Date Format Configuration in Obiee11g

Date Format Configuration

1. Backup localedefinitions.xml file in the directory
ORACLE_HOME\bifoundation\web\display\

Ex - \OBIEE\app\fmw\Oracle_BI1\bifoundation\web\display\localedefinitions.xml

2. After taking a backup of Existing localedefinitions.xml file and Find
dataShortFormat and change the date Format according to your 

Requirement
there are many date Format like

For example I want Date format like 09-Apr-2013
I am changing it to dd-MMM-yyyy 

Note -  There are Multiple Languages in localedefinitions.xml file.Change it according to Requirement

Save the file and re-start all of the BI Services through Enterprise Manager.