QSqlDatabase::removeDatabase(QSqlDatabase::connectionName());
QSqlDatabase::close();

 {
     QSqlDatabase db = QSqlDatabase::database("sales");
     QSqlQuery query("SELECT NAME, DOB FROM EMPLOYEES", db);
 }
 // Both "db" and "query" are destroyed because they are out of scope
 QSqlDatabase::removeDatabase("sales"); // correct

QSqlDatabase::close();
QSqlDatabase::~QSqlDatabase();
QSqlDatabase::removeDatabase();

void QSQLite2Driver::close()
{
    if (isOpen()) {
        sqlite_close(d->access);
        d->access = 0;
        setOpen(false);
        setOpenError(false);
    }
}

#include <QtCore/QCoreApplication>
#include <QSqlDatabase>
#include <QtDebug>
#include <QFile>
#include <QStringList>

void init() {
	QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
	db.setDatabaseName("custom.db");
	Q_ASSERT_X(db.open(), "init()","Can't open db");
	qDebug() << "[init]\tSUCCES";
	qDebug() << "[init]\t" << db.tables();
}

void close() {
	QSqlDatabase db = QSqlDatabase::database();
	db.close();
	qDebug() << "[close]\tclose Invoked";
}

void remove_db() {
	if(QFile::remove("custom.db"))
		qDebug() << "[remove_db]\tSUCCES";
	else
		qDebug() << "[remove_db]\tFAILURE";
}

int main(int argc, char *argv[])
{
	 QCoreApplication a(argc, argv);
	 init();
	 remove_db();
	 close();
	 remove_db();
	 return a.exec();
}