Chapter 2 Getting Started with Data Modeling

Logical Data Models

A Logical Data Model helps you design a database structure and perform some database denormalization actions independent of any specific DBMS physical requirements.

You can use a logical model as an intermediary step in the database design process between the conceptual and physical designs:

• Start with a CDM containing entities, attributes, relationships, domains, data items and business rules. If need be, you may develop the CDM in several design steps starting from a high level model to a low level CDM
• Generate an LDM. Create indexes and specify FK column names and other common features
• Generate one or more PDMs, each targeted to a specific DBMS implementation

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

To create an LDM, see Creating a Data Model. For detailed information about logical diagrams, see "Logical Diagram Basics" in the Building Conceptual and Logical Diagrams chapter.

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