If you face this problem in general Qt MySQL or MariaDB then follow this topic Qt MySQL (MariaDB) Driver Not Loaded , The Solution below is customized for Sohag Builder.
Sohag Builder by default includes the required drivers to connect to all the suppored database servers (PostgreSQL, MariaDB, MySQL and SQLite), But you may need additional libraries to be able to connect to database if you are using MySQL or MariaDB database servers .
1- Connecting to MariaDB on MS Windows.
A- Sohag Builder connects to MariaDB using libmysql.dll library, You can find this library at the directory lib in the root directory of your MariaDB installation.
Mariadb installation dir / lib
You may found libmariadb.dll instead of libmysql.dll, If this is the case simply copy libmariadb.dll and rename the copy to libmysql.dll (do not rename the original libmariadb.dll this may prevent you from connecting to MariaDB using another application).
B- If you have proceed A and still not able to connect, you can do one of the following two steps.
B.1- Copy libmysql.dll to Sohag Builder root directory.
This way is simpler but the second is preferable.
B.2- Add the MariaDB lib path to the path enviroment variable.
If you can’t find or libmariadb.dll or you don’t have MariaDB installed on your computer then you need to install MariaDB C++ connector to your computer the try the previous steps.