erwin Data Modeler User Interface › The Data Modeling Workspace › Logical and Physical Modeling › The Logical Model

The Logical Model

The logical model is the version of the model that represents all of the logical business requirements of an organization. There are three levels of logical models that are used to capture these requirements:

• The Entity Relationship Diagram - A high-level data model that includes all major entities and relationships. The Entity Relationship Diagram does not contain much detail and is often used in the initial planning phase.
• The Key Based Model - A model that describes major data structures such as entities, primary keys, and sample attributes.
• The Fully Attributed Model - A complete model that includes all required entities, attributes, key groups, and relationships.

A logical model can be created in conjunction with the physical model, or independent of the physical model. Logical models can also be derived from other models using the Derive Model Wizard.

In addition, you can define model objects in a logical model as logical only, and in a physical model as physical only. These options allow for the logical model to be fully normalized and for the corresponding physical model to be denormalized.

More information:

How to Derive a Model