Models and SubModels
Database schema diagrams (models) can become very complex very quickly. In order to bring order to these very complex database schema diagrams, ER-Designer supports the concept of sub-models.
The screen snap shot at the right shows ER-Designers logical main-model and six sub-models. You can create, edit, and delete sub-models from Model Tree.
A sub-model is a limited visual presentation (don't want to use the word view here...) of a subset of the database schema presenting the tables, views, and relationships of interest to the DB Architect or app developer. The sub-model allows the architect or developer to focus on their particular point of interest in their system (database of application).
The two snap shots in Figure 2 show diagrams for the main logical model and one of the sub-models. The snap shot on the left is an over view of the entire database. As an overview, only the table names, the primary and foreign keys, and relationships are shown in the diagram. The diagram on the left is one of the sub-models. In this diagram more Entity and Attribute (in the physical realm table and column) details are displayed. The Sub-model enables a clear focus on the sub-schema of interest in the data model.