Understanding Entity-Relationship and Database Models
Entity Relationship Model
Features:
The model was proposed by Peter P. Chen and may be used as a basis for a unified view of the data, taking the natural approach in the real world that consists of entities and relationships.
The E/R model, as its name implies, focuses on two fundamental concepts: the entity and the relationship.
In the E/R models, we can distinguish key elements such as entities, attributes, and relationships, plus the set of values, analogous to the concept of dominance.
Advantages:
- Conceptual Simplicity: Given this structure, the relationship between levels is logically simple.
- Database Security: The database is provided and implemented by the DBMS, ensuring security runs evenly throughout the system.
- Data Independence: The DBMS creates an environment in which the independence of the data can substantially reduce programming effort and maintenance.
- Data Integrity: Given the relation