在Oracle Berkeley DB中打开DB环境出错

Question

我是数据库新手，我编写了这个实践程序来测试Berkeley BDB。我在打开环境时遇到麻烦-错误出现在我的控制台中并说:

testEnv_db.001: No such file or directory
Error opening database environment
DbEnv::open: No such file or directory

控制台程序的代码强烈地基于Berkeley DB Transactions指南中的示例，这里是程序的文本，直到错误，在int main()下。

String^ key_allkeys  = "_ALLKEYS";
String^ key_valcount = "_COUNT";
// 1. Print some information to the screen, prompt user to enter path for key-value pair location:
Console::WriteLine("Oracle Berkeley DB Example Database Creator");
Console::WriteLine();
Console::WriteLine("Enter the path to the text file of key-value pairs:");
String^ kv_path = Console::ReadLine();
// 2. Declare initial variables:
String^ totalkeys;
int totalval;
// 3. Open the database:
u_int32_t env_flags = DB_CREATE | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL | DB_INIT_TXN; 
std::string envHome("testEnv");
u_int32_t db_flags = DB_CREATE | DB_AUTO_COMMIT;
Db *dbp = NULL;
const char *file_name = "mydb.db";
DbEnv myEnv(0);
try 
{
    myEnv.open(envHome.c_str(), env_flags, 0);
    dbp = new Db(&myEnv, 0);
    dbp->open(NULL, file_name, NULL, DB_BTREE, db_flags, 0); 
} 
catch(DbException &e) 
{
    std::cerr << "Error opening database environment: " << std::endl;
    std::cerr << e.what() << std::endl;
    exc_block(); // Block
    return (EXIT_FAILURE);
}

很明显，程序在try/catch块周围失败。我已经阅读了手册(字面上是RTFM)，我无法弄清楚- DB_CREATE标志是为环境和数据库指定的，所以这里不应该有问题。

任何想法?

Answer 1

可能仅仅是因为testEnv目录不存在于运行程序的目录中?您必须自己创建环境主目录。

另外，您可能希望在打开环境时指定DB_RECOVER