Building database driver, IT difficulties

[SPlatten]

@KroMignon , just checked the source for vcvarsall.bat, if no command line arguments are passed then it defaults to x86.

This is my build batch file:

echo Cleaning cache
@rm -R config.*
echo Calling vcvarsall.bat
@call "c:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/vcvarsall.bat"
echo Running qmake
echo Release...
@c:/Qt/Qt5.9.2/5.9.2/msvc2015/bin/qmake -- MYSQL_INCDIR="/c/Program Files (x86)/MariaDB 10.5/include/mysql" MYSQL_LIBDIR="/c/Program Files (x86)/MariaDB 10.5/lib" MYSQL_LIBS="-lmariadb"
echo Debug...
@c:/Qt/Qt5.9.2/5.9.2/msvc2015/bin/qmake "CONFIG+=debug" -- MYSQL_INCDIR="/c/Program Files (x86)/MariaDB 10.5/include/mysql" MYSQL_LIBDIR="/c/Program Files (x86)/MariaDB 10.5/lib" MYSQL_LIBS="-lmariadb"
echo Running nmake
@nmake
echo Running nmake install
@nmake install

[KroMignon]

@SPlatten AFAIK, to build MySQL plugin you need MySQL Connector/C 6.1.5 or less (https://downloads.mysql.com/archives/c-c/).
If you are using a newer version MySQL Connector/C, SQL-Transaction will not work, for example (it takes me days to find that out).

I am not sure it works with MariaDB Connector.

[SPlatten]

@KroMignon , I'm not sure:

@c:/Qt/Qt5.9.2/5.9.2/msvc2015/bin/qmake -- MYSQL_INCDIR="/c/Program Files (x86)/MariaDB 10.5/include/mysql" MYSQL_LIBDIR="/c/Program Files (x86)/MariaDB 10.5/lib" MYSQL_LIBS="-lmariadb"

Is correct ? Qt doesn't support mariadb, its not listed in the list of configurations, so shouldn't the lib name at the end be:

@c:/Qt/Qt5.9.2/5.9.2/msvc2015/bin/qmake -- MYSQL_INCDIR="/c/Program Files (x86)/MariaDB 10.5/include/mysql" MYSQL_LIBDIR="/c/Program Files (x86)/MariaDB 10.5/lib" MYSQL_LIBS="-lmysql"

Also, no where in the above does the actual location of the connector c download feature, its referencing the installation of MariaDB itself not the connector.

[KroMignon]

@SPlatten said in Building database driver, IT difficulties:

I'm not sure:

I don't understand why you ask for help and don't try out what people told you to do.
I have used "MySQL Connector/C 6.1.5" and it works fine.
You try to use MariaDB Connector and qmake do NOT enable MySQL plugin.

So up to you to continue on this way or to do what I told you to do.

[SPlatten]

@KroMignon , Does the MySQL Connector work with Maria DB ? I will try downloading the mysql connector.

[SPlatten]

@KroMignon , I downloaded and installed the MySQL connector, selecting version 6.1.5, same problem, it does not connect.

Initialising application core...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2d.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2d.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "direct2d"
        ]
    },
    "className": "QWindowsDirect2DIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2d.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2dd.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2dd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "direct2d"
        ]
    },
    "className": "QWindowsDirect2DIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("direct2d")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimal.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimal.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimal.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimald.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimald.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreen.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreen.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreen.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreend.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreend.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindows.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindows.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "windows"
        ]
    },
    "className": "QWindowsIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindows.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindowsd.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindowsd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "windows"
        ]
    },
    "className": "QWindowsIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("windows")
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/platforms" ...
loaded library "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindowsd.dll"
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/styles" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/styles" ...
Connecting to database...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlite.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlite.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "className": "QSQLiteDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlite.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlited.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlited.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "className": "QSQLiteDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysql.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysqld.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbc.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbc.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "className": "QODBCDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbc.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbcd.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbcd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "className": "QODBCDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QODBC3", "QODBC")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsql.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsqld.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/sqldrivers" ...
Cannot load library C:\Qt\Qt5.9.2\5.9.2\msvc2015\plugins\sqldrivers\qsqlmysqld.dll: The specified module could not be found.
QLibraryPrivate::loadPlugin failed on "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysqld.dll" : "Cannot load library C:\\Qt\\Qt5.9.2\\5.9.2\\msvc2015\\plugins\\sqldrivers\\qsqlmysqld.dll: The specified module could not be found."
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7

I just checked the path:

C:\Qt\Qt5.9.2\5.9.2\msvc2015\plugins\sqldrivers

Whilst this folder does contain 12 files, 8 of these files in this folder have an up to date timestamp, except:

qsqlmysql.dll
qsqlmysqld.dll
qsqlpsql.dll
qsqlpsqld.dll

Which all have a date timestamp of:

02/10/2017 07:06

[KroMignon]

@SPlatten said in Building database driver, IT difficulties:

QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/sqldrivers" ...

Cannot load library C:\Qt\Qt5.9.2\5.9.2\msvc2015\plugins\sqldrivers\qsqlmysqld.dll: The specified module could not be found.

I downloaded and installed the MySQL connector, selecting version 6.1.5, same problem, it does not connect.

Do did you do exactly?

• Did you re-run qmake with right parameters?
• Did you check if MySQL plugin is now enabled?
• did you run "nmake clean & nmake build & nmake installl" ?

You seems to like batch file, it should look like this:

echo Cleaning cache
@rm -R config.*
echo Calling vcvarsall.bat
@call "c:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/vcvarsall.bat"
echo Configure Qt
@call "c:/Qt/Qt5.9.2/5.9.2/msvc2015/bin/qtenv2.bat"
echo Running qmake
@qmake -- MYSQL_INCDIR="c:/mysql-connector-6.1.5/include" MYSQL_LIBDIR="c:/mysql-connector-6.1.5/lib"
@rem I add a pause here to be able to check if MySQL plugin is enabled
@pause 
echo Clean old build
@nmake clean
echo Running nmake
@nmake
echo Running nmake install
@nmake install

EDIT: add nmake clean to ensure (re)build will be done

[jsulm]

@SPlatten said in Building database driver, IT difficulties:

"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysql.dll' uses incompatible Qt library. (Cannot mix debug and release

Did you notice this?

[SPlatten]

@KroMignon , I downloaded the MSI install for the mysql connector 6.1.5 and used it to install, I don't see the path:

c:\mysql-connector-6.1.5

I found it in:

C:\Program Files (x86)\MySQL\MySQL Connector C 6.1

Modify batch file with correct paths and run. qsqlmysql.dll and qsqlmysqld.dll now have up to date timestamps. Rebuilt project and run in Qt Creator:

Initialising application core...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2d.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2d.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "direct2d"
        ]
    },
    "className": "QWindowsDirect2DIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2d.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2dd.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qdirect2dd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "direct2d"
       ]
    },
    "className": "QWindowsDirect2DIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("direct2d")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimal.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimal.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimal.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimald.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qminimald.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreen.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreen.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreen.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreend.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qoffscreend.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindows.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindows.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "windows"
        ]
    },
    "className": "QWindowsIntegrationPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindows.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindowsd.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindowsd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "windows"
        ]
    },
    "className": "QWindowsIntegrationPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("windows")
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/platforms" ...
loaded library "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platforms/qwindowsd.dll"
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/styles" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/styles" ...
Connecting to database...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlite.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlite.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "className": "QSQLiteDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlite.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlited.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlited.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "className": "QSQLiteDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysql.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysqld.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbc.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbc.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "className": "QODBCDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbc.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbcd.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlodbcd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "className": "QODBCDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QODBC3", "QODBC")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsql.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 329986
}
 
 
"The plugin 'C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsqld.dll"
Found metadata in lib C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlpsqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": true,
    "version": 329986
}
 
 
Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/simon.platten/Documents/vechicle-training-server-application/build-training-server-application-Desktop_Qt_5_9_2_MSVC2015_32bit-Debug/debug/sqldrivers" ...
Cannot load library C:\Qt\Qt5.9.2\5.9.2\msvc2015\plugins\sqldrivers\qsqlmysqld.dll: The specified module could not be found.
QLibraryPrivate::loadPlugin failed on "C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers/qsqlmysqld.dll" : "Cannot load library C:\\Qt\\Qt5.9.2\\5.9.2\\msvc2015\\plugins\\sqldrivers\\qsqlmysqld.dll: The specified module could not be found."
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7

Still no joy. As mentioned above the path:

C:/Qt/Qt5.9.2/5.9.2/msvc2015/plugins/sqldrivers

Now contains build dll's for both qsqlmysql.dll and qsqlmysqld.dll with up to date timestamps.

[KroMignon]

@SPlatten said in Building database driver, IT difficulties:

Modify batch file with correct paths and run. qsqlmysql.dll and qsqlmysqld.dll now have up to date timestamps. Rebuilt project and run in Qt Creator:

You partially reply to my question:

• did you check if MySQL plugin build is enabled after qmake?
• according to debug output, the plugin is not available in debug mode. So qsqlmysqld.dll seems not to by copied to to right place. Are you sure nmake install has been done without errors?

[EDIT]
Are you sure that libmysql.dll is in the PATH?
I would recommend you to copy this dll from C:\Program Files (x86)\MySQL\MySQL Connector C 6.1\lib to C:\Qt\Qt5.9.2\5.9.2\msvc2015\bin

[SPlatten]

@KroMignon , output from running:

$ c:/Qt/Qt5.9.2/5.9.2/msvc2015/bin/qmake
 
Running configuration tests...
Done running configuration tests.
 
Configure summary:
 
Qt Sql:
  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, Qt is installed.
You should NOT run 'nmake install'.
Note that this build cannot be deployed to other machines or devices.
 
Prior to reconfiguration, make sure you remove any leftovers from
the previous build.

[KroMignon]

@SPlatten

Are you sure that libmysql.dll is in the PATH?
I would recommend you to copy this dll from C:\Program Files (x86)\MySQL\MySQL Connector C 6.1\lib to C:\Qt\Qt5.9.2\5.9.2\msvc2015\bin

[SPlatten]

@KroMignon , Excellent, that last bit copying the dll from:

C:\Program Files (x86)\MySQL\MySQL Connector C 6.1\lib

to:

C:\Qt\Qt5.9.2\5.9.2\msvc2015\bin

Has fixed the issue. Thank you for your time and efforts.