dbcxx.cpp~

来自「这是我用QT和TTS写的一个电话本管理系统」· CPP~ 代码 · 共 91 行

//g++ -o dbcxx -ggdb -I/usr/local/BerkeleyDB.4.6/include/ -L/usr/local/BerkeleyDB.4.6/lib/ -ldb -lpthread
#include <db_cxx.h> 
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#define DATABASE "phonebook.db"

// DB的函数执行完成后，返回0代表成功，否则失败
void print_error(int ret)
{
	if(ret != 0)
		printf("ERROR: %s\n",db_strerror(ret));
}

//数据结构DBT在使用前，应首先初始化，否则编译可通过但运行时报参数错误  
void init_DBT(DBT * key, DBT * data)
{
	memset(key, 0, sizeof(DBT));
	memset(data, 0, sizeof(DBT));
}

int main(void)
{
	DB *dbp;           
	DBT key, data;
	u_int32_t flags;  
	int ret;
	typedef struct customer
	{
		int  c_id;
		char name[10];
		char address[20];
		int  age;
	} CUSTOMER;
	CUSTOMER cust; 
	int key_cust_c_id = 1;
	
	//初始化结构体
	cust.c_id = 1;
	strncpy(cust.name, "promise", 9);
	strncpy(cust.address, "chengdu", 19);
	cust.age = 32;

	//首先创建数据库句柄 
	if ((ret = db_create(&dbp, NULL, 0)) != 0)
	{
		fprintf(stderr, "db_create: %s\n", db_strerror(ret));
		exit (1);
	}	
	//设置数据库参数
	flags = DB_CREATE; 
	// 创建一个数据库，使用HASH访问算法，本段代码演示对复杂数据结构的处理	
	if ((ret = dbp->open(dbp, NULL, "DATABASE", NULL, DB_HASH, flags, 0664)) != 0)
	{
		dbp->err(dbp, ret, "%s", DATABASE);
		exit (1);
	}	
	//insert data
	init_DBT(&key, &data);
	key.size = sizeof(int);
	key.data = &(cust.c_id);
	data.size = sizeof(CUSTOMER);
	data.data = &cust;
	if(ret = dbp->put(dbp, NULL, &key, &data,DB_NOOVERWRITE)==0)
	{
		printf("db: %s: key stored.\n", (char *)key.data);
	}
	else
		dbp->err(dbp, ret, "DB->put");
		
	//select data			
	memset(&cust, 0, sizeof(CUSTOMER));
	key.size = sizeof(int);
	key.data = &key_cust_c_id;
	data.data = &cust;
	data.ulen = sizeof(CUSTOMER); 
	data.flags = DB_DBT_USERMEM;
	if(dbp->get(dbp, NULL, &key, &data, 0)==0)
	{
		printf("db: %s: key retrieved: data was %s.\n", (char *)key.data, (char *)data.data);
	}
	else
		dbp->err(dbp, ret, "DB->get");
			
	printf("c_id = %d name = %s address = %s age = %d\n", 
		cust.c_id, cust.name, cust.address, cust.age);	
	if(dbp != NULL)
    		dbp->close(dbp, 0); 
	return 0;
}