Chapter 4 Building Conceptual Data Models
You can use the data item as an entity attribute by attaching it to an entity. This choice does not create a new data item. The resulting entity attribute has the same code as the data item.
If you select Allow Reuse as a data item option, the same data item can be an entity attribute for more than one entity. However, you cannot reuse a data item that is an identifier.
Reusing a data item does not create a new data item. The data item and the corresponding entity attributes have the same code.
A new data item can be added by creating a new one or copying an existing one as the basis for a new one. The following specific tools are available to add data items:
Tool | Description/Effect of Model Options |
---|---|
Add Data Item | This tool is only available if the Allow Reuse option is selected in Model Options.
This tool displays all model data items. If you click this tool and select a data item that is unused in the list of entity attributes, a new data item is created and added to the list. If you click this tool and select a currently used data item, the data item is copied and used as the basis for a new data item |
Reuse Data Item | No new unused data item can be created with this tool.
This tool displays all model data items. If you click this tool and select a data item that is used in the list of entity attributes, the data item is copied, added to the list and used as the basis for a new data item |
To use a data item as an entity attribute:
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