QSqlDatabase Driver not loaded

hskoglund

Hi is there any difference if you put libmysqld.dll in the same directory as your .exe file?

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I already have it in the same directory. However, I don't know it if works. It seems that it isn't detected by the program:

QFactoryLoader::QFactoryLoader() looking at "C:/Qt/5.11.1/msvc2017_64/plugins/sqldrivers/libmysqld.dll"
"Failed to extract plugin meta data from 'C:/Qt/5.11.1/msvc2017_64/plugins/sqldrivers/libmysqld.dll'"
         not a plugin

SGaist

As @hskoglund wrote: in the same folder as your application executable, not in the folder of the plugin.

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It is in the .exe and also plugin folder. I deleted the one from plugin directory and now log looks like this: pastebin - the libmysqld.dll file is not even loaded. This is the plugin folder: imgur and the .exe directory: imgur

hskoglund

Hmm that error 0x000000c1 could mean your 64-bit MySql is not installed 100%.

If you compile in Release mode instead of Debug, you get that same error 0x000000c1?

Edit: also check that you indeed installed the 64-bit version of MySql and not the 32-bit version, easiest way to check:
mysql.exe --V

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I had 64-bit MySql Server and 32-bit C Connector so I replaced it with 64-bit C++ Conector. I have tried compiling in the Release mode with no success. Should I reinstall the Qt libraries?

Cannot load library C:\Qt\5.11.1\msvc2017_64\plugins\sqldrivers\qsqlmysql.dll

I think this may be the problem - file is in the directory but is not recognized by the program.

hskoglund

I think the qsqlmysql.dll file is ok, but since it's depending on libmysql.dll being present in the same directory as your Qt .exe file, if that libmysql.dll is 32-bit, then you could have an error anyway.

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Can I download it (64 bit, Qt 5.11.1) without reinstalling the whole Qt?

hskoglund

I think you can do it by downloading the offline installer (never tried it) but easiest is most likely just to start MaintenanceTool.exe, remove the 5.11.1 MSVC2017 64-bit component and then selecting/installing it again.

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I have reinstalled the Qt libraries and replaced all the files in the exe directory with the newer version, and it works now. This is what I have in the folder: exe file, libmysql.dll, Qt5Core.dll and Qt5Sql.dll (in release mode).

Thank you for help!