Bug 134665 report become dirty after previewing data set
steps to reproduce: - create a report - create a data source - create a data set - save the report - open the data set - preview results expected behavior: - the state of the report remains unchanged actual behavior: - the state of the report changed, as the report became dirty
data/org.eclipse.birt.report.data.adapter/src/org/eclipse/birt/report/data/adapter/impl/DataSetMetaDataHelper.java
private IResultMetaData getRealMetaData( String dataSetName )
			throws BirtException
	{
		QueryDefinition query = new QueryDefinition( );
		query.setDataSetName( dataSetName );
		query.setMaxRows( 1 );
		return new QueryExecutionHelper( dataEngine, modelAdaptor, moduleHandle ).executeQuery( query,
				null,
				null,
				null )
				.getResultMetaData( );
	}
	/**
	 * 
	 * @param dataSetHandle
	 * @return
	 * @throws BirtException
	 */
	IResultMetaData refreshMetaData( DataSetHandle dataSetHandle )
			throws BirtException
	{
		dataSetHandle.setCachedMetaData( StructureFactory.createCachedMetaData( ) );
		IResultMetaData rsMeta = this.getDataSetMetaData( dataSetHandle, false );
		for ( int i = 1; i <= rsMeta.getColumnCount( ); i++ )
		{
			ResultSetColumn rsc = StructureFactory.createResultSetColumn( );
			rsc.setColumnName( ( rsMeta.getColumnAlias( i ) == null || rsMeta.getColumnAlias( i )
					.trim( )
					.length( ) == 0 ) ? rsMeta.getColumnName( i )
					: rsMeta.getColumnAlias( i ) );