Bug 207561 [Regression] Conversion errror when preview the attached report design
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
removeAllAvailableDbObjects( );
		setRootElement( );
		setRefreshInfo( );
		if ( isSchemaSupported )
		{
			populateSchemaList( );
		}
		else
		{
			populateTableList( );
		}
		addFetchDbObjectListener( );
		
		if ( rootNode != null )
		{
			selectNode( rootNode );
		}
	}
	/**
	 * 
	 * @return
	 */
	private DataSetDesign getDataSetDesign( )
	{
		if ( dataSetDesign == null )
			dataSetDesign = this.getInitializationDesign( );
		return dataSetDesign;
	}