Qt embedding MYSQL - c++

Question

This Question has been asked by different people about 3times by QLands: here and carnifrex: here and there. My problem is exactly like carnifrex's: I am trying to compile my application to connect to MYSQL(Mariadb) database without Mariadb installation i.e embedded server but I get this Error Below:
error: undefined reference to 'imp__ZN12QMYSQLDriverC1EP8st_mysqlP7QObject' collect2.exe:-1: error: error: ld returned 1 exit status
Unfortunately, carnifrex was not replied. Here's my Code
main.cpp:
#include "mainwindow.h"
#include <QApplication>
#include <QSql>
#include <QMessageBox>
#include "qsql_mysql.h"
#include <mysql.h>
bool createConnection(QMYSQLDriver *drver)
{
QSqlDatabase db = QSqlDatabase::addDatabase(drver);
db.setHostName("localhost");
db.setDatabaseName("exama");
db.setPort(3306);
db.setUserName("root");
db.setPassword("Adm1n16");
if (!db.open()) {
QMessageBox::warning(0, QObject::tr("Database Error"),
db.lastError().text());
return false;
}
return true;
}
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MYSQL *mysql;
static char *server_options[] = \
{"mysql_test", "--defaults-file = C:/Program Files (x86)/MariaDB 10.1/data/my.cnf", NULL };
int num_elements = (sizeof(server_options) / sizeof(char *)) - 1;
static char *server_groups[] = { "embedded", NULL };
qDebug() << "Loading embedded";
mysql_library_init(num_elements, server_options, server_groups);
mysql = mysql_init(NULL);
mysql_options(mysql, MYSQL_READ_DEFAULT_GROUP, "embedded");
mysql_options(mysql, MYSQL_OPT_USE_EMBEDDED_CONNECTION, NULL);
mysql_real_connect(mysql, NULL,NULL,NULL, "database1", 0,NULL,0);
QMYSQLDriver *drv = new QMYSQLDriver(mysql);
if (!createConnection(drv))
return 1;
MainWindow w;
w.show();
return a.exec();
}
mysqlConnect.pro:
QT+=core gui sql\
widgets \
greaterThan(QT_MAJOR_VERSION, 5): QT += widgets
INCLUDEPATH += "C:\Qt\Qt5.4\5.4\mingw491_32\include\QtSql\5.4.0\QtSql\private"
INCLUDEPATH += "C:\Program Files (x86)\MariaDB 10.1\include\mysql"
QMAKE_LIBDIR += "C:\Program Files (x86)\MariaDB 10.1\lib"
LIBS += -lmysql
TARGET = mySQLConnect
TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
QMAKE_CXXFLAGS+=-std=c++11
The compilation fails at this line in main.cpp:
QMYSQLDriver *drv = new QMYSQLDriver(mysql);
I am using Qt Creator 5.4.0 with MingW 4.9.1 32bit on x64 bit Windows 7 Machine. I will be grateful for any assistance granted.