Bug 122854 There is redundant columns in "available columns" list in "export data" dialog.
Description: There is redundant columns in "available columns" list in "export data" dialog. Steps to reproduce: 1. Preview attached design in web viewer. 2. Select the table and click on "export" button. 3. There is a "detail" column name in "available columns" list which is not data set column.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/DataExtractionTask.java
/*
	 * map result set display name to result set name stored by DtE.
	 */
	protected HashMap mapDispNameToResultSetName;
	
	/*
	 * map String display name to IBaseQueryDefinition
	 */
	protected HashMap mapDispNameToQuery;
	
	/*
	 * map resultset name to IBaseQueryDefinition
	 */
	protected HashMap mapResultSetToQuery;
	
	/*
	 * have the metadata be prepared
	 */
	protected boolean isMetaDataPrepared = false;
	
	/*
	 * map report item to display name
	 */
	protected HashMap mapReportItemToDisplayName;
	/**
	 * the logger
	 */
	protected static Logger logger = Logger.getLogger( DteDataEngine.class
			.getName( ) );