public static str lookupDatasourceOfQuery(Query _query)
{
    Query                   query = _query;
    QueryBuildDataSource    qbds;
    int                     dsIterator;
    Map                     map = new Map(Types::String, Types::String);
    ;

    for (dsIterator = 1; dsIterator <= query.dataSourceCount(); dsIterator++)
    {
        qbds = query.dataSourceNo(dsIterator);
        map.insert(qbds.name(), qbds.name());
    }

    return pickList(map, "Data source", "Data sources");

}