An ER Diagram (Entity-Relationship Diagram) is a graphical representation of an entity-relationship model, which is used to visualize the structure of a database.
Thank you for reading this post, don't forget to subscribe!- It shows the relationships between entities (data objects) and their attributes, and helps in designing the database schema by illustrating the logical structure of the data.
Key Components of ER Model:
1.) Entities:
Entities are objects or things in the real world that are distinguishable from other objects. Each entity has a set of attributes.
- Example: In a university database, entities could be Students, Professors, and Courses.
2.) Attributes:
Attributes are properties or characteristics of an entity.
- Example: For the Student entity, attributes might include StudentID, Name, and DateOfBirth.
3.) Relationships:
Relationships are associations among entities.
- Example: A Student entity might have a relationship with the Course entity, indicating which courses a student is enrolled in.
4.) Keys:
- Primary Key: A unique identifier for each entity instance.
- Foreign Key: An attribute that creates a link between two entities.
5.) ER Diagrams:
- A graphical representation of entities, attributes, and relationships.
Benefits of ER Model:
- Simplifies database design.
- Provides a clear view of the data structure.
- Helps identify entities and relationships.