In this example, we will quickly add a new attribute directly from the property sheet of an object. PowerDesigner will manage the creation of the extension file and creation of all the necessary extensions.
- Click on the Property Sheet Menu button at the bottom-left of the property sheet, to the right of the More/Less button, and select New Attribute.
 
- In the New Attribute dialog, enter Latency in the Name field, select String for the data type.
 
- Click the ellipsis button to the right of the List of values field, enter the following  list of predefined values, and then click OK:
 - Batch
 
- Real-Time
 
- Scheduled
 
  
- [optional] Select Scheduled in the Default value field.
 
- [optional] Click Next to specify the property sheet page where you want the new attribute to appear. Here, we'll leave the default, so its inserted on the General tab.