Method forEachChild

src/DataTypes/DataTypeMap.cpp:175–181

}

void DataTypeMap::forEachChild(const DB::IDataType::ChildCallback & callback) const
{
    callback(*key_type);
    callback(*value_type);
    key_type->forEachChild(callback);
    value_type->forEachChild(callback);
}

/// Resolves a dynamic subcolumn like `map['key']` by parsing the key from the subcolumn name,
/// creating a `SerializationMapKeyValue` that knows how to read only the relevant bucket,