QSqlQuery .lasterror compile error: invalid use of incomplete type 'class QSqlError'

cdwijs

Hi All,

I'm trying to insert items into a mysql database. As I'm doing things wrong, I get returnvalue false from q.exec(); I would like to know what the error is, so I copied the construction from here:
https://doc.qt.io/qt-5/qsqlquery.html#execBatch
When compiling, I get the following error: invalid use of incomplete type 'class QSqlError'

What is going on?
Cheers,
Cedric

09:06:06: Running steps for project untitled8...
09:06:06: Starting: "C:\Qt\5.10.1\mingw53_32\bin\qmake.exe" C:\Users\crldewijs\Desktop\git\untitled8\untitled8.pro -spec win32-g++ "CONFIG+=debug" "CONFIG+=qml_debug"
Info: creating stash file C:\Users\crldewijs\Desktop\git\build-untitled8-Desktop_Qt_5_10_1_MinGW_32bit-Debug\.qmake.stash
09:06:07: The process "C:\Qt\5.10.1\mingw53_32\bin\qmake.exe" exited normally.
09:06:07: Starting: "C:\Qt\Tools\mingw530_32\bin\mingw32-make.exe" qmake_all
mingw32-make: Nothing to be done for 'qmake_all'.
09:06:08: The process "C:\Qt\Tools\mingw530_32\bin\mingw32-make.exe" exited normally.
09:06:08: Starting: "C:\Qt\Tools\mingw530_32\bin\mingw32-make.exe" 
C:/Qt/Tools/mingw530_32/bin/mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory 'C:/Users/crldewijs/Desktop/git/build-untitled8-Desktop_Qt_5_10_1_MinGW_32bit-Debug'
C:\Qt\5.10.1\mingw53_32\bin\uic.exe ..\untitled8\mainwindow.ui -o ui_mainwindow.h
g++ -c -fno-keep-inline-dllexport -g -std=gnu++11 -Wall -W -Wextra -fexceptions -mthreads -DUNICODE -D_UNICODE -DWIN32 -DQT_DEPRECATED_WARNINGS -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_SQL_LIB -DQT_CORE_LIB -DQT_NEEDS_QMAIN -I..\untitled8 -I. -IC:\Qt\5.10.1\mingw53_32\include -IC:\Qt\5.10.1\mingw53_32\include\QtWidgets -IC:\Qt\5.10.1\mingw53_32\include\QtGui -IC:\Qt\5.10.1\mingw53_32\include\QtANGLE -IC:\Qt\5.10.1\mingw53_32\include\QtSql -IC:\Qt\5.10.1\mingw53_32\include\QtCore -Idebug -I. -IC:\Qt\5.10.1\mingw53_32\mkspecs\win32-g++  -o debug\main.o ..\untitled8\main.cpp
g++ -c -fno-keep-inline-dllexport -g -std=gnu++11 -Wall -W -Wextra -fexceptions -mthreads -DUNICODE -D_UNICODE -DWIN32 -DQT_DEPRECATED_WARNINGS -DQT_QML_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_SQL_LIB -DQT_CORE_LIB -DQT_NEEDS_QMAIN -I..\untitled8 -I. -IC:\Qt\5.10.1\mingw53_32\include -IC:\Qt\5.10.1\mingw53_32\include\QtWidgets -IC:\Qt\5.10.1\mingw53_32\include\QtGui -IC:\Qt\5.10.1\mingw53_32\include\QtANGLE -IC:\Qt\5.10.1\mingw53_32\include\QtSql -IC:\Qt\5.10.1\mingw53_32\include\QtCore -Idebug -I. -IC:\Qt\5.10.1\mingw53_32\mkspecs\win32-g++  -o debug\mainwindow.o ..\untitled8\mainwindow.cpp
..\untitled8\mainwindow.cpp: In constructor 'MainWindow::MainWindow(QWidget*)':
..\untitled8\mainwindow.cpp:17:29: error: invalid use of incomplete type 'class QSqlError'
     qDebug() << q.lastError(); // as per https://doc.qt.io/qt-5/qsqlquery.html#execBatch
                             ^
In file included from C:\Qt\5.10.1\mingw53_32\include\QtSql/QSqlDatabase:1:0,
                 from ..\untitled8\mainwindow.cpp:7:
C:\Qt\5.10.1\mingw53_32\include\QtSql/qsqldatabase.h:49:7: note: forward declaration of 'class QSqlError'
 class QSqlError;
       ^
Makefile.Debug:822: recipe for target 'debug/mainwindow.o' failed
mingw32-make[1]: Leaving directory 'C:/Users/crldewijs/Desktop/git/build-untitled8-Desktop_Qt_5_10_1_MinGW_32bit-Debug'
mingw32-make[1]: *** [debug/mainwindow.o] Error 1
Makefile:36: recipe for target 'debug' failed
mingw32-make: *** [debug] Error 2
09:06:13: The process "C:\Qt\Tools\mingw530_32\bin\mingw32-make.exe" exited with code 2.
Error while building/deploying project untitled8 (kit: Desktop Qt 5.10.1 MinGW 32bit)
When executing step "Make"
09:06:13: Elapsed time: 00:08.

My program:

#-------------------------------------------------
#
# Project created by QtCreator 2018-07-23T08:59:04
#
#-------------------------------------------------

QT       += core gui sql

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = untitled8
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0


SOURCES += \
        main.cpp \
        mainwindow.cpp

HEADERS += \
        mainwindow.h

FORMS += \
        mainwindow.ui

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QDebug>
#include <QtWidgets>
#include <QWidget>
#include <QSqlDatabase>
#include <QSqlQuery>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QSqlQuery q;
    qDebug() << q.lastError(); // as per https://doc.qt.io/qt-5/qsqlquery.html#execBatch
}

MainWindow::~MainWindow()
{
    delete ui;
}

My versions:
Qt 5.10.1 mingw53_32
Windows 7 Enterprise SP1

raven-worx

@cdwijs
try adding #include <QSqlError>
;)

cdwijs

@raven-worx said in QSqlQuery .lasterror compile error: invalid use of incomplete type 'class QSqlError':

#include <QSqlError>

That works, Thanks.