CODEWITHSUNDEEP
c++sql-serverqt
Nour
Nour

Reputation: 61

How to bound QString to QSqlQuery that call procedure which output varchar?

I managed to bound integer values to this type of queries but I couldn't manage to bound QString.

I keep getting empty QVariant. However, in Sql server I get the value I wanted to get.

The procedure will output VARCHAR(max)

qDebug() << query.prepare("{call dbo.p_test(?)}");
query.bindValue(0, QString(""), QSql::Out);
qDebug() << query.exec();
qDebug() << query.boundValue(0);

I have tried binding:

''
""
QString()
QString("")
QVariant()
QVariant(QVariant::String)

How I should bind the value to be able to bound correctly?

I am using Qt 4.8.4

P.S. When doing it this way I can get the string value I wanted.

query.exec("DECLARE @r VARCHAR(MAX); EXEC dbo.p_test @r OUTPUT; SELECT @r");
query.first();
qDebug()<<query.value(0);

updates

Here how it gets really weirdo

  1. I changed QSql::Out to QSql::InOut.
  2. I edited the procedure so it will insert the value in a table.
  3. I changed the bind command to query.bindValue(0, QString("1234567"), QSql::InOut);

I checked for the value I had passed in sql server and it was

'1234567'

I checked the value I got from qDebug()<<query.boundValue(0) and it was

QVariant(QString, "1234")

no matter that my procedure should return

'7654321'

CREATE PROCEDURE dbo.p_test
    @rez varchar(max)
BEGIN
    INSERT INTO test VALUES(@rez)
    SET @rez = '7654321';
END;

Upvotes: 2

Views: 877

Answers (2)

Nour
Nour

Reputation: 61

As mentioned in the comments

This bug is present in Qt4 and is fixed in Qt5 (hence my question): bugreports.qt.io/browse/QTBUG-18435 – jbh Mar 27 at 9:54

it is really a bug, no way to get around it in Qt4.

Qt4 is too buggy, I have found another 3 bugs today -_- unlucky me.

Upvotes: 1

Mohammad Kanan
Mohammad Kanan

Reputation: 4592

I think you have to properly format the output,

qDebug() << query.boundValue(0).toString();

or:

qDebug() << query.boundValue(0).toString().toUtf8().data();

if you have more than bounded values, then you can use QSqlQuery::boundValues() with a list:

list.at(i).toString().toUtf8().data()

Upvotes: 1

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