数据库

2019-11-08 20:07:30

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//例子1#include <QCoreapplication>#include <QTextCodec>#include <QSqlDatabase>#include <QSqlQuery>#include <QTime>#include <QSqlError>#include <QtDebug>#include <QSqlDriver>#include <QSqlRecord>int main(int argc, char *argv[]){ QCoreApplication a(argc, argv); QTextCodec::setCodecForLocale(QTextCodec::codecForLocale()); QSqlDatabase db =QSqlDatabase::addDatabase("QSQLITE"); //使用QSQLITE驱动 db.setHostName("easybook-3313b0"); //设置数据库主机名 db.setDatabaseName("qtDB.db"); //设置数据库名 db.setUserName("zhouhejun"); //设置数据库用户名 db.setPassWord("123456"); //设置数据库密码 db.open(); //打开连接 //创建数据库表 QSqlQuery query; 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("数据库表创建成功！/n"); else qDebug()<<QObject::tr("数据库表创建失败！/n"); //查询 query.exec("select * from automobil"); QSqlRecord rec = query.record(); //查询返回的记录 qDebug() << QObject::tr("automobil表字段数：" )<< rec.count(); //插入记录 QTime t; t.start(); query.prepare("insert into automobil values(?,?,?,?,?,?,?,?,?,?)"); long records=100; for(int i=0;i<records;i++) { //设置对应位置的参数 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); //执行插入语句 success=query.exec(); if(!success) { QSqlError lastError=query.lastError(); qDebug()<<lastError.driverText()<<QString(QObject::tr("插入失败")); } } qDebug()<<QObject::tr("插入 %1 条记录，耗时：%2 ms").arg(records).arg(t.elapsed()); //排序 t.restart(); success=query.exec("select * from automobil order by id desc"); 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(); for(int i=0;i<records;i++) { query.clear(); query.prepare(QString("update automobil set attribute=?,type=?," "kind=?,nation=?," "carnumber=?,elevaltor=?," "distance=?,oil=?," "temperature=? where id=%1").arg(i)); 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(); 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(); query.exec("delete from automobil where id=15"); qDebug()<<QObject::tr("删除一条记录，耗时：%1 ms").arg(t.elapsed()); return 0; //return a.exec();}

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