Lookup on nested boost multi_index_container

Question

Consider following code

struct VersionData
{
    VersionData();
    VersionData(VersionData&& rhs);
    int     m_versionId;
    int     m_weight;
    in         


        

Answer 1

So indeed, instead of using nested containers, like that (live on Coliru)

You could/should implement it as a single /table/ (after all, this is a table with several indices):

Live On Coliru

#include 
#include 
#include 
#include 

namespace bmi = boost::multi_index;

struct VersionRecord {
    int  m_subdeliveryGroupId;
    int  m_retargetingId;
    int  m_versionId;
    int  m_weight;
    int  m_pId;
    bool m_hdi;

    friend std::ostream& operator<<(std::ostream& os, VersionRecord const& record) {
        return os << "{ " << record.m_subdeliveryGroupId << " " << record.m_retargetingId << " "
            << record.m_versionId << " " << record.m_weight << " " << record.m_pId << " " << record.m_hdi << " }";
    }
};

typedef boost::multi_index_container<
    VersionRecord,
    bmi::indexed_by<
        bmi::ordered_unique<
            bmi::tag,
            bmi::composite_key<
                VersionRecord,
                bmi::member,
                bmi::member
            >
        >,
        bmi::ordered_non_unique<
            bmi::tag,
            bmi::member
        >
    >
> VersionTable;

#include 
#include 

int main() {

    auto table = VersionTable { 
        { 21, 10,                1,  100, 123, false },
        { 9,  27,                2,  90,  123, false },
        { 12, 25,                3,  110, 123, true  },
        { 10, 33, /*version 8:*/ 8,  80,  123, false },
        { 4,  38,                5,  101, 124, false },
        { 33, 7,                 6,  91,  124, false },
        { 34, 27,                7,  111, 124, true  },
        { 9,  11, /*version 8:*/ 8,  81,  124, false },
        { 0,  12,                9,  99,  125, false },
        { 35, 39, /*version 8:*/ 8,  89,  125, false },
        { 15, 15,                11, 109, 125, true  },
        { 25, 32, /*version 8:*/ 8,  79,  125, false },
    };

    // debug table output
    assert(table.size()==12);
    for (auto& record : table) std::cout << record << "\n";

    // so now you can do:
    auto& idx = table.get();

    std::cout << "---\nQuerying for version id 8:\n";
    for (auto& record : boost::make_iterator_range(idx.equal_range(8)))
        std::cout << record << "\n";
}

Which prints:

{ 0 12 9 99 125 0 }
{ 4 38 5 101 124 0 }
{ 9 11 8 81 124 0 }
{ 9 27 2 90 123 0 }
{ 10 33 8 80 123 0 }
{ 12 25 3 110 123 1 }
{ 15 15 11 109 125 1 }
{ 21 10 1 100 123 0 }
{ 25 32 8 79 125 0 }
{ 33 7 6 91 124 0 }
{ 34 27 7 111 124 1 }
{ 35 39 8 89 125 0 }
---
Querying for version id 8:
{ 25 32 8 79 125 0 }
{ 35 39 8 89 125 0 }
{ 10 33 8 80 123 0 }
{ 9 11 8 81 124 0 }

Alternatively, you can bolt an intrusive container on top of the VersionsData records. This however, complicates the design (you either have to use auto_unlink node hooks (sacrificing thread safety control) or you have to make sure the containers are in synch all the time.