C++使用MySQL官方的C API访问MySQL数据库
这篇文章是一个简单的C++使用MySQL官方的C API访问MySQL数据库的代码示例。
//main.h
#ifndef _H_
#define _H_
#include<stdio.h>
#include<Windows.h>
#include<mysql.h>
#pragma comment(lib,"libmysql.lib")
#define insert_prepare "insert into test_tb value(? , ? , ?)"
//菜单函数
void f_printmenu(void);
//新建函数
int f_insert(MYSQL* mysql);
//删除函数
int f_delete(MYSQL* mysql);
//修改函数
int f_modify(MYSQL* mysql);
//查询函数
int f_select(MYSQL* mysql);
#endif
//数据表包含商品编号、名称、价格
//main.cpp
#include"main.h"
int main()
{
#if 1
enum { _insert = 1, _delete, _modify, _select };
#else
const int _insert = 1, _delete = 2, _modify = 3, _select = 4;
#endif
int choose = 0;
MYSQL* mysql;//mysql句柄
//初始化mysql句柄
mysql = mysql_init(NULL);
if (mysql == NULL)
{
printf("mysql_init error\n");
system("pause");
return -1;
}
printf("mysql_init ok\n");
//连接mysql数据库
mysql = mysql_real_connect(mysql, "localhost", "xxx", "xxx", "test_db", 3306, NULL, 0);//返回值和参数mysql是相同值
if (mysql == NULL)
{
printf("mysql_real_connect error\n");
system("pause");
return -1;
}
printf("mysql_real_connect ok");
//获取当前进程/会话使用的字符集
printf("before,字符集:%s\n", mysql_character_set_name(mysql));
/*设置当前进程/会话的默认字符集
mysql_set_character_set(mysql,"utf8");
printf("after,字符集:%s\n", mysql_character_set_name(mysql));*/
f_printmenu();
scanf("%d", &choose);
system("cls");
while (choose)
{
switch (choose)
{
case _insert:
f_insert(mysql);
break;
case _delete:
f_delete(mysql);
break;
case _modify:
f_modify(mysql);
break;
case _select:
f_select(mysql);
break;
default:
printf("输入错误\n");
break;
}
f_printmenu();
scanf("%d", &choose);
system("cls");
}
//关闭mysql句柄
mysql_close(mysql);
system("pause");
return 0;
}
//菜单函数
void f_printmenu(void)
{
printf("\
******************\n\
* 菜单 *\n\
* 1.新建 *\n\
* 2.删除 *\n\
* 3.修改 *\n\
* 4.查询 *\n\
* 0.退出 *\n\
******************\n");
}
//新建函数
int f_insert(MYSQL* mysql)
{
int number = 0;
char* tpye = (char*)malloc(20);
float price = 0;
int num = 0;
int iden = 0;
MYSQL_STMT* stmt = NULL;
int param_count = 0;
MYSQL_BIND my_bind[3];
unsigned long len = 0;
do
{
printf("请输入编号\n");
scanf("%d", &number);
printf("请输入类型\n");
scanf("%s", tpye);
printf("请输入价格\n");
scanf("%f", &price);
len = strlen(tpye);
//初始化预处理环境句柄mysql_stmt
stmt = mysql_stmt_init(mysql);
if (stmt == NULL)
{
printf("mysql_stmt_init error:%s\n", mysql_error(mysql));
system("pause");
return -1;
}
printf("mysql_stmt_init ok\n");
//向初始化后的环境句柄mysql_stmt添加sql命令
if (mysql_stmt_prepare(stmt, insert_prepare, strlen(insert_prepare)))
{
printf("mysql_stmt_prepare error:%s\n", mysql_stmt_error(stmt));
system("pause");
return -1;
}
printf("mysql_stmt_prepare ok\n");
//获取需要绑定变量的个数，即？数量
param_count = mysql_stmt_param_count(stmt);
if (param_count != 3)
{
printf("mysql_stmt_param_count error:%s\n", mysql_stmt_error(stmt));
system("pause");
return -1;
}
printf("mysql_stmt_param_count ok\n");
//设置需要绑定的实参
memset(my_bind, 0, sizeof(my_bind));
my_bind[0].buffer_type = MYSQL_TYPE_LONG;
my_bind[0].buffer = (char*)&number;
my_bind[0].is_null = 0;
my_bind[0].length = 0;
my_bind[1].buffer_type = MYSQL_TYPE_STRING;
my_bind[1].buffer = tpye;
my_bind[1].is_null = 0;
my_bind[1].length = &len;
my_bind[2].buffer_type = MYSQL_TYPE_FLOAT;
my_bind[2].buffer = (char*)&price;
my_bind[2].is_null = 0;
my_bind[2].length = 0;
//绑定？对应的实参
if (mysql_stmt_bind_param(stmt, my_bind))
{
printf("mysql_stmt_bind_param error:%s\n", mysql_stmt_error(stmt));
system("pause");
return -1;
}
printf("mysql_stmt_bind_param ok\n");
//执行预处理的sql命令
if (mysql_stmt_execute(stmt))
{
printf("mysql_stmt_execute error:%s\n", mysql_stmt_error(stmt));
system("pause");
return -1;
}
printf("mysql_stmt_execute ok\n");
//获取影响的行数
num = mysql_stmt_affected_rows(stmt);
printf("新建%d行记录\n", num);
printf("继续新建输入1，返回菜单输入0\n");
scanf("%d", &iden);
} while (iden);
//关闭预处理的环境句柄mysql_stmt
if (mysql_stmt_close(stmt))
{
printf("mysql_stmt_close error:%s\n", mysql_stmt_error(stmt));
system("pause");
return -1;
}
printf("mysql_stmt_close ok\n");
return 0;
}
//删除函数
int f_delete(MYSQL* mysql)
{
int number = 0;
char* cnumber = (char*)malloc(10);
char* buffer = (char*)malloc(100);
int iden = 0;
do
{
printf("请输入编号\n");
scanf("%d", &number);
itoa(number, cnumber, 10);
strcpy(buffer, "delete from test_tb where test_tb.number=");
strcat(buffer, cnumber);
//开启事务处理，并且设置手动commit
mysql_query(mysql, "start transcation");
mysql_query(mysql, "set autocommit=0");
//向mysql发送操作命令
int ret = mysql_query(mysql, buffer);
if (ret == 0)
{
printf("mysql_query ok\n");
//获取影响的行数
int num = mysql_affected_rows(mysql);//不能放在commit之后，不然返回的值不对
printf("删除%d行记录\n", num);
mysql_query(mysql, "commit");
}
else
{
printf("mysql_query error:%s\n", mysql_error(mysql));
mysql_query(mysql, "callback");
}
printf("继续新建输入1，返回菜单输入0\n");
scanf("%d", &iden);
} while (iden);
return 0;
}
//修改函数
int f_modify(MYSQL* mysql)
{
int number = 0;
char* cnumber = (char*)malloc(10);
int price = 0;
char* cprice = (char*)malloc(10);
char* buffer = (char*)malloc(100);
int iden = 0;
do
{
printf("请输入编号\n");
scanf("%d", &number);
printf("请输入价格\n");
scanf("%d", &price);
itoa(number, cnumber, 10);
gcvt(price, 10, cprice);
strcpy(buffer, "update test_tb set test_tb.price=");
strcat(buffer, cprice);
strcat(buffer, "where test_tb.number=");
strcat(buffer, cnumber);
//开启事务处理，并且设置手动commit
mysql_query(mysql, "start transcation");
mysql_query(mysql, "set autocommit=0");
//向mysql发送操作命令
int ret = mysql_query(mysql, buffer);
if (ret == 0)
{
printf("mysql_query ok\n");
//获取影响的行数
int num = mysql_affected_rows(mysql);
printf("修改%d行记录\n", num);
mysql_query(mysql, "commit");
}
else
{
printf("mysql_query error:%s\n", mysql_error(mysql));
mysql_query(mysql, "callback");
}
printf("继续新建输入1，返回菜单输入0\n");
scanf("%d", &iden);
} while (iden);
return 0;
}
//查询函数
int f_select(MYSQL* mysql)
{
MYSQL_RES* res = NULL;
MYSQL_ROW row;
MYSQL_FIELD* field = NULL;
int number = 0;
char* buffer = (char*)malloc(100);
char* cnumber = (char*)malloc(10);
int iden = 0;
do
{
printf("请输入编号\n");
scanf("%d", &number);
itoa(number, cnumber, 10);
strcpy(buffer, "select * from test_tb where number = ");
strcat(buffer, cnumber);
//向mysql发送命令
int ret = mysql_query(mysql, buffer);
if (ret == 0)
{
printf("mysql_query ok\n");
}
else
{
printf("mysql_query error:%s\n", mysql_error(mysql));
}
//从mysql句柄中获取列数
//int num = mysql_field_count(mysql);
//获取结果集
res = mysql_store_result(mysql);
if (res == NULL)
{
printf("mysql_store_result error: %s\n", mysql_error(mysql));
system("pause");
return -1;
}
//从结果集中获取列数
int num = mysql_num_fields(res);
//获取表头信息
field = mysql_fetch_fields(res);
if (field == NULL)
{
printf("mysql_fetch_fields error: %s\n", mysql_error(mysql));
}
else
{
for (int i = 0; i < num; i++)
{
printf("%s\t", field[i].name);//my_field[i].name表示列名
}
printf("\n");
}
//从结果集中获取每一行记录
while (row = mysql_fetch_row(res))
{
for (int i = 0; i < num; i++)//打印每一行记录
{
printf("%s\t", row[i]);
}
printf("\n");
}
//释放结果集
mysql_free_result(res);
printf("继续查询输入1，返回菜单输入0\n");
scanf("%d", &iden);
} while (iden);
return 0;
}
原文地址：https://blog.csdn.net/2401_85919417/article/details/142929876
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