qt平台连接数据库，实现用户登陆注册代码

在 Qt 平台上连接数据库并实现用户登录注册的代码如下：

首先，在 Qt 项目中添加需要的库文件，包括 QtSql 和 QSqlDatabase。

#include <QtSql>

然后，连接数据库。我们使用 SQLite 数据库，连接代码如下：

QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("myDatabase.db"); // 数据库名称
if (!db.open()) {
    qDebug() << "Failed to open database!";
    return;
}

接下来，定义一个用户类，包含用户名和密码两个属性：

class User {
public:
    QString username;
    QString password;
};

实现用户注册功能：

void registerUser(User user) {
    QSqlQuery query;
    query.prepare("INSERT INTO users (username, password) VALUES (:username, :password)");
    query.bindValue(":username", user.username);
    query.bindValue(":password", user.password);
    if (!query.exec()) {
        qDebug() << "Failed to register user!";
    } else {
        qDebug() << "User registered successfully!";
    }
}

实现用户登录功能：

bool loginUser(User user) {
    QSqlQuery query;
    query.prepare("SELECT * FROM users WHERE username = :username AND password = :password");
    query.bindValue(":username", user.username);
    query.bindValue(":password", user.password);
    if (!query.exec()) {
        qDebug() << "Failed to login!";
        return false;
    }
    if (query.next()) {
        qDebug() << "User logged in successfully!";
        return true;
    }
    qDebug() << "Username or password is incorrect!";
    return false;
}

完整代码如下：

#include <QtSql>

class User {
public:
    QString username;
    QString password;
};

void registerUser(User user) {
    QSqlQuery query;
    query.prepare("INSERT INTO users (username, password) VALUES (:username, :password)");
    query.bindValue(":username", user.username);
    query.bindValue(":password", user.password);
    if (!query.exec()) {
        qDebug() << "Failed to register user!";
    } else {
        qDebug() << "User registered successfully!";
    }
}

bool loginUser(User user) {
    QSqlQuery query;
    query.prepare("SELECT * FROM users WHERE username = :username AND password = :password");
    query.bindValue(":username", user.username);
    query.bindValue(":password", user.password);
    if (!query.exec()) {
        qDebug() << "Failed to login!";
        return false;
    }
    if (query.next()) {
        qDebug() << "User logged in successfully!";
        return true;
    }
    qDebug() << "Username or password is incorrect!";
    return false;
}

int main() {
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("myDatabase.db"); // 数据库名称
    if (!db.open()) {
        qDebug() << "Failed to open database!";
        return -1;
    }

    User user1;
    user1.username = "user1";
    user1.password = "password1";
    registerUser(user1);

    User user2;
    user2.username = "user2";
    user2.password = "password2";
    registerUser(user2);

    User loginUser1;
    loginUser1.username = "user1";
    loginUser1.password = "password1";
    loginUser(loginUser1);

    User loginUser2;
    loginUser2.username = "user2";
    loginUser2.password = "password3";
    loginUser(loginUser2);

    return 0;
}