#include <QCoreApplication>
...
int main(int argc, char *argv[])
{
    ...
    QCoreApplication app(argc, argv);
    ...
    return app.exec();
}

TEMPLATE = app
TARGET = tsreader
DEPENDPATH += .
INCLUDEPATH += .
CONFIG += console
QT += xml sql core
QT -=  gui
HEADERS += tsreader.h dbconnect.h ticket.h
SOURCES += main.cpp

#include <QtSql>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>
#include <QString>
#include <QDebug>



//=====================================================
//        Установим соединение с БД
//=====================================================
bool OpenDb(QString dbname)
{
  bool ok;
  
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName(dbname);
    ok = db.open();
    qDebug() << db << "\n\r";
    if (!ok)
    {
        qDebug() << "OpenDb: " << db.lastError().text() << "\n\r";
    }
    return ok;
}