QSqlTableModel::insertRecord() fails with QSqlDatabase with a non-default connection name

Using Qt 4.8.6 and clang++ x86_64-apple-darwin14.3.0 on my late-2014 MacBook Pro I find that QsqlTableModel::insertRecord() fails to write the target MYSQL database: myDB while constructing the QSqlDatbase: myDB using a non-default connection such as:

db = QSqlDatabase::addDatabase("QMYSQL","Connection1");

and insertRecord(-1,myRecord) evaluates to false.

Instead, if I use the usual default connection:

db = QSqlDatabase::addDatabase("QMYSQL");

the database is appended successfully as:

mysql> select * from myTable;
+------+------+
| col1 | col2 |
+------+------+
|    1 |    2 |
|    5 |    6 |
+------+------+
2 rows in set (0.00 sec)

The usual recommendation to accommodate multiple connection names is to construct QSqlQuery with QSqlDatabase as:

QSqlQuery query(db)

that evidently doesn't seem to help in this case. Can you point out what's missing?

The small amount of runnable code that exemplifies the above is below:

testdb.h

#ifndef TESTDB_H
#define TESTDB_H

#include <QtSql>
#include <QtCore>


class TestDB
{
public:
    TestDB();
    ~TestDB();
    void dbInit();
    void appendDB(const int &col1, const int &col2);
private:
    QSqlDatabase db;
    QSqlTableModel *model;
};

#endif // TESTDB_H

testdb.cpp

#include "testdb.h"

TestDB::TestDB()
{
    dbInit();
}

TestDB::~TestDB()
{

}

void TestDB::dbInit()
{
    // database connection
    db = QSqlDatabase::addDatabase("QMYSQL","Connection1");
    db.setDatabaseName("myDB"); 
    db.setUserName("root");
    db.setPassword("");
    db.setHostName("localhost");
    db.setConnectOptions();
    if (!db.open())
    {
        qDebug() << "Database error occurred in class: stockinfo" << db.lastError().text();
    }
    QSqlQuery query(db);

    // create database named transactions
    query.exec("CREATE DATABASE IF NOT EXISTS myDB;");
    query.exec("USE myDB;");
    query.exec("CREATE TABLE IF NOT EXISTS myTable("
                   "col1 INT,"
                   "col2 INT"
                   ");");
    model = new QSqlTableModel;
    model->setTable("myTable");
    model->select();
}

void TestDB::appendDB(const int &col1, const int &col2)
{
    QSqlRecord myRecord;
    myRecord.append(QSqlField("col1", QVariant::Int));
    myRecord.append(QSqlField("col2", QVariant::Int));

    myRecord.setValue("col1",col1);
    myRecord.setValue("col2",col2);

    model->insertRecord(-1,myRecord);
    qDebug() << "model->insertRecord(-1,myRecord) = " << model->insertRecord(-1,myRecord);
    qDebug() << "Last Database error: " << db.lastError().text();
}

main.cpp

#include <QCoreApplication>
#include <testdb.h>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    TestDB myTestDB;
    myTestDB.appendDB(1,2);
    myTestDB.appendDB(5,6);
    return a.exec();
}

dbTest.pro

QT       += core sql

QT       -= gui

TARGET = dbTest
CONFIG   += console
CONFIG   -= app_bundle

TEMPLATE = app


SOURCES += main.cpp \
    testdb.cpp

HEADERS += \
    testdb.h