QT-使用MySQL数据库

配置

首先在.pro文件中添加sql

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greaterThan(QT_MAJOR_VERSION, 4): QT += widgets sql

引用下列头文件

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#include<QSqlDatabase>
#include<QSqlError>
#include<QSqlQuery>

构建项目， 在生成的形如build-Database-Desktop_Qt_5_9_0_MinGW_32bit-Debug/debug目录下添加libmysql.dll文件。

初始化

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QSqlDatabase db;


db = QSqlDatabase::addDatabase("QMYSQL3");
db.setHostName("127.0.0.1");  //连接本地主机
db.setPort(3306);
db.setDatabaseName("scores");
db.setUserName("root");
db.setPassword("*******");

bool ok = db.open();
if (ok){
    QMessageBox::information(this, "infor", "link success");
}
else {
    QMessageBox::information(this, "infor", "link failed");
    qDebug()<<"error open database because"<<db.lastError().text();
}

执行SQL语句

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QSqlQuery query;
QString sql=QString("insert into fam (name,address,age,gender) values ('%1','%2','%3','%4')").arg(name).arg(addres).arg(age).arg(gender);
query.exec(sql);

QString sql="select * from fam";
QSqlQuery query;
query.exec(sql);
ui->textEdit->clear();
while(query.next())
{
    ui->textEdit->insertPlainText(QString::number(query.value(0).toInt())+' ');
    ui->textEdit->insertPlainText(QString(query.value(1).toString())+' ');
    ui->textEdit->insertPlainText(QString(query.value(2).toString())+' ');
    ui->textEdit->insertPlainText(QString::number(query.value(3).toInt())+' ');
    ui->textEdit->insertPlainText(QString(query.value(4).toString()+="\n"));
}

事务

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db.transaction();
if(query.exec(sql))
{
    db.commit(); 
}
else
{
    db.rollback();
    QMessageBox::information(this,"connection info","update failed!");
}

错误

db.lastError().text()