Encoding issue with MySQL and Arabic - Qt 5.8 on Windows 7 - mysql

Question

I have an application where I use a QSqlQueryModel and a table view to view some data from a mysql database.
I created the database using phpMyadmin and wrote a Python script to read Arabic data from Excel sheets and insert it into the database.
Everything works well on Linux, but when I switched to Windows, the application can't seem to encode the Arabic words correctly.
This is how it looks like for the avilable data:
صودق بالعلاج ةالمتابعه بقسم(المخ والاعصاب)
...and when I insert new data using Qt, the data shows as question marks (?).
Here's the MySQL dump for the database:
-- MySQL dump 10.13 Distrib 5.6.21, for Win32 (x86)
--
-- Host: localhost Database: tasdeek
-- ------------------------------------------------------
-- Server version 5.6.21
/*!40101 SET #OLD_CHARACTER_SET_CLIENT=##CHARACTER_SET_CLIENT */;
/*!40101 SET #OLD_CHARACTER_SET_RESULTS=##CHARACTER_SET_RESULTS */;
/*!40101 SET #OLD_COLLATION_CONNECTION=##COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET #OLD_TIME_ZONE=##TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET #OLD_UNIQUE_CHECKS=##UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET #OLD_FOREIGN_KEY_CHECKS=##FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET #OLD_SQL_MODE=##SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET #OLD_SQL_NOTES=##SQL_NOTES, SQL_NOTES=0 */;
--
-- Table structure for table `tasdeek`
--
DROP TABLE IF EXISTS `tasdeek`;
/*!40101 SET #saved_cs_client = ##character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `tasdeek` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`rank` varchar(15) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`name` varchar(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`working` varchar(15) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`notes` text CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`amount` varchar(25) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`relationship` varchar(15) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`startDate` date NOT NULL,
`endDate` date NOT NULL,
`agency` tinyint(4) NOT NULL,
`nationalId` varchar(14) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=899 DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = #saved_cs_client */;
--
-- Dumping data for table `tasdeek`
--
LOCK TABLES `tasdeek` WRITE;
/*!40000 ALTER TABLE `tasdeek` DISABLE KEYS */;
INSERT INTO `tasdeek` VALUES (2,'مساعد','زياد شسيشسي شيسي','شسيش ','شيشسيشيسشي ي شسيشس ي شسي د','5000','شخصه','2017-02-06','2018-02-06',1,NULL),(3,'اتتلاتل تلات لات لا','سيشس شيشسي شسي ','','شيسيشسي ششي شسف شسيشي شسيشي // تجديد','5000','الوالد','2017-05-11','2018-05-11',1,NULL)
/*!40000 ALTER TABLE `tasdeek` ENABLE KEYS */;
UNLOCK TABLES;
--
-- Table structure for table `users`
--
DROP TABLE IF EXISTS `users`;
/*!40101 SET #saved_cs_client = ##character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`password` varchar(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`userGroup` int(2) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `UNIQUE` (`username`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
/*!40101 SET character_set_client = #saved_cs_client */;
--
-- Dumping data for table `users`
--
LOCK TABLES `users` WRITE;
/*!40000 ALTER TABLE `users` DISABLE KEYS */;
INSERT INTO `users` VALUES (1,'admin','5bdba65d1a953aa83ed8f35ef2877274b5d451d2',0);
/*!40000 ALTER TABLE `users` ENABLE KEYS */;
UNLOCK TABLES;
/*!40103 SET TIME_ZONE=#OLD_TIME_ZONE */;
/*!40101 SET SQL_MODE=#OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=#OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=#OLD_UNIQUE_CHECKS */;
/*!40101 SET CHARACTER_SET_CLIENT=#OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=#OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=#OLD_COLLATION_CONNECTION */;
/*!40111 SET SQL_NOTES=#OLD_SQL_NOTES */;
-- Dump completed on 2017-09-13 21:40:59
Note that the old data inserted on Linux is shown properly on phpMyAdmin.

Answer 1

See this fragment from QTextCodec::codecForLocale documentation:
On Windows, the codec will be based on a system locale. On Unix systems, the codec will might fall back to using the iconv library if no builtin codec for the locale can be found.
This could explain why you saw the correct arabic characters on Linux, but not on Windows.
As an alternative in this case, you can "force" the codec using the following instruction in your main.cpp:
QTextCodec::setCodecForLocale( QTextCodec::codecForName("UTF-8") );
PS: Don't forget the #include <QTextCodec> directive.