qt连接数据库Sqlite

#include <QCoreApplication>
#include <QDebug>
#include <QSqlDatabase>
#include <QSqlQuery>
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("student.db");
    if(!db.open())
    {
        qDebug() << "open err";
    }
    else
    {
        qDebug() << "database is ok";
    }
    QSqlQuery query(db);
    bool isok = query.exec("create table stud(id int primary key,name varchar(20))");
    query.exec("insert into stud values(111,'liming')");
    query.exec("insert into stud values(102,'li')");
    query.exec("insert into stud values(103,'lisi')");
    query.exec("insert into stud values(105,'zhangsan')");

    if(!isok)
    {
        qDebug() << "table err";
    }
    else
    {
        qDebug() << "table is ok";
    }

    query.exec("select * from stud");
    while(query.next())
    {
        qDebug() << "id:"<<query.value().toInt()<<"name:"<<query.value().toString();
    }
    return a.exec();
}

if(QSqlDatabase::contains("myconn"))
    {
        db = QSqlDatabase::database("myconn");
    }else
    {

        db = QSqlDatabase::addDatabase("QSQLITE","myconn");
    }
    db.setDatabaseName("sqlite.db");
    bool ok = db.open();

    if(ok)
    {
        return true;
    }else
    {
        return false;
    }