如何在 SQL Server Express 表中保存 QTime 并读取它? [英] How to save QTime in SQL Server Express table and read it back?

问题描述

我在 SQL Server Express 中有一个表，其中包含字段 name varchar(10) 和 timeVar time，我想保存 QTime 的值time 字段中的 code> 变量.

I have a table in SQL Server Express with fields name varchar(10) and timeVar time and I want to save the value of a QTime variable in the time field.

这是我尝试过的:

QTime time = QTime::currentTime();
QString timeString = time.toString("hh:mm:ss");
QString query = QString("insert into timeHold(name,timeVar) values ('ABC','%2')").arg(timeString);

qry->prepare(query);
qry->exec();

但是，我得到 QSqlQuery::value: notlocated on a valid record.

当我从 SQL Server Management Studio 向表中插入值时，insert into timeHold values('XYZ', '12:17:35') 完美运行.但令我惊讶的是，当我尝试从管理工作室读取存储在表中的值时，我能够获取名称字段，但不能获取时间字段.

When I insert values into the table from SQL Server Management Studio, insert into timeHold values('XYZ', '12:17:35') works perfectly. To my surprise though, when I have tried reading the values stored in the table from the management studio, I was able to get the name field, but not time field.

这是我用来从表中读取值的代码:

Here is the code I use to read values from the table:

QString query = QString("select * from timeHold");

qry->prepare(query);
qry->exec();
qry->first();

int noOfRecords = qry->numRowsAffected();

do {
    qDebug() << qry->value(0).toString();
    qDebug() << qry->value(1).toString();
} while (qry->next());

代码产生以下输出:

"ABC"
"\u0017"
"world"
"\u000B"
"Mama"
"\u000B"
"Gerama"
"\u000B"

我怎样才能让它发挥作用?

How can I make it work?

推荐答案

对于保存故事，我会说 arg 方法不起作用，因为您要求 %2 但只有一个元素可以替换

For the saving story , I would say the arg method does not work because you ask for %2 but there is only one element to substitute

   query = QString("insert into timeHold(name,timeVar) values ('ABC','%2')").arg(timeString);

我觉得应该是

query =  QString("insert into timeHold(name,timeVar) values ('ABC','%1')").arg(timeString);

对于从数据库中检索，要么是因为插入或读取时必须指定格式

For retrieving from the DB, it's either because you have to specify the format when inserting or when reading

这篇关于如何在 SQL Server Express 表中保存 QTime 并读取它?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！