QMYSQL driver not loaded and Library mysql is not defined

Markyo

@jsulm I'm building in this folder:

C:\Qt\5.12.5\Src\qtbase\src\plugins\sqldrivers

I'm not sure I have to delete this folder

jsulm

@Markyo Well, since you're not doing out of source build you should not delete it. Instead delete all build artefacts (files created during your build attempts) manually.

Markyo

@jsulm are there files other than config.cache?

Mickleholts

This post is deleted!

SGaist

@Mickleholts hi,

@jsulm already fave quite a lot of advices. Did you follow them ?

Markyo

Hello, I'm coming back here again to look for some solutions !
Due to difference of version, I reinstalled another version, several times, and for my last try, with this command:

C:\Qt\5.12.5\msvc2017\bin\qmake.exe -- MYSQL_INCDIR="C:\Program Files\MySQL\MySQL Connector C 6.1\include" MYSQL_LIBDIR="C:\Program Files\MySQL\MySQL Connector C 6.1\lib"

I get this environment problem:

Project ERROR: Cannot run compiler 'cl'. Output:
===================
===================
Maybe you forgot to setup the environment?

Honestly, I don't understand why it is so hard to use the MySQL driver..

Christian Ehrlicher

@Markyo said in QMYSQL driver not loaded and Library mysql is not defined:

Maybe you forgot to setup the environment?

You did not set up the MSVC environment as the error tells you - you have to run it from a MSVC command prompt. Nothing Qt specific - if you want to use a compiler in an environment you have to properly set it up.

Honestly, I don't understand why it is so hard to use the MySQL driver..

Ask Oracle why they changed their license so it can be shipped as pre-build library

jsulm

This post is deleted!

Markyo

@Christian-Ehrlicher thx so much it worked, the command tell me this:

Running configuration tests...
Checking for DB2 (IBM)... no
Checking for InterBase... no
Checking for MySQL... yes
Checking for OCI (Oracle)... no
Checking for ODBC... yes
Checking for PostgreSQL... no
Checking for SQLite (version 2)... no
Checking for TDS (Sybase)... no
Done running configuration tests.

Configure summary:

Qt Sql Drivers:
  DB2 (IBM) .............................. no
  InterBase .............................. no
  MySql .................................. yes
  OCI (Oracle) ........................... no
  ODBC ................................... yes
  PostgreSQL ............................. no
  SQLite2 ................................ no
  SQLite ................................. yes
    Using system provided SQLite ......... no
  TDS (Sybase) ........................... no

Qt is now configured for building. Just run 'nmake'.
Once everything is built, you must run 'nmake install'.
Qt will be installed into 'C:\Qt\5.12.5\msvc2017'.

Prior to reconfiguration, make sure you remove any leftovers from
the previous build.

So, MySQL is available, I typed nmake, then nmake install, then nmake install in mysql directory, everything seems to work.

I rebuilt my app, and ran the app and get this:

QML debugging is enabled. Only use this in a safe environment.
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7

Don't understand why it is available but not loaded.

SGaist

The driver needs the dlls to be loaded.

You can help finding them modifying the PATH environment variable in the Run part of the Project panel in Qt Creator.

Markyo

@SGaist After editing PATH variable to add dll's path, it finally worked !

Thank you so much everyone for your time and helpful responses !

Markyo

@SGaist Hello! I'm building a second app using QMySQL database, the first app (the one about this topic) works perfectly as expected, but the second tells me that the driver isn't loaded.

QSqlDatabase: MYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7

I added mysql dll dir in PATH environment variable, but same problem stay the same..

Have you an idea please?

EDIT: nevermind, I'm just stupid, I forgot the "Q" before "MYSQL" call in code line:

QSqlDatabase db = QSqlDatabase::addDatabase("MYSQL");

Now it's:

QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");

and strangely, works better..

Again, thank you all for your help!