error while connection to Database

JonB

@raven-worx said in error while connection to Database:

@Allerknappe said in error while connection to Database:

i get this error in the first line of the code

i would say the crash is not related to the lines of code you've posted.
How do you know it's that line of code? Did you run it in the debugger?

A missing mysql lib won't cause a seg fault. It would just prevent the plugin from being loaded successfully, but it wouldn't cause a crash.

The OP stated "i get this error in the first line of the code", so I took him at his word! :) Anyway a back trace in gdb should confirm.

A missing mysqllib etc. may not crash, but the wrong/inconsistent versions of the necessary libmysqlqt or whatever it's called and other libraries under Linux can do, in my experience... :)

Allerknappe

ok thanks for the fast answers,

i see now that i have skipped the section with the QMYSQL driver so that i never have installed some driver :( ...
now i tried the description from here sql-driver but how so often i think i do something wrong.
i loaded the mysql installer for the needed .lib and then i try to run:

cd $QTDIR/qtbase/src/plugins/sqldrivers/mysql
qmake "INCLUDEPATH+=C:/mysql/MySQL/MySQLConnector.C6.1/include" "LIBS+=C:/mysql/MySQL/MySQLServer5.7/lib/libmysql.lib" mysql.pro
make

After this i try to set my configure for the mysql database :
c:\qt\5.9.1\Src>configure -sql-mysql

but i still get the error: ERROR: Feature 'sql-mysql' was enabled, but the pre-condition 'libs.mysql' failed.

you have some experience with my problem?

thanks a lot

Allerknappe

so i tried this:
*
****Works for me on Windows with Qt SDK 5.6.0 (32bit version with mingw 4.9.2 32bit included) :

Downloaded MySQL 32bit in zip archive (mine was v5.7.11)
Extracted it to C:/MySQL
Copied "C:\Qt\QMySQL\lib\libmysql.dll" and "C:\Qt\QMySQL\lib\libmysqld.dll" to Windows/System32 (to avoid the "cannot found -llibmysql" compilation error)
Compile with "How to Build the QMYSQL Plugin on Windows" on http://doc.qt.io/qt-5/sql-driver.html#qmysql (my command was "qmake "INCLUDEPATH+=C:\Qt\QMySQL\include" "LIBS+=C:\Qt\QMySQL\lib\libmysql.lib" sql.pro" and "mingw32-make")
After compilation succeeded, copy (the freshly compiled) Qt5Sql.dll & Qt5Sqld.dll from "C:\Qt\Qt5.6.0\5.6\Src\qtbase\lib" to your application build directory
Restart QtCreator, that should work*****

but when i run the cmd with this statements i get this outline:

**C:\qt\5.9.1\mingw53_32>cd C:\qt\5.9.1\Src\qtbase\src\plugins\sqldrivers\mysql

C:\qt\5.9.1\Src\qtbase\src\plugins\sqldrivers\mysql>qmake "INCLUDEPATH+=C:\mysql\MySQL\MySQLConnector.C6.1\include" "LIBS+=C:\mysql\MySQL\MySQLConnector.C6.1\lib\libmysql.lib" mysql.pro

C:\qt\5.9.1\Src\qtbase\src\plugins\sqldrivers\mysql>make
make -f Makefile.Release all
make[1]: Entering directory 'C:/qt/5.9.1/Src/qtbase/src/plugins/sqldrivers/mysql'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory 'C:/qt/5.9.1/Src/qtbase/src/plugins/sqldrivers/mysql'
make -f Makefile.Debug all
make[1]: Entering directory 'C:/qt/5.9.1/Src/qtbase/src/plugins/sqldrivers/mysql'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory 'C:/qt/5.9.1/Src/qtbase/src/plugins/sqldrivers/mysql'**

the C:\qt\5.9.1\Src\qtbase\lib directory is also empty so that only the README said, that i´m probably forget to compile the qt library, and yes i never compile something i only install qt and compile in the creator my code.

some help?

Allerknappe

ok now i run all the process from this http://doc.qt.io/qt-5/windows-building.html website.
Everything seems ok, but still i get the error:
ERROR: Feature 'sql-mysql' was enabled, but the pre-condition 'libs.mysql' failed.
maybe some help`?

Allerknappe

So i tried new things:
i do all the things in the win cmd. it propably worked all well, till the end:
configure -debug -nomake examples -opensource #done
make #done
make install #done
cd C:\mysql\MySQL\MySQLConnector.C6.1\lib #done
reimp -d libmysql.lib #done
dlltool -k -d libmysql.def -l libmysql.a #done
cd C:\qt\5.9.1\Src #done
configure -I C:\mysql\MySQL\MySQLConnector.C6.1\include -L C:\mysql\MySQL\MySQLConnector.C6.1\lib #done
make sub-src #done
make install #done
cd C:\qt\5.9.1\Src\qtbase\src\plugins\sqldrivers\mysql
qmake "INCLUDEPATH+=C:\mysql\MySQL\MySQLConnector.C6.1\include" "LIBS+=-L. mysql" mysql.pro
make

the make statement gives me the following error:

ql_mysql_p.o -LC:\utils\my_sql\my_sql\lib -LC:\utils\postgresql\pgsql\lib -L. mysql -LC:\qt\5.9.1\Src\qtbase\lib C:\qt\5.9.1\Src\qtbase\lib\libQt5Sql.a C:\qt\5.9.1\Src\qtbase\lib\libQt5Core.a .obj\release\qsqlmysql_resource_res.o
g++: error: mysql: No such file or directory
Makefile.Release:67: recipe for target 'C:\qt\5.9.1\Src\qtbase\plugins\sqldrivers\qsqlmysql.dll' failed
make[1]: *** [C:\qt\5.9.1\Src\qtbase\plugins\sqldrivers\qsqlmysql.dll] Error 1
make[1]: Leaving directory 'C:/qt/5.9.1/Src/qtbase/src/plugins/sqldrivers/mysql'
Makefile:40: recipe for target 'release-all' failed

i have also find in the qt4.9 description additional these steps after my end:

Now the following libraries are ready in C:\Qt\4.6.2\plugins\sqldrivers.

libqsqlmysql4.a
libqsqlmysqld4.a
qsqlmysql4.dll
qsqlmysqld4.dll

ok i dont have the 4 at the end of the filename but i find the qsqlmysqld but not the qsqlmysql.dll , it seems that this file will not creat. But why?

Allerknappe

so i try to install qt 5.9.2 new .
have someone a step-by-step installation guide from a new installation to a working mysql plugin ?

JonB

@Allerknappe

Now the following libraries are ready in C:\Qt\4.6.2\plugins\sqldrivers.

Sorry, you seem to be saying either you have Qt4 SQL drivers for your Qt5 build, or you have Qt5 drivers but you've placed them in a directory named for Qt4 which I would guess is not looked at by Qt5??

Allerknappe

yes in my frustration i tried the installation guide How to Build the QMYSQL Plugin on Windows from the qt 4.9 part. i now that i use 5.9.1 but the 5.9 installation guide seems not to be working... so i tried the other guide and only change the 4.9 path to 5.9

JonB

@Allerknappe said in error while connection to Database:

and only change the 4.9 path to 5.9

Earlier you wrote:

Now the following libraries are ready in C:\Qt\4.6.2\plugins\sqldrivers

I leave you to verify your paths and that they are being searched correctly for 5.9.

Allerknappe

yeah sorry for the mistake i copied from a other side where the path was for 4.9 , for me i changed the path to 5.9

Allerknappe

ok, how i solve this problem :

C:\qt\5.9.2\Src\qtlocation\src\3rdparty\mapbox-gl-native/src/mbgl/gl/value.cpp:185: undefined reference to glBlendEquation@4' C:\qt\5.9.2\Src\qtlocation\lib\libqmapboxgld.a(value.o): In function ZN4mbgl2gl5value10BlendColor3SetERKNS_5ColorE':
C:\qt\5.9.2\Src\qtlocation\src\3rdparty\mapbox-gl-native/src/mbgl/gl/value.cpp:212: undefined reference to glBlendColor@16' C:\qt\5.9.2\Src\qtlocation\lib\libqmapboxgld.a(value.o): In function ZN4mbgl2gl5value7Program3SetERKj':
C:\qt\5.9.2\Src\qtlocation\src\3rdparty\mapbox-gl-native/src/mbgl/gl/value.cpp:224: undefined reference to glUseProgram@4' C:\qt\5.9.2\Src\qtlocation\lib\libqmapboxgld.a(value.o): In function ZN4mbgl2gl5value13ActiveTexture3SetERKh':
C:\qt\5.9.2\Src\qtlocation\src\3rdparty\mapbox-gl-native/src/mbgl/gl/value.cpp:248: undefined reference to glActiveTexture@4' C:\qt\5.9.2\Src\qtlocation\lib\libqmapboxgld.a(value.o): In function ZN4mbgl2gl5value15BindFramebuffer3SetERKj':
C:\qt\5.9.2\Src\qtlocation\src\3rdparty\mapbox-gl-native/src/mbgl/gl/value.cpp:285: undefined reference to `glBindFramebuffer@8'

Allerknappe

so if i try qmake "INCLUDEPATH+=C:/mysql/MySQL/MySQLConnector.C6.1/include" "LIBS+=C:/mysql/MySQL/MySQLConnector.C6.1/lib/libmysql.lib" mysql.pro
i only get the error Project ERROR: Library 'mysql' is not defined.
in the stash file is insert:

QMAKE_CXX.INCDIRS =
C:/qt/Tools/mingw530_32/lib/gcc/i686-w64-mingw32/5.3.0/include
C:/qt/Tools/mingw530_32/lib/gcc/i686-w64-mingw32/5.3.0/include-fixed
C:/qt/Tools/mingw530_32/i686-w64-mingw32/include
C:/qt/Tools/mingw530_32/i686-w64-mingw32/include/c++
C:/qt/Tools/mingw530_32/i686-w64-mingw32/include/c++/i686-w64-mingw32
C:/qt/Tools/mingw530_32/i686-w64-mingw32/include/c++/backward
QMAKE_CXX.LIBDIRS =
C:/qt/Tools/mingw530_32/lib/gcc/i686-w64-mingw32/5.3.0
C:/qt/Tools/mingw530_32/lib/gcc
C:/qt/Tools/mingw530_32/i686-w64-mingw32/lib
C:/qt/Tools/mingw530_32/lib
QMAKE_CXX.QT_COMPILER_STDCXX = 199711L
QMAKE_CXX.QMAKE_GCC_MAJOR_VERSION = 5
QMAKE_CXX.QMAKE_GCC_MINOR_VERSION = 3
QMAKE_CXX.QMAKE_GCC_PATCH_VERSION = 0
QMAKE_CXX.COMPILER_MACROS =
QT_COMPILER_STDCXX
QMAKE_GCC_MAJOR_VERSION
QMAKE_GCC_MINOR_VERSION
QMAKE_GCC_PATCH_VERSION

sometimes this hole errors are a little mysterious for me...

Allerknappe

ok i have a solution for my problem:

in an other forum i read that mysql and the description how to build the plugin only work till qt version 5.7 .
so i tried it with 5.7 and now it works! maybe there is a solution for higher versions, but for me it is enough