Qt之自带的数据库QSQLITE（很具体的一个例子）

database.h

#ifndef DATABASE_H
#define DATABASE_H
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

class DataBase
{
public:
    bool createConnection();  //创建一个连接
    bool createTable();       //创建数据库表
    bool insert();            //出入数据
    bool queryAll();          //查询所有信息
    bool updateById(int id);  //更新
    bool deleteById(int id);  //删除
    bool sortById();          //排序
};

#endif // DATABASE_H

database.cpp

#include "database.h"

//建立一个数据库连接
bool DataBase::createConnection()
{
    //以后就可以用"sqlite1"与数据库进行连接了
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE", "sqlite1");
    db.setDatabaseName(".//qtDb.db");
    if( !db.open())
    {
        qDebug() << "无法建立数据库连接";
        return false;
    }
    return true;
}

//创建数据库表
bool DataBase::createTable()
{
    QSqlDatabase db = QSqlDatabase::database("sqlite1"); //建立数据库连接
    QSqlQuery query(db);
    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");
        return true;
    }
    else
    {
        qDebug() << QObject::tr("数据库表创建失败！\n");
        return false;
    }
}

//向数据库中插入记录
bool DataBase::insert()
{
    QSqlDatabase db = QSqlDatabase::database("sqlite1"); //建立数据库连接
    QSqlQuery query(db);
    query.prepare("insert into automobil values(?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");

    long records = 10;
    for(int i=0; i0, 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);

        bool success=query.exec();
        if(!success)
        {
            QSqlError lastError = query.lastError();
            qDebug() << lastError.driverText() << QString(QObject::tr("插入失败"));
            return false;
        }
    }
    return true;
}

//查询所有信息
bool DataBase::queryAll()
{
    QSqlDatabase db = QSqlDatabase::database("sqlite1"); //建立数据库连接
    QSqlQuery query(db);
    query.exec("select * from automobil");
    QSqlRecord rec = query.record();
    qDebug() << QObject::tr("automobil表字段数：" ) << rec.count();

    while(query.next())
    {
        for(int index = 0; index < 10; index++)
            qDebug() << query.value(index) << " ";
        qDebug() << "\n";
    }
}

//根据ID删除记录
bool DataBase::deleteById(int id)
{
    QSqlDatabase db = QSqlDatabase::database("sqlite1"); //建立数据库连接
    QSqlQuery query(db);
    query.prepare(QString("delete from automobil where id = %1").arg(id));
    if(!query.exec())
    {
        qDebug() << "删除记录失败！";
        return false;
    }
    return true;
}

//根据ID更新记录
bool DataBase::updateById(int id)
{
    QSqlDatabase db = QSqlDatabase::database("sqlite1"); //建立数据库连接
    QSqlQuery query(db);
    query.prepare(QString("update automobil set attribute=?,type=?,"
                             "kind=?, nation=?,"
                             "carnumber=?, elevaltor=?,"
                             "distance=?, oil=?,"
                             "temperature=? where id=%1").arg(id));

     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);

     bool success=query.exec();
     if(!success)
     {
          QSqlError lastError = query.lastError();
          qDebug() << lastError.driverText() << QString(QObject::tr("更新失败"));
     }
    return true;
}

//排序
bool DataBase::sortById()
{
    QSqlDatabase db = QSqlDatabase::database("sqlite1"); //建立数据库连接
    QSqlQuery query(db);
    bool success=query.exec("select * from automobil order by id desc");
    if(success)
    {
        qDebug() << QObject::tr("排序成功");
        return true;
    }
    else
    {
        qDebug() << QObject::tr("排序失败！");
        return false;
    }
}

main.cpp

#include 
#include "database.h"

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QTextCodec::setCodecForLocale(QTextCodec::codecForLocale());

    DataBase d;
    d.createConnection();  //创建连接
    //d.createTable();
    //d.insert();
    d.queryAll();          //已经完成过createTable(), insert(), 现在进行查询

    return 0;
}

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运行结果

项目名称为”sqlex”，然后就可以在与当前项目同一级目录下的“build-SQLEx-Desktop_Qt_5_7_0_MinGW_32bit-Debug”中可以看到qtDb.db数据库文件，该数据库可以用软件SQLite直接打开

项目名称为”sqlex”，然后就可以在与当前项目同一级目录下的“build-SQLEx-Desktop_Qt_5_7_0_MinGW_32bit-Debug”中可以看到qtDb.db数据库文件，该数据库可以用软件SQLite直接打开