Defining elements
Element constraints properties
Identity constraints allow you to indicate that element values must be unique within their specified scope.
You can use the Constraints page of an element property sheet to add the following constraints to an element declaration:
Tool | Tooltip | Description |
| Key Constraint | The element value must be a key within the |
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| specified scope. The scope of a key is the |
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| containing element in an instance document. A |
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| key must be unique, not null, and always |
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| present |
| Unique Constraint | The element value must be unique or null |
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| within the specified scope |
| KeyRef Constraint | The element value corresponds to those of the |
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| specified key or unique constraint |
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You can access directly to the Constraints page of an element property sheet through the contextual menu.
For more information on constraints, see section Defining identity constraints.
Element mapping properties
| Object mapping is the ability to establish a correspondence between objects |
| belonging to heterogeneous models and diagrams. |
| The Mapping page of an element property sheet allows you to map the |
| current element and its attributes to PDM or OOM objects. |
| Select a data source in the Mapping for dropdown listbox. If it is the first |
| time you define a mapping for an element, the Mapping for dropdown listbox |
| is empty. Click the Add a Mapping for a Data Source tool and select a data |
| source. |
Element Sources | The Element Sources page allows you to associate one or several PDM or |
page | OOM objects to the current element. |
| You can use the Add Objects tool to select objects from the PDMs or OOMs |
| opened in the current workspace. |
42 | PowerDesigner |