SQL

[matobodo]

I have a Sql class:
sql.h
@#ifndef SQL_H
#define SQL_H

#include <QObject>
#include <QStringList>
#include <QtSql>
#include <QDebug>

class Sql : public QObject
{
Q_OBJECT
public:
QSqlDatabase db;

explicit Sql(QObject *parent = 0);
~Sql();
bool connect();
QStringList getUsernames();
QStringList getPasswords();
QStringList getUserdata(QString username);

private:
};

#endif // SQL_H
@
sql.cpp
@#include "sql.h"

Sql::Sql(QObject *parent) :
QObject(parent)
{
}

Sql::~Sql()
{
db.close();
QSqlDatabase::removeDatabase("database");
}

bool Sql::connect()
{
QString serverName = "LOCALHOST\SQLEXPRESS";
QString dbName = "cechosped";

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

db.setConnectOptions();

QString dsn = QString("DRIVER={SQL Native Client};SERVER=%1;DATABASE=%2;Trusted_Connection=Yes").arg(serverName).arg(dbName);

db.setDatabaseName(dsn);

if (db.open()){
return true;
}else{
return false;
}

}

QStringList Sql::getUsernames()
{
QSqlQuery *qry = new QSqlQuery(db);
QStringList list;
list << "0";
if (qry->exec("SELECT [username] FROM [cechosped].[dbo].[users]")) {
list.clear();
while (qry->next()) list << qry->value(0).toString();
}
return list;
}

QStringList Sql::getPasswords()
{
QSqlQuery *qry = new QSqlQuery(db);
QStringList list;
list << "0";
if (qry->exec("SELECT [password] FROM [cechosped].[dbo].[users]")) {
list.clear();
while (qry->next()) list << qry->value(0).toString();
}
return list;
}
@

In other class i have this:
@Sql *sql = new Sql;
if (sql->connect()) {
usernames = sql->getUsernames();
passwords = sql->getPasswords();
if (usernames[0] == "0" || passwords[0] == "0") {
// QMessageBox
} else {
// if everything ok do something ...
}
} else {
// QMessageBox
}
delete sql;@
When this part of code is executed this application output shows:
QSqlDatabasePrivate::removeDatabase: connection 'database' is still in use, all queries will cease to work.

How can i fix it?

[hskoglund]

Hi, I think the problem is your CSqlQuery objects, they're never deleted, that's why QSqlDatabasePrivate complains.
So, test by adding a delete qry at the end of your getUsernames() and getPasswords() functions.

[dheerendra]

You can look at the similar posts "here":https://qt-project.org/forums/viewthread/16417

[matobodo]

i have added
@delete qry;@
it show the same output

[hskoglund]

Sorry forgot about the db instance, Dheerendra thanks for the link.

So what I mean, the db instance needs to be deleted before calling removeDatabase(), but since your db variable isn't a pointer, I think instead just try removing this line:
@
QSqlDatabase::removeDatabase("database");
@