About filtering lists of parameter values based on selected conditions

When you create or edit a parameter that is based on an item with a list of values (LOV), Discoverer enables you to filter the LOV by associating the parameter with one or more conditions. Discoverer displays the filtered LOV when you select parameter values to use in a worksheet. If you do not associate a condition with a parameter, then all parameter values are shown.

You could create a parameter based on the item City and associate a previously created condition Region = :Region with the City parameter. Notice that the Region condition includes a parameter value (Region) prefixed with a colon (:) indicating that it is a parameter value. The LOV for the City parameter will only display the Cities that satisfy the Region = :Region condition. In other words, if the end user has entered East for the parameter :Region, Discoverer will only display cities that belong to the East Region.

When you create a new parameter, by default, Discoverer selects active conditions associated with the parameter based on an item higher in the hierarchy. For example, if you create a Parameter on City Discoverer will associate the Region =:Region condition with the parameter. When Discoverer is unable to select any active conditions to associate with a parameter, you can manually select one or more conditions to associate with the parameter.

Notes

The conditions associated with a parameter are of worksheet scope, that is for a given parameter, you can associate different conditions for different sheets. For example, a parameter based on City could be associated with two conditions based on Region and State in one sheet, and with only one condition based on Region in another sheet.
You will not be able to associate a condition with a new parameter, where the condition includes a parameter value (e.g. Region =:Region), unless you create the condition before you create the parameter. For example, if you create a parameter City and want to associate the condition Region =:Region with the parameter City, you must create the condition before you create the parameter. This rule only applies to conditions that include a parameter. For example, if you create a parameter called City, then create a new condition Region ='East' (i.e. a condition without a parameter), you can associate this condition with the parameter City.

For more information, see: