Function convertToSubcolumns

src/DataTypes/NestedUtils.cpp:513–554

}

NamesAndTypesList convertToSubcolumns(const NamesAndTypesList & names_and_types)
{
    auto nested_types = getSubcolumnsOfNested(names_and_types);
    auto res = names_and_types;

    for (auto & name_type : res)
    {
        if (!isArray(name_type.type))
            continue;

        auto split = splitName(name_type.name);
        if (split.second.empty())
            continue;

        if (name_type.isSubcolumn())
        {
            /// If this is a subcolumn (e.g. `c0.c2.null` — subcolumn `null` of `c0.c2`)
            /// and its parent column is part of a Nested group, remap it to be a subcolumn
            /// of the Nested type (e.g. subcolumn `c2.null` of Nested `c0`).
            /// This ensures the Nested serialization is used, which handles shared offsets correctly.
            auto name_in_storage = name_type.getNameInStorage();
            auto storage_split = splitName(name_in_storage);
            if (!storage_split.second.empty())
            {
                auto it = nested_types.find(storage_split.first);
                if (it != nested_types.end())
                {
                    auto new_subcolumn = concatenateName(storage_split.second, name_type.getSubcolumnName());
                    if (auto subcolumn_type = it->second->tryGetSubcolumnType(new_subcolumn))
                        name_type = NameAndTypePair{storage_split.first, new_subcolumn, it->second, subcolumn_type};
                }
            }
            continue;
        }

        auto it = nested_types.find(split.first);
        if (it != nested_types.end())
            name_type = NameAndTypePair{split.first, split.second, it->second, it->second->getSubcolumnType(split.second)};
    }

    return res;
}


void validateArraySizes(const Block & block)