lmdb-safe/examples/multi.cc

#include "../lmdb-safe.hh"

#include <unistd.h>

#include <iostream>

using namespace std;
using namespace LMDBSafe;

int main()
{
    unlink("./multi");
    auto env = getMDBEnv("./multi.lmdb", MDB_NOSUBDIR, 0600);
    auto dbi = env->openDB("qnames", MDB_DUPSORT | MDB_CREATE);

    auto txn = env->getRWTransaction();
    txn->clear(dbi);

    txn->put(dbi, "bdb", "old");
    txn->put(dbi, "lmdb", "hot");
    txn->put(dbi, "lmdb", "fast");
    txn->put(dbi, "lmdb", "zooms");
    txn->put(dbi, "lmdb", "c");
    txn->put(dbi, "mdb", "old name");

    string_view v1;
    if (!txn->get(dbi, "mdb", v1)) {
        cout << v1 << endl;
    } else {
        cout << "found nothing" << endl;
    }
    txn->commit();

    txn = env->getRWTransaction();
    auto cursor = txn->getRWCursor(dbi);

    MDBOutVal key, data;

    for (int rc = cursor.find("lmdb", key, data); !rc; rc = cursor.get(key, data, MDB_NEXT_DUP)) {
        cout << key.get<string_view>() << " = " << data.get<string_view>() << endl;
    }

    cout << "Dump of complete database: " << endl;
    for (int rc = cursor.first(key, data); !rc; rc = cursor.next(key, data)) {
        cout << key.get<string_view>() << " = " << data.get<string_view>() << endl;
    }
    cout << "Done!" << endl;

    cout << "Now going to delete 'lmdb' keys" << endl;

    for (int rc = cursor.first(key, data); !rc; rc = cursor.next(key, data)) {
        if (key.get<string_view>() == "lmdb")
            cursor.del();
    }

    cout << "Complete database after deleting 'lmdb' keys: " << endl;

    for (int rc = cursor.first(key, data); !rc; rc = cursor.next(key, data)) {
        cout << key.get<string_view>() << " = " << data.get<string_view>() << endl;
    }
}