The logical model and the physical model are separate models. The logical model enables you to represent business information and define business rules. The physical model enables you to focus on the physical implementation of the model in a database. Both the logical and physical models represent design layers in the application development process.
The logical and physical models can look very different, depending on the notation selected (IDEF1X, IE, or DM), and the display options selected.
You can use erwin DM to create a logical model that is different from, but related to a physical model. For example, you can flag certain objects in the logical model as logical only so that they do not appear in a corresponding physical model, and you can flag certain objects in the physical model as physical only so that they do not appear in a corresponding logical model.
Other items are available for one modeling environment, but not the other. For example, you can create many-to-many relationships and subtype relationships in the logical model (these constructs must be resolved in the physical model), and you can include views and view relationships in the physical model only.
Support for the separation of the logical model from the physical model also includes features and options in the user interface and dialogs, including:
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