LU03c - ERM and ERD

The Entity-Relationship Model (ERM) is a conceptual data-model used in database design to represent relationships between data entities in a system. An entity is a real-world object or concept, such as customer or product, and each entity has specific attributes that describe it. ERM serves as a blueprint for creating databases, ensuring that data is accurately captured and linked. The following illustration shows a database of students, their teachers and the rooms in which the lessons are are held.

An Entity-Relationship Diagram (ERD) is the graphical representation of the ERM, visualizing entities, attributes, and their relationships. Commonly using Crow's Foot notation, ERDs clarify the structure of the database before development begins, making them essential for communicating design, ensuring normalization, and preventing errors. Below is an ERD of a school administration database.

• ER-Modell - Teil 1
• ER-Modell - Teil 2

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