A categorization of data models

Note that all of the following are Data Models.

1. An Entity Relationship Diagram (ERD) only shows entities and relationships between entities. It is the simplest logical model.
   
2. A Key-Based Model shows the entities, their primary keys, alternate keys, foreign keys and the relationships between entities. It is the intermediate logical model.
   
3. A Fully Attributed Model shows entities, keys, non-key attributes and the relationships between entities. It is the final logical model.
   
4. A Physical Model converts entities to tables, attributes to columns and applies the constraints of the host RDBMS to the Logical Model.
   
5. The Database Schema is the implementation of the Physical Model on the host RDBMS.