OBIEE 11g: First Value in the Column Prompt is NULL or Blank

Applies to:

Business Intelligence Server Enterprise Edition - Version 11.1.1.6.0 and later
Business Intelligence Suite Enterprise Edition - Version 11.1.1.6.0 and later
Information in this document applies to any platform.

Symptoms

The first value in a column in a dashboard prompt is showing as "NULL" or a blank in the LOV of dashboard prompt.  For example:
      NULL
      10
      20
      30
      40

There is no null in the data in the database.

Cause

This is working as intended.
The prompts always include a blank line at the top of the list so that any values can be unselected.  Null appears instead of a blank line if "Nullable" is checked in the physical layer  of the repository.

Solution

To stop NULL being displayed:
1. Launch Oracle Business Intelligence Administration Tool.
2. Go to the physical layer and right click the column for dashboard prompt.
3. Open the Column property and uncheck "Nullable".
4. Save the changes to the rpd file.
5. Re-start the services.