Qt连接SQLServer的问题

[sjyzhxw]

#include <QtCore/QCoreApplication>
#include <QtSql/QSqlDatabase>
#include <QtSql>
#include <QStringList>
#include <QDebug>

struct Student
{
    QString id;
    QString name;
    QString sex;
};


int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QSqlDatabase db=QSqlDatabase::addDatabase("QODBC");


    QString dsn = QString::fromLocal8Bit("DRIVER={SQL SERVER};SERVER=127.0.0.1;DATABASE=mydb");
    db.setDatabaseName(dsn);
    db.setUserName("admin");
    db.setPassword("123456");
    if(db.open()) {
        qDebug()<<"OK!";
    }
    else{
        qDebug()<<"Error!";
    }


    QSqlQuery query(db);
    query.exec("select * from NewStudent");

    QSqlError error=query.lastError();
    qDebug()<<error.number();

    if(!query.isValid()){
        qDebug()<<"Invalid!";
    }

    while(query.next()){
        Student student;

        student.id=query.value(0).toString();
        student.name=query.value(1).toString();
        student.sex=query.value(2).toString();

        qDebug()<<"ID: "<<student.id<<" Name: "<<student.name<<" Sex: "<<student.sex;
    }


    return a.exec();
}

输出了invalid

[xxq123321]

query.next()调用前，query.value数据是没有数据的

[sjyzhxw]

Java风格迭代器用不惯啊。。。
[Quote=引用 1 楼 的回复:]
query.next()调用前，query.value数据是没有数据的
[/Quote]