标签：占位符   insert   定时器   return   drive   let   open()   art   rom   

include "mainwindow.h"

include

include

include

include

include

include

include

include

include

int main(int argc, char *argv[])
{
//连接数据库

QSqlDatabase db =QSqlDatabase::addDatabase("QSQLITE");
db.setHostName("easybook-3313b0");          //设置数据库主机名
db.setDatabaseName("qtDB.db");              //设置数据库名
db.setUserName("ly");                //设置数据库用户名
db.setPassword("123456");                   //设置数据库密码
db.open();                             		//打开
//创建连接
QSqlQuery query;
//创建数据表结构
bool success = query.exec("create table automobil(id int primary key,attribute varchar,type varchar,kind varchar,nation int,carnumber int,elevaltor int,distance int,oil int,temperature int)");
if(success)
{
    qDebug()<<QObject::tr("数据库创建成功！\n");
}
else
{
    qDebug()<<QObject::tr("error!\n");
}
//查询
query.exec("select * from automobil");//执行sql语句
QSqlRecord rec = query.record();//获取返回结果
qDebug() << QObject::tr("automobil表字段数：" )<< rec.count();//输出结果

//插入记录
QTime t; //定时器
t.start(); //启动
query.prepare("insert into automobil values(?,?,?,?,?,?,?,?,?,?)");//占位符

long records=100;
for(int i=0;i<records;i++)
{
    //绑定插入数据
    query.bindValue(0,i);
    query.bindValue(1,"四轮");
    query.bindValue(2,"轿车");
    query.bindValue(3,"富康");
    query.bindValue(4,rand()%100);
    query.bindValue(5,rand()%10000);
    query.bindValue(6,rand()%300);
    query.bindValue(7,rand()%200000);
    query.bindValue(8,rand()%52);
    query.bindValue(9,rand()%100);

    success=query.exec();//在query中插入值
    if(!success)
    {
        QSqlError lastError=query.lastError();
        qDebug()<<lastError.driverText()<<QString(QObject::tr("插入失败"));
    }
}
// 计时及统计
qDebug()<<QObject::tr("插入 %1 条记录，耗时：%2 ms").arg(records).arg(t.elapsed());//

//排序
t.restart();//重新计时
success=query.exec("select * from automobil order by id desc");//按ID排序
if(success)
    qDebug()<<QObject::tr("排序 %1 条记录，耗时：%2 ms").arg(records).arg(t.elapsed());
else
    qDebug()<<QObject::tr("排序失败！");

//更新记录
t.restart();//重新计时
for(int i=0;i<records;i++)
{
    query.clear();//清除原有事务
    query.prepare(QString("update automobil set attribute=?,type=?,"
                          "kind=?,nation=?,"
                          "carnumber=?,elevaltor=?,"
                          "distance=?,oil=?,"
                          "temperature=? where id=%1").arg(i));//占位


    query.bindValue(0,"四轮");
    query.bindValue(1,"轿车");
    query.bindValue(2,"富康");
    query.bindValue(3,rand()%100);
    query.bindValue(4,rand()%10000);
    query.bindValue(5,rand()%300);
    query.bindValue(6,rand()%200000);
    query.bindValue(7,rand()%52);
    query.bindValue(8,rand()%100);

    success=query.exec();//执行
    if(!success)
    {
        QSqlError lastError=query.lastError();
        qDebug()<<lastError.driverText()<<QString(QObject::tr("更新失败"));
    }
}
qDebug()<<QObject::tr("更新 %1 条记录，耗时：%2 ms").arg(records).arg(t.elapsed());


//删除
    t.restart();//重新计时
    query.exec("delete from automobil where id=15");
    qDebug()<<QObject::tr("删除一条记录，耗时：%1 ms").arg(t.elapsed());

QApplication a(argc, argv);
MainWindow w;
w.show();

return a.exec();

}

Qt 数据库基本使用 -QSQLITE

标签：占位符   insert   定时器   return   drive   let   open()   art   rom   

原文地址：https://www.cnblogs.com/xiangyangcao/p/13352466.html