Transformations > Union transformation > Advanced properties
  

Advanced properties

You can configure advanced properties for a Union transformation. The advanced properties control settings such as the tracing level for session log messages and whether the transformation is optional or required.
The properties that are available vary based on the mapping mode.
You can configure the following properties:
Property
Description
Tracing Level
Detail level of error and status messages that Data Integration writes in the session log. You can choose terse, normal, verbose initialization, or verbose data. Default is normal.
Optional
Determines whether the transformation is optional. If a transformation is optional and there are no incoming fields, the mapping task can run and the data can go through another branch in the data flow. If a transformation is required and there are no incoming fields, the task fails.
For example, you configure a parameter for the source connection. In one branch of the data flow, you add a transformation with a field rule so that only Date/Time data enters the transformation, and you specify that the transformation is optional. When you configure the mapping task, you select a source that does not have Date/Time data. The mapping task ignores the branch with the optional transformation, and the data flow continues through another branch of the mapping.