BDB c++例子，从源码编译到运行

第一步先下载源码，解压后 ./dist/configure --enable-cxx编译，然后make, make install

• --enable-cxx
  To build the Berkeley DB C++ API, enter --enable-cxx as an argument to configure.

默认的安装路径是：

/usr/local/BerkeleyDB.6.1/

代码如下：

#include <stdlib.h>
#include <string.h>
 
#include <iostream>
#include <iomanip>
#include <string>
 
#include <db_cxx.h>
 
using namespace std;
 
const char* kDatabaseName = "access.db";
 
int main() {
 
  string fruit("fruit");
  string apple("apple");
  string orange("orange");
 
  DbEnv env(0);
  Db* pdb;
 
  try {
    env.set_error_stream(&cerr);
    env.open("/Users/wangyi/db", 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->open(NULL, "access.db", NULL, DB_BTREE, DB_CREATE | DB_TRUNCATE, 0);
 
    Dbt key(const_cast<char*>(fruit.data()), fruit.size());
    Dbt value(const_cast<char*>(apple.data()), apple.size()+1);
    pdb->put(NULL, &key, &value, 0);
 
    Dbt value_orange(const_cast<char*>(orange.data()), orange.size()+1);
    pdb->put(NULL, &key, &value_orange, 0);
 
    // 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.
    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: " << buffer << 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("/Users/wangyi/db/access.db", NULL, 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;
}

编译：

g++ -o cass cassandra_demo.cpp -I /usr/local/BerkeleyDB.6.1/include/ -L /usr/local/BerkeleyDB.6.1/lib/ -ldb_cxx-6.1

运行：

export LD_LIBRARY_PATH=/usr/local/BerkeleyDB.6.1/lib/
./cass

参考：

https://docs.oracle.com/cd/E17275_01/html/programmer_reference/build_unix_conf.html

https://cxwangyi.wordpress.com/2010/10/10/how-to-use-berkeley-db/

http://stackoverflow.com/questions/2628227/berkeley-db-cant-compile-c-codes