文章目录
0. Mysql安装与开发环境配置
1. win10 Navicat 连接虚拟机的MySQL需要关闭防火墙
- 查看防火墙端口开放的情况：
service firewalld status
- 关闭防火墙：
systemctl stop firewalld
2. 由于找不到libmysql.dIl, 无法继续执行代码。重新安装程序可能会解决此问题。
将D:\MySQL\mysql-8.0.33-winx64\lib目录下的libmysql.dll拷贝到E:\Code\VS2022\student_manager\student_manager。
3. 测试连接数据库，并插入数据
#include <iostream>
#include <mysql.h>
#include <string>
using namespace std;
const char* host = "127.0.0.1";
const char* user = "root";
const char* pw = "111111";
const char* database_name = "student_manager";
const int port = 3306;
typedef struct Student {
int student_id;
string student_name;
string class_id;
}Student;
int main() {
MYSQL* con = mysql_init(NULL);
// 设置字符编码
mysql_options(con, MYSQL_SET_CHARSET_NAME, "GBK");
if (!mysql_real_connect(con, host, user, pw, database_name, port, NULL, 0)) {
fprintf(stderr, "Failed to connect to database : Error:%s\n", mysql_errno(con));
return -1;
}
Student stu = {
1001, "吴彦祖", "计算机2班" };
char sql[256];
sprintf_s(sql, "insert into students(student_id, student_name, class_id) values(%d, '%s', '%s');",
stu.student_id, stu.student_name.c_str(), stu.class_id.c_str());
if (mysql_query(con, sql)) {
fprintf(stderr, "Failed to insert data : Error:%s\n", mysql_errno(con));
return -1;
}
mysql_close(con);
return 0;
}
4. C++封装MySQL增删改查操作
// StudentManager.h
#ifndef STUDENTMANAGER_H
#define STUDENTMANAGER_H
#include <mysql.h>
#include <string>
#include <vector>
#include <iostream>
using namespace std;
typedef struct Student {
int student_id;
string student_name;
string class_id;
}Student;
class StudentManager {
StudentManager();
~StudentManager();
public: // 单例模式：只创建一个实体，即只创建一个学生管理类即可
static StudentManager* GetInstance() {
static StudentManager StudentManager;
return &StudentManager;
}
public:
bool insert_student(Student& stu);
bool update_student(Student& stu);
bool delete_student(int student_id);
vector<Student> get_students(string condition = "");
private:
MYSQL* con;
const char* host = "127.0.0.1";
const char* user = "root";
const char* pw = "111111";
const char* database_name = "student_manager";
const int port = 3306;
};
#endif // STUDENTMANAGER_H
// StudentManager.cpp
#include "StudentManager.h"
StudentManager::StudentManager() {
con = mysql_init(NULL);
// 设置字符编码
mysql_options(con, MYSQL_SET_CHARSET_NAME, "GBK");
if (!mysql_real_connect(con, host, user, pw, database_name, port, NULL, 0)) {
fprintf(stderr, "Failed to connect to database : Error:%s\n", mysql_errno(con));
exit(1);
}
}
StudentManager::~StudentManager() {
mysql_close(con);
}
bool StudentManager::insert_student(Student& stu) {
char sql[256];
sprintf_s(sql, "INSERT INTO students(student_id, student_name, class_id) values(%d, '%s', '%s');",
stu.student_id, stu.student_name.c_str(), stu.class_id.c_str());
if (mysql_query(con, sql)) {
fprintf(stderr, "Failed to insert data : Error:%s\n", mysql_errno(con));
return false;
}
return true;
}
bool StudentManager::update_student(Student& stu) {
char sql[256];
sprintf_s(sql, "UPDATE students SET student_name = '%s', class_id = '%s' WHERE student_id = %d",
stu.student_name.c_str(), stu.class_id.c_str(), stu.student_id);
if (mysql_query(con, sql)) {
fprintf(stderr, "Failed to update data : Error:%s\n", mysql_errno(con));
return false;
}
return true;
}
bool StudentManager::delete_student(int student_id) {
char sql[256];
sprintf_s(sql, "DELETE FROM students WHERE student_id = %d", student_id);
if (mysql_query(con, sql)) {
fprintf(stderr, "Failed to delete data : Error:%s\n", mysql_errno(con));
return false;
}
return true;
}
vector<Student> StudentManager::get_students(string condition) {
vector<Student> stuList;
char sql[256];
sprintf_s(sql, "SELECT * FROM students %s", condition.c_str());
if (mysql_query(con, sql)) {
fprintf(stderr, "Failed to select data : Error:%s\n", mysql_errno(con));
return {
};
}
MYSQL_RES* res = mysql_store_result(con);
MYSQL_ROW row;
while (row = mysql_fetch_row(res)) {
Student stu;
stu.student_id = atoi(row[0]);
stu.student_name = row[1];
stu.class_id = row[2];
stuList.emplace_back(stu);
}
return stuList;
}
// main.cpp
#include "StudentManager.h"
int main() {
Student stu{
999, "彭于晏", "网工1班"};
StudentManager::GetInstance()->insert_student(stu);
Student stu{
999, "彭于晏", "网工3班" };
StudentManager::GetInstance()->update_student(stu);
StudentManager::GetInstance()->delete_student(1000);
vector<Student> ret = StudentManager::GetInstance()->get_students();
for (auto& t : ret) {
cout << t.student_id << " " << t.student_name << " " << t.class_id << endl;
}
return 0;
}
// main.cpp
#include "StudentManager.h"
int main() {
StudentManager* studentManager = StudentManager::GetInstance();
Student stu1{
1009, "彭于晏", "网工1班"};
studentManager->insert_student(stu1);
Student stu2{
999, "胡歌", "网工3班" };
studentManager->update_student(stu2);
studentManager->delete_student(1001);
vector<Student> ret = studentManager->get_students();
for (auto& t : ret) {
cout << t.student_id << " " << t.student_name << " " << t.class_id << endl;
}
return 0;
}