To control the results of multiple steps in a Selection
object, specify the Action
property for each Step
object. The following values (which are found in oracle.dss.selection.step.Step
) are available for the Action property:
SELECT -- (Default value) Replaces the current selection with new members
ADD -- Adds the members of the new step to the current selection
KEEP -- Keeps the members of the new step that were already present in the current selection and discards all other members.
REMOVE -- Removes from the current selection any members that are specified in the new step.
Assume that a selection consists of the following two steps:
Step A specifies the members: Boston, Chicago, and Denver
Step B specifies the members: Boston and Austin
Step B follows Step A. The following list shows how the results of this selection differ depending on the action that is specified for Step B:
Step B action: SELECT -- Result: Boston and Austin (that is, only B is included)
Step B action: ADD -- Result: Boston, Chicago, Denver, and Austin (that is, the union of A and B is included)
Step B action: KEEP -- Result: Boston (that is, only members that are common to both A and B are kept; also referred to as the intersection of A and B)
Step B action: REMOVE -- Result: Chicago and Denver (that is, any members in B are removed from the current selection )