Question

如何用MFC从MYSQL中读取数据

Answer 1

//下面的代码是一个实现C++连接MYSQL数据库的很好的例子
//这里用了建表，插入，检索，删表等常用功能
//我用VC++6.0生成，已经成功连接了。
//在VC++6.0中要想把做一下两步准备工作才可以。
//(1)Tools->Options->Directories->Include files中添加C:\Program Files\MySQL\MySQL Server 6.0\include
//(2)Tools->Options->Directories->Library files中添加C:\Program Files\MySQL\MySQL Server 6.0\lib\opt
//其实就是将头文件和库文件包含进来
//我觉得这个例子写的很好，再结合自己的试验，特地介绍给大家！

#include <winsock.h>
#include <iostream>
#include <string>
#include <mysql.h>
using namespace std;

#pragma comment(lib, "ws2_32.lib")
#pragma comment(lib, "libmysql.lib")

//单步执行，不想单步执行就注释掉
#define STEPBYSTEP

int main() {
cout << "****************************************" << endl;

#ifdef STEPBYSTEP
system("pause");
#endif

//必备的一个数据结构
MYSQL mydata;

//初始化数据库
if (0 == mysql_library_init(0, NULL, NULL)) {
cout << "mysql_library_init() succeed" << endl;
} else {
cout << "mysql_library_init() failed" << endl;
return -1;
}

#ifdef STEPBYSTEP
system("pause");
#endif

//初始化数据结构
if (NULL != mysql_init(&mydata)) {
cout << "mysql_init() succeed" << endl;
} else {
cout << "mysql_init() failed" << endl;
return -1;
}

#ifdef STEPBYSTEP
system("pause");
#endif

//在连接数据库之前，设置额外的连接选项
//可以设置的选项很多，这里设置字符集，否则无法处理中文
if (0 == mysql_options(&mydata, MYSQL_SET_CHARSET_NAME, "gbk")) {
cout << "mysql_options() succeed" << endl;
} else {
cout << "mysql_options() failed" << endl;
return -1;
}

#ifdef STEPBYSTEP
system("pause");
#endif

//连接数据库
if (NULL
!= mysql_real_connect(&mydata, "localhost", "root", "test", "test",
3306, NULL, 0))
//这里的地址，用户名，密码，端口可以根据自己本地的情况更改
{
cout << "mysql_real_connect() succeed" << endl;
} else {
cout << "mysql_real_connect() failed" << endl;
return -1;
}

#ifdef STEPBYSTEP
system("pause");
#endif

//sql字符串
string sqlstr;

//创建一个表
sqlstr = "CREATE TABLE IF NOT EXISTS user_info";
sqlstr += "(";
sqlstr +=
"user_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'Unique User ID',";
sqlstr +=
"user_name VARCHAR(100) CHARACTER SET gb2312 COLLATE gb2312_chinese_ci NULL COMMENT 'Name Of User',";
sqlstr +=
"user_second_sum INT UNSIGNED NOT NULL DEFAULT 0 COMMENT 'The Summation Of Using Time'";
sqlstr += ");";
if (0 == mysql_query(&mydata, sqlstr.c_str())) {
cout << "mysql_query() create table succeed" << endl;
} else {
cout << "mysql_query() create table failed" << endl;
mysql_close(&mydata);
return -1;
}

#ifdef STEPBYSTEP
system("pause");
#endif

//向表中插入数据
sqlstr =
"INSERT INTO user_info(user_name) VALUES('公司名称'),('一级部门'),('二级部门'),('开发小组'),('姓名');";
if (0 == mysql_query(&mydata, sqlstr.c_str())) {
cout << "mysql_query() insert data succeed" << endl;
} else {
cout << "mysql_query() insert data failed" << endl;
mysql_close(&mydata);
return -1;
}

#ifdef STEPBYSTEP
system("pause");
#endif

//显示刚才插入的数据
sqlstr = "SELECT user_id,user_name,user_second_sum FROM user_info";
MYSQL_RES *result = NULL;
if (0 == mysql_query(&mydata, sqlstr.c_str())) {
cout << "mysql_query() select data succeed" << endl;

//一次性取得数据集
result = mysql_store_result(&mydata);
//取得并打印行数
int rowcount = mysql_num_rows(result);
cout << "row count: " << rowcount << endl;

//取得并打印各字段的名称
unsigned int fieldcount = mysql_num_fields(result);
MYSQL_FIELD *field = NULL;
for (unsigned int i = 0; i < fieldcount; i++) {
field = mysql_fetch_field_direct(result, i);
cout << field->name << "\t\t";
}
cout << endl;

//打印各行
MYSQL_ROW row = NULL;
row = mysql_fetch_row(result);
while (NULL != row) {
for (int i = 0; i < fieldcount; i++) {
cout << row[i] << "\t\t";
}
cout << endl;
row = mysql_fetch_row(result);
}

} else {
cout << "mysql_query() select data failed" << endl;
mysql_close(&mydata);
return -1;
}

#ifdef STEPBYSTEP
system("pause");
#endif

//删除刚才建的表
sqlstr = "DROP TABLE user_info";
if (0 == mysql_query(&mydata, sqlstr.c_str())) {
cout << "mysql_query() drop table succeed" << endl;
} else {
cout << "mysql_query() drop table failed" << endl;
mysql_close(&mydata);
return -1;
}
mysql_free_result(result);
mysql_close(&mydata);
mysql_server_end();

system("pause");
return 0;
}