Use mapping parameters in the session properties to alter certain mapping attributes. For example, use a mapping parameter in a transformation override to override a filter or user-defined join in a Source Qualifier transformation.
If you use mapping variables in a session, you can clear any of the variable values saved in the repository by editing the session. When you clear the variable values, the Integration Service uses the values in the parameter file the next time you run a session. If the session does not use a parameter file, the Integration Service uses the values assigned in the pre-session variable assignment. If there are no assigned values, the Integration Service uses the initial values defined in the mapping.
To view or delete values for mapping variables saved in the repository:
In the Navigator window of the Workflow Manager, right-click the Session task and select View Persistent Values.
You can see the variable name and value.
Click Delete Values to delete existing variable values.