Bug 123576 Data can't be retrieved when exporting data
Description: Data can't be retrieved when exporting data Steps to reproduce: 1.Preview the attached file in Web Viewer 2.Exported the data in table Expected result: The data is exported as a CSV file Actual result: No data is retrieved
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/DataExtractionTask.java
executionContext.setPresentationMode( true );
		report = new ReportParser( ).parse( ( (ReportRunnable) runnable )
				.getReport( ) );
		
		executionContext.setReport( report );
		setParameterValues( reportDocReader.getParameterValues( ) );
		
		IDataEngine dataEngine = executionContext.getDataEngine();
		dataEngine.prepare( report, appContext );
	}
	
	/*
	 * prepare the meta data of DataExtractionTask.
	 */
	private void prepareMetaData( )
	{
		if( isMetaDataPrepared == true ) 
			return;
			
		mapQueryToReportItem = report.getReportItemToQueryMap( );
		mapQueryToValueExprs = report.getQueryToValueExprMap( );
		
		
		try
		{
			loadResultSetMetaData( );
		}
		catch( EngineException e )
		{
			e.printStackTrace( );