MySql Deploy App....HELP!!

SGaist

Hi and welcome to devnet,

Do you also have the MySQL client libraries deployed with your application ?

hskoglund

Ok. You could try debugging, turn on a trace when Qt loads the plugins.
Before starting your app, set an environment variable to enable the trace:
SET QT_DEBUG_PLUGINS=1

To see the trace output, you can download the DebugView program

shathcock

@SGaist I copied the libmysql.dll file into the application directory to no avail and also tried copying it and the libmysel.lib files to the c:\windows directory.

SGaist

Don't put anything in the windows folder. Next step is what @hskoglund suggested

shathcock

ok the 3 Lines I see that seem to be the ones in the debug

QSalDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers;
QSqlDatabase: an instance of QCoreApplication is required for loading driver plugins

SGaist

The question is going to be silly but: Are you instantiating a QApplication (or Gui or Core) as the first thing in your main function ?

shathcock

Yeah I am just using the normal Windows Application Setup Which has QApplication a (argc, argv); as the first line then just creates an instance of mainwindow.

SGaist

Can you check what QCoreApplication::libraryPaths(); returns ?

shathcock

When I run it from creator it returns the release directory of the release folder that it creates and puts everything into. In other words the directory it puts the .exe file into sorry it's bee a long few days.

hskoglund

Hi, one more thing you could try (since your app runs fine when launched from Qt Creator):
define the environment variable (SET QT_DEBUG_PLUGINS=1) also in Qt Creator (in the Projects Tab, you can set it in Build Environment) then start your app and compare the trace output to the one you got with errors before.

shathcock

Any other Ideas this just really doesn't make any sense. It runs perfectly from the directory that it is compiled to but I can't move it anywhere else and have the MySql drivers working.

hskoglund

Here's another: try skipping using windeployqt; instead switch to using manual deployment, use this nice guide

shathcock

@hskoglund Ok tried it Same Thing!!

hskoglund

Hmmm... The deployment directory/the installation folder your app refuses to run from, is that inside C:\Program Files (x86) or a more normal folder like C:\Qt?

shathcock

No I have it on the Desktop I'll try though!!

shathcock

@shathcock Nope same thing!!!

hskoglund

Hmmmm, if I understand correctly: you have 2 directories/folders with identical contents but in different places on your C: drive. When you doubleciick to launch your app in one of them everything is fine and dandy, but when you try doubleclicking your app in the other directory you get that mysql plugin loading error?

shathcock

@hskoglund Basically yes. The one directory that is does run out of is the one that it is placed into when it is compiled, in other words the build..........\release folder. When I move the app.exe file and try to build a distribution folder it just all falls apart. The app actually runs but no database connection. I will say this also I spent 3 days with it not running until I set the environment variable QT_QPA_PLATFORM_PLUGIN_PATH. Could that be the problem. Sorry my brain is fried from trying to figure this stuff out.

hskoglund

Aha, I see :-)
The QT_QPA_PLATFORM_PLUGIN_PATH fiddling explains why in that debug trace above there are no database dlls listed, because Qt is barking up the wrong tree I mean directory. (Because while settingQT_QPA_PLATFORM_PLUGIN_PATH takes care of custom loading qwindows.dll from a directory of your choosing, it leaves other plugins like database guys stranded.)

QSalDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers; <-- no DLLs listed here
QSqlDatabase: an instance of QCoreApplication is required for loading driver plugins

So try placing the directory sqldrivers next to your .exe file, that should do it (just copy it from C:\5.5\msvc2013\plugins)

shathcock

Ok so I already ad a sqldrivers folder in the same directory with the .exe file but I re-copied it anyway and changed the QT_QPA_PLATFORM_PLUGIN_PATH to point to the directory in that folder since I actually had pointed it to the directory in the qt installation and same thing still runs no database. I think I am loosing my mind over this.....