SQLite数据库的 初级写法 和 中级写法的比较

//初级形态bool opendatabase(){    QSqlDatabase mydb=QSqlDatabase::addDatabase("QSQLITE");    mydb.setDatabaseName(MydbLocal);//平时debug正常用    //mydb.setDatabaseName("./employee.db");//release用
    if(mydb.open())    {        qDebug()<<"open success";        return true;    }    else    {        qDebug()<<"open failed";        return false;    }}

// 打开数据库  使用<SQL_lite>bool OpenDatabase(){    QSqlDatabase mydb;
    if (QSqlDatabase::contains(databaseName)) {          //打开了数据库         mydb = QSqlDatabase::database(databaseName);    }    else {                                              //若数据库不存在，则会直接创建        mydb = QSqlDatabase::addDatabase("QSQLITE");        //设置sql库名称        mydb.setDatabaseName(MydbLocal+ "/" + databaseName + ".db");        qDebug() << QCoreApplication::applicationDirPath() << mydb.databaseName();    }
    //是否打开失败    if(!mydb.open())    {        //提示错误        qDebug()<<"open false";        QMessageBox::warning(0, QObject::tr("Database Error"), mydb.lastError().text());        //提示框        return false;    }
    //创建表    QSqlQuery query;    bool finish = query.exec(QString("create table %1 (name varchar, number varchar, departments varchar,class varchar, EnterTime varchar, GPA varchar, password varchar)").arg(datatableName));    if (finish == true) {        //插入管理员信息        query.exec(QString("insert into %1 values ('admin','201010','人事部', '人事经理' ,'2010','5.3','admin')").arg(datatableName));        //虚拟员工信息        query.exec(QString("insert into %1 values ('abc','201103','综合办', '职员' ,'2011','4.7','123')").arg(datatableName));        query.exec(QString("insert into %1 values ('ablke','201711','财务部', '财务部长' ,'2016','3.3','456')").arg(datatableName));
        return true;   //新建数据库成功    }    else {        QSqlError lastError = query.lastError();        qDebug()<<lastError;        QString err = lastError.driverText();        return false;    }
    return true;}