Selecting data from mysql using qt?
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Maybe an "#include <QVariant>" is missing at the top?
T.
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Why not just
@#include <QtCore>
#include <QtSql>@and not worry about every single class you use?
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That can be a solution only when you're testing something. So, in this case, I agree with you, let's avoid such worries.
But if your project grows up, it's better to include what's needed, otherwise your compilation time can increase a lot.
T.
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i add #include <QVariant>
now it is saying
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QSqlQuery::exec: database not open
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Try to use QSqlQuery::lastError() for find problem
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what is the problem now in my code why it is not opening database?
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Did you leave
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//bool ok = db.open();
@commented?
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well i changed my code to this and added lastError as well
@
#include <QApplication>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>
#include <QDebug>
#include <QString>
#include <QVariant>
//#include <QtCore>
//#include <QtSql>
//#include "../connection.h"
#include "db.h"int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL"); db.setDatabaseName("testTwo"); db.setUserName("root"); db.setPassword(""); db.setHostName("localhost"); //bool ok = db.open(); QSqlQuery query; query.exec("SELECT firstname,lastname FROM testTable"); while(query.next()) { QString firstName = query.value(0).toString(); QString secondName = query.value(1).toString(); qDebug() << "First Name: " << firstName << "Last Name:" << secondName; qDebug() << db.lastError(); } return a.exec();
}
@it still says QSqlQuery::exec: database not open
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it is still as commented
[quote author="Antonio Di Monaco" date="1286818410"]Did you leave@
//bool ok = db.open();
@commented?[/quote]
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Try uncomment line 23
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i uncomment line 23 and comment everything below line 23 then it just says
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Starting /home/zafar/c++/dbExample-build-desktop/dbExample...
@and stucks there
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OH! You use SQL code before
a.exec()
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Are you sure?Create standart QT GUI application and wrote sql code in mainwindow module.
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i am new to qt. how can i create Qt Gui App and do you mean i should write sql code in mainwindow.h file?
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right now i have three files. db.h, db,cpp and main.cpp
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Run QT Creator.
Use menu File/new file or project.
Select QT Gui application.
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and select SQL checkbox
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and write sql code in MainWindow.cpp
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and see SQL Example please -
well i tried "File/new file or project and select qt gui app" but i ddint find any sql checkbox anywhere in creating new project
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no coments...
How can I send you screenshot? -
you can add pictures here as screenshots or if you want my email address i ll give you that as well for screenshots
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anyone who can help?
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!http://hin.dp.ua/files/down/qt_scr.PNG(my screenshot)!
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