Bug 124251 the data cann't been exported.
Description: the data cann't been exported. Steps to reproduce: 1. new a report 2. new a datasource and a data set(DS_A) 3. use an external library 4. drag a table to the report layout from the imported library 5. insert an another table into the layout of the report and bind the data set(DS_A) 6. preview in the 'Web Viewer' and export the data Actual result: The data can been exported. Expect result: The data can been exporteded
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/DataExtractionTask.java
String resultSetName = (String) resultSetIter.next();
				mapDispNameToResultSetName.put(displayName, resultSetName);
				this.mapResultSetNameToQuery.put( resultSetName, query );
			}
		}
		
		isMetaDataPrepared = true;
	}
	
	/*
	 * load map from query id to result set id from report document.
	 */
	private void loadResultSetMetaData( ) throws EngineException
	{
		IDocArchiveReader reader = reportDocReader.getArchive( );
		try
		{
			DataInputStream dis = new DataInputStream( reader 
					.getStream( AbstractDataEngine.DATA_META_STREAM ));
			
			mapQueryIDToResultSetName = new HashMap( );
			int size = IOUtil.readInt( dis );
			for( int i=0; i<size; i++ )
			{
				String queryId = IOUtil.readString( dis );
				LinkedList ridList = new LinkedList( );
				readStringList( dis, ridList );
				mapQueryIDToResultSetName.put( queryId, ridList );
			}
			dis.close( );