Extended model definitions (.XEM files) provide means for customizing and extending PowerDesigner metaclasses, parameters and generation. Extended model definitions are typed like models in PowerDesigner. You create an extended model definition for a specific type of model and you cannot share these files between heterogeneous models.
In the case of requirements models, you can use extended model definitions as methodological supports for requirements management:
Custom checks verify that methodological statements are satisfied. For example, each requirement of scenario type must be associated with a use case in an OOM
You can customize the list of values for some properties. See Requirement Property Sheet Details Tab
You can initialize the default values of a requirement, just after its creation, by using the Initialize event handler
When you create a new requirements model, you can select one or several extended model definitions and attach them to the model from the New dialog box.
You can choose one of the following options:
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Option |
Description |
|---|---|
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Share |
Current extended model definition constantly refers to the extended model definition stored in the Resource Files\Extended Model Definitions directory. Any changes made to the extended model definition are shared by all linked XEM |
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Copy |
Current extended model definition is a unique copy of the extended model definition stored in the Resource Files\Extended Model Definitions directory. The current extended model definition is independent of the original one, so modifications made to the extended model definition in the Resource Files\Extended Model Definitions directory are not available to the copied XEM. This one is saved with the requirements model and cannot be used without it |
For more information on extended model definitions, see "Extended Model Definitions" in the Resource Files and the Public Metamodel chapter of the Customizing and Extending PowerDesigner manual.