The following codes are running correctly, so I think that I have normally created a database, and opened it, and put a record in it, and normally close it.
But why can not I find the data file on my hard disk? Should I save it to a file somewhere?

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <db.h>

#define DATABASE "LesslieData.db"

int main()
{
     DB * dbp;
     int ret;
     DBT key, data;
     int Age = 20;
     char * name = "Lesslielee";
     
     ret = db_create(&dbp, NULL, 0); //Create a database
     if (ret != 0)
          {
               printf("Error in creating a database!");
               exit (1);
          }
     ret = dbp->open(dbp, NULL, DATABASE, NULL, DB_BTREE, DB_CREATE, 0664); //open the database
     if (ret != 0)
          {
               printf("Error in opening %s", DATABASE);
               exit(2);
          }
          
     memset(&key, 0, sizeof(DBT));
     memset(&data, 0 ,sizeof(DBT));
     
     key.data = name;
     key.size = strlen(name) + 1;
     
     data.data = &Age;
     data.size = sizeof(int);
     
     ret = dbp->put(dbp, NULL, &key, &data, DB_NOOVERWRITE);
     if (ret == DB_KEYEXIST)
          {
               printf("The key %s already exists.", name);
               exit(3);
          }
     if (dbp != NULL)
          {
               dbp->close(dbp, 0);
          }     
     return 0; //Success.
}

Message was edited by:
Lesslielee