MYSQL / QT issues

Jdonoher

Hi Im having issues connecting up QT with MYSQL, I managed to get MYSQL as an available driver, however when trying to connect to a db I get the following:
" QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMARIADB QMYSQL QODBC QPSQL"

From what I understand Ive not connected qt with mysql, I have a mysql connector as well just need to link them.. I think. I try following the steps in here, but I just dont understand how to run qmake through the cmd line.I match the directory but 'qmake' is not recognized appears as expected, I see no way of opening a qt specific cmd line, I do not gwt the QT for desktop I have seen suggested on other threads and am a bit lost.

SGaist

Hi and welcome to devnet,

Did you already try to run your application with the QT_DEBUG_PLUGINS environment variable set to 1 ?

Because from the looks of it, you have the drivers themselves ready to use.

Jdonoher

Hi thanks for the response, sorry im a complete qt novice I've seen reference to QT_DEBUG_PLUGINS but I have no idea where this is or how to change it? * edit : I think I have set it: however on running I still get just the same error.

SGaist

The environment variable won't fix your error, it will dump a lot of information about what is going on with your plugins.

As for editing it, do it in the Run part of the Project panel.

Jdonoher

ahhhh got you the follwing was spat out regarding Mysql:
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/6.2.3/mingw_64/plugins/sqldrivers/qsqlmysql.dll"
Found metadata in lib C:/Qt/6.2.3/mingw_64/plugins/sqldrivers/qsqlmysql.dll, metadata=
"QMYSQL",
"className": "QMYSQLDriverPlugin",
Got keys from plugin meta data QList("QMYSQL", "QMARIADB")
Cannot load library C:\Qt\6.2.3\mingw_64\plugins\sqldrivers\qsqlmysql.dll: The specified module could not be found.
QLibraryPrivate::loadPlugin failed on "C:/Qt/6.2.3/mingw_64/plugins/sqldrivers/qsqlmysql.dll" : "Cannot load library C:\Qt\6.2.3\mingw_64\plugins\sqldrivers\qsqlmysql.dll: The specified module could not be found."
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMARIADB QMYSQL QODBC QPSQL

SGaist

Can the connector .dll be found ?

Jdonoher

Hi sorry not sure where to see this, there was no mention of connector .dll in the debuf_plugin message, I think I need to follow this step: compiling driver. However I dont have a qt command prompt and am struddling to run through the standard windows cmd line. Aslo in looking at other threads, I do not have a .pro in the mysql folder in ~src/plugins/sqldrivers/mysql could this be the issue?

SGaist

Based on the output, you already have the .dll.

As for the MySQL connector .dll, where did you install MySQL ?

Jdonoher

I downloaded the C connector from here
And donwloaded it to C:\Program Files

SGaist

Then, do you have that path in your PATH environment variable ? (Still in Qt Creator)

Jdonoher

There isnt one so Im guessing I add PATH as the variable and the value being the dir?

SGaist

PATH is already defined, you may have to check a checkbox on the Run panel in order to have access to it.

Jdonoher

Hi, I couldnt find the PATH variable but ran this command in main.cpp:
QCoreApplication::addLibraryPath("C:\Program Files\MySQL");
However this didnt change any of the logs. Im a bit lost with where to go from here

Jdonoher

@SGaist I have also tried to compile driver using the following in the command prompt :
C:\Qt\6.2.3\Src\qtbase\src\plugins\sqldrivers>qmake -version
QMake version 3.1
Using Qt version 6.2.3 in C:/Qt/6.2.3/mingw_64/lib

C:\Qt\6.2.3\Src\qtbase\src\plugins\sqldrivers>qmake -- MYSQL_INCDIR="C:/Program Files/MySQL/MySQL Connector C 6.1/include" MYSQL_LIBDIR="C:/Program Files/MySQL/MySQL Connector C 6.1/lib"

However it doesnt do anything after the second command, just gives me basic qmkae info.

JonB

@Jdonoher said in MYSQL / QT issues:

QCoreApplication::addLibraryPath("C:\Program Files\MySQL");

Did you really copy and paste this line from your C++ source code file? Please copy and paste whatever you have literally, do not type it in by hand.....

Jdonoher

@JonB It was copied.

I tired with'\' and '/' just in case but either way didnt help.

Jdonoher

I've alslo managed to finally get .pro file in my /mysql dir in src. However it cannot build, I have included the include path from the mysql connector as well as added the lib to LIBS. but am getting 3 errors:

Here is mysql.pro file:

JonB

@Jdonoher
I could be wrong, but because your paths have spaces in them I would have expected them to need to be quoted, like:

INCLUDEPATH += "C:/Program Files/MySQl/MySQL Connector C 6.1/include"
LIBS += "C:/Program Files/MySQl/MySQL Connector C 6.1/lib"

Jdonoher

@JonB yeah Ive tried both ways multiple times and still errors, strangely I get more build errors with quotes than without but quotes certainly feel necessary

Christian Ehrlicher

Simply move it to a folder without spaces...