storage_engine.cpp
ValueDicts* DbRelation::project(Handles *handles, const ColumnNames *column_names) {
    ValueDicts *ret = new ValueDicts();
    for (auto const& handle: *handles)
        ret->push_back(project(handle, column_names));
    return ret;
}
// Do a projection for each of a list of handles

Do a projection for each of a list of handles
Do a projection for each of a list of handles
ValueDicts* DbRelation::project(Handles *handles, const ColumnNames *column_names) {
    ValueDicts *ret = new ValueDicts();
    for (auto const& handle: *handles)
        ret->push_back(project(handle, column_names));
    return ret;
}
ValueDicts * DbRelation :: project ( Handles * handles , const ColumnNames * column_names ) { ValueDicts * ret = new ValueDicts ( ) ; for ( auto const & handle : * handles ) ret -> push_back ( project ( handle , column_names ) ) ; return ret ; }
Do a projection for each of a list of handles
Do a projection for each of a list of handles