overall logical structure of a database graphically. It helps in identifying entities to be represented in the database and how those entities are related. The major components of the ER model include entities, attributes, and relationships. Entities are represented as rectangles, attributes as ellipses, and relationships as diamonds in the ER diagram.
Importance and Application
ER diagrams are crucial in database design as they provide a standard solution for visualizing data logically and are used to model and design relational databases in terms of logic and business rules. They are also used as a communication tool understood by all stakeholders, both technical and non-technical users, to ensure that the database system meets the requirements of the users. Additionally, ER diagrams can be easily translated into relational tables, increasing user productivity.
In summary, the ER model is a fundamental tool in database design, providing a graphical approach to represent entities and their relationships, and is widely used to ensure that database systems meet the requirements of users.
https://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model https://www.geeksforgeeks.org/introduction-of-er-model/ https://www.lucidchart.com/pages/er-diagrams https://www.javatpoint.com/dbms-er-model-concept https://www.guru99.com/er-modeling.html
