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

The Physical Model

The physical model is the version of your model that captures the exact design of the physical database, including column datatypes and constraints, index assignments, denormalized tables, physical storage assignments, and other physical properties of the database that this product generates as a part of the schema for your target server. It is also used as an implementation model for a completed, fully attributed logical model.

Physical model creation is supported in the following ways:

• Independent of the logical model.
• Reverse engineered from an existing target database.
• Simultaneously created when you create the logical model.

You can view either the logical model or the physical model in a logical/physical model. You can also change the view back and forth between the two types of models by selecting either Logical or Physical from the dropdown located on the Standard toolbar. The objects that display in the Model Explorer and on the diagram window change according to the view you choose in the dropdown. For example, when you switch from a logical model to a physical model, the physical model that corresponds to the logical model displays, and the physical options that you can use to define the properties of physical model objects such as columns, tables, indexes, views, triggers, and stored procedures are activated.

You can customize your physical modeling options based on the characteristics of the target database you select. For example, column-level properties that are specific to your database appear in the Columns editor, including supported datatypes, null options, and display characteristics. Table-level properties that are specific to your database appear in the Table editor so you can define physical storage parameters or triggers. Once you define the model, it can be generated to your target database in the exact syntax required by your system.

Also supported is the definition of model objects in the logical model as logical only and the definition of model objects in the physical model as physical only. You can use these options, for example, to fully normalize a logical model and then denormalize the corresponding physical model to enhance database performance or model real-world data structures.

More information:

Comparison of Logical and Physical Models

Logical and Physical Model Denormalization

Switch Between Logical and Physical Models