C++ Db::set_flags方法代码示例

/* Initialize the database. */
void BulkExample::initDb(int dups, int sflag, int pagesize) {

	DbTxn *txnp;
	int ret;

	txnp = NULL;
	ret = 0;

	dbp = new Db(dbenv, 0);

	dbp->set_error_stream(&cerr);
	dbp->set_errpfx(progname);

	try{
		if ((ret = dbp->set_bt_compare(compare_int)) != 0)
			throwException(dbenv, NULL, ret, "DB->set_bt_compare");

		if ((ret = dbp->set_pagesize(pagesize)) != 0)
			throwException(dbenv, NULL, ret, "DB->set_pagesize");

		if (dups && (ret = dbp->set_flags(DB_DUP)) != 0)
			throwException(dbenv, NULL, ret, "DB->set_flags");

		if ((ret = dbenv->txn_begin(NULL, &txnp, 0)) != 0)
			throwException(dbenv, NULL, ret, "DB_ENV->txn_begin");

		if ((ret = dbp->open(txnp, DATABASE, "primary", DB_BTREE,
		    DB_CREATE, 0664)) != 0)
			throwException(dbenv, txnp, ret, "DB->open");

		if (sflag) {
			sdbp = new Db(dbenv, 0);

			if ((ret = sdbp->set_flags(DB_DUPSORT)) != 0)
				throwException(dbenv, txnp,
				    ret, "DB->set_flags");

			if ((ret = sdbp->open(txnp, DATABASE, "secondary",
			    DB_BTREE, DB_CREATE, 0664)) != 0)
				throwException(dbenv, txnp, ret, "DB->open");

			if ((ret =  dbp->associate(
			    txnp, sdbp, get_first_str, 0)) != 0)
				throwException(dbenv, txnp,
				    ret, "DB->associate");
		}

		ret = txnp->commit(0);
		txnp = NULL;
		if (ret != 0)
			throwException(dbenv, NULL, ret, "DB_TXN->commit");
	} catch(DbException &dbe) {
		cerr << "initDb " << dbe.what() << endl;
		if (txnp != NULL)
			(void)txnp->abort();
		throw dbe;
	}
}

// Open a Berkeley DB database
int
openDb(Db **dbpp, const char *progname, const char *fileName,
  DbEnv *envp, u_int32_t extraFlags)
{
    int ret;
    u_int32_t openFlags;

    try {
        Db *dbp = new Db(envp, 0);

        // Point to the new'd Db
        *dbpp = dbp;

        if (extraFlags != 0)
            ret = dbp->set_flags(extraFlags);

        // Now open the database */
        openFlags = DB_CREATE        | // Allow database creation
                    DB_THREAD        |
                    DB_AUTO_COMMIT;    // Allow autocommit

        dbp->open(NULL,       // Txn pointer
                  fileName,   // File name
                  NULL,       // Logical db name
                  DB_BTREE,   // Database type (using btree)
                  openFlags,  // Open flags
                  0);         // File mode. Using defaults
    } catch (DbException &e) {
        std::cerr << progname << ": openDb: db open failed:" << std::endl;
        std::cerr << e.what() << std::endl;
        return (EXIT_FAILURE);
    }

    return (EXIT_SUCCESS);
}

int main(int argc, const char* argv[]) {

  if (argc !=3) {
      cout << "usage: "<< argv[0] << " <filename> <db filename>" << endl;
      return 1;
  }

  const char* kDatabaseName = argv[2];
  const char* filename = argv[1];

  DbEnv env(0);
  Db* pdb;

  try {
    env.set_error_stream(&cerr);
    env.open("./", DB_CREATE | DB_INIT_MPOOL, 0);

    pdb = new Db(&env, 0);
    pdb->set_flags(DB_DUP);
    // Create (or clear its content if it exists) the database
    pdb->open(NULL, kDatabaseName, NULL, DB_BTREE, DB_CREATE | DB_TRUNCATE, 0);

    readfile(pdb, filename);
    readfile(pdb, "tables/jp.txt");

    // Clean up
    if (pdb != NULL) {
      pdb->close(0);
      delete pdb;
    }
    env.close(0);

  } catch (DbException& e) {
    cerr << "DbException: " << e.what() << endl;
    return -1;
  } catch (std::exception& e) {
    cerr << e.what() << endl;
    return -1;
  }

  return 0;
}

int main(int argc, const char* argv[]) {

  if (argc !=3) {
      cout << "usage: "<< argv[0] << " <filename> <db filename>" << endl;
      return 1;
  }

  const char* kDatabaseName = argv[2];
  const char* filename = argv[1];

  DbEnv env(0);
  Db* pdb;

  string line;

  bool datamode = false;

  try {

    env.set_error_stream(&cerr);
    env.open("./", DB_CREATE | DB_INIT_MPOOL, 0);

    pdb = new Db(&env, 0);
    // If you want to support duplicated records and make duplicated
    // records sorted by data, you need to call:
    //   pdb->set_flags(DB_DUPSORT);
    // Note that only Btree-typed database supports sorted duplicated
    // records

    // If the database does not exist, create it.  If it exists, clear
    // its content after openning.
    pdb->set_flags( DB_DUP );// | DB_DUPSORT);
    pdb->open(NULL, kDatabaseName, NULL, DB_BTREE, DB_CREATE | DB_TRUNCATE, 0);


    ifstream myfile (filename);
    if (myfile.is_open()) {
        int count = 0;
        while ( myfile.good() ) {
            //if (count++ > 10) {
            //    break;
            //} 
            getline (myfile,line);
            if (!datamode) {
                if ("[DATA]" == line ) {
                    datamode = true;
                }
                continue;
            }
            //cout << (int)line[8]  << endl;
            int index = 0;
            while (32 != (char)line[index]) {
                index++;
            }
            string cjkey = line.substr(0, index);
            while (32 == line[index]) {
                index++;
            }
            string cjdata = line.substr(index, (line.size()-index));
            cout << cjkey << "---" << cjdata << endl;
            Dbt key(const_cast<char*>(cjkey.data()), cjkey.size());
            Dbt value(const_cast<char*>(cjdata.data()), cjdata.size());
            pdb->put(NULL, &key, &value, 0);
        }
        myfile.close();
    } else { 
        cout << "Unable to open file";  
    }


    // You need to set ulen and flags=DB_DBT_USERMEM to prevent Dbt
    // from allocate its own memory but use the memory provided by you.
    string search("aa");
    Dbt key(const_cast<char*>(search.c_str()), search.size());
    char buffer[1024];
    Dbt data;
    data.set_data(buffer);
    data.set_ulen(1024);
    data.set_flags(DB_DBT_USERMEM);
    if (pdb->get(NULL, &key, &data, 0) == DB_NOTFOUND) {
      cerr << "Not found" << endl;
    } else {
      cout << "Found: " << "PPPPPP" <<buffer << "PPPPPP" << endl;
    }

    if (pdb != NULL) {
      pdb->close(0);
      delete pdb;
      // You have to close and delete an exisiting handle, then create
      // a new one before you can use it to remove a database (file).
      pdb = new Db(NULL, 0);
      //pdb->remove("access.db", NULL, 0);
      delete pdb;
    }
    env.close(0);

  } catch (DbException& e) {
    cerr << "DbException: " << e.what() << endl;
    return -1;
  } catch (std::exception& e) {
//.........这里部分代码省略.........