Bug 197589 Need constant for automaic attribute name "DateTime"
Currently when set dateTimeLevelType for cube level, model will automatically create a built-in attribute "DateTime". But the name is hard-coded. We need a public constant for this name to allow UI to access it.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/PropertyCommand.java
}
			else if ( element instanceof OdaLevel )
			{
				OdaLevelAttribute attibute = new OdaLevelAttribute( );
				attibute.setName( "DateTime" ); 
				attibute
						.setDataType( DesignChoiceConstants.COLUMN_DATA_TYPE_DATETIME );
				struct = attibute;
			}
			if ( attributesPropertyDefn != null && struct != null )
			{
				try
				{
					cmd.addItem( new CachedMemberRef( attributesPropertyDefn ),
							struct );
				}
				catch ( SemanticException e )
				{
					assert false;
					stack.rollback( );
				}
			}
			stack.commit( );
			return;
		}
		PropertyRecord record = new PropertyRecord( element, prop, value );
		record.setEventTarget( getEventTarget( prop ) );
		getActivityStack( ).execute( record );
	}
	/**