Chapter 15 DBMS-Specific Features

Why build a logical model?

The logical PDM is a physical model with standard objects, and without DBMS specific physical options and generation capabilities.

In the database design process, you use a logical model as an intermediary step between conceptual and physical design:

• Start with a CDM containing entities, attributes, relationships, domains, data items and business rules
• Generate a logical model (PDM with the <Logical Model> DBMS). Create indexes and specify FK column names and other common features
• Generate a set of PDMs, each targeted to a specific DBMS implementation. Define physical options and other DBMS specific features

This design process allows you to keep everything consistent in a large development effort.

For more information on PDM generation, see the Generating Other Models from a PDM chapter.

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