EntitätRelationsModelle

EntitätRelationsModelle, often abbreviated as ER-Modelle, are conceptual data models used in database design. They represent the structure of data by illustrating entities, their attributes, and the relationships between them. An entity is a real-world object or concept that can be uniquely identified, such as a customer, a product, or an order. Attributes are the properties that describe an entity, like a customer's name, address, or email.

Relationships define how entities are associated with each other. These relationships can be one-to-one, one-to-many, or many-to-many, indicating the number of instances of one entity that can be related to instances of another entity. For example, a one-to-many relationship might exist between a customer and their orders, where one customer can place multiple orders, but each order belongs to only one customer.

ER-Modelle are typically visualized using Entity-Relationship Diagrams (ERDs). These diagrams use specific symbols to represent entities, attributes, and relationship types. ERDs serve as a blueprint for database administrators and developers, aiding in the clear communication of data requirements and facilitating the creation of efficient and well-structured databases. They are a fundamental tool in the database development lifecycle, bridging the gap between user requirements and the technical implementation of a database. The process of creating an ER-Modell involves identifying all relevant entities, defining their attributes, and establishing the connections between them based on business rules.