QMYSQL driver not loaded on mac

[tk421]

I'm also using Qt 5.9 on macOS and initially had a similar problem with the MySQL driver not working, and solved it using install_name_tool very much as was described above. In my case, MySQL was installed on my Mac with Homebrew.

However, now that I'm deploying the application I find that it works on my development Mac but not on other Macs. This makes sense: the libqsqlmysql.dylib in the app bundle, in the Plugins/sqldrivers directory depends on finding libmysqlclient.18.dylib in the location Homebrew uses. At the same time this doesn't make sense: how could this be the right way to do this?

I've read a lot of posts about this issue, but haven't found anything that addresses this issue: how do I configure the plugin so that it will work on other Macs, not just ones that happen to have MySQL installed in the way I have it installed?

Many users of my application don't even have MySQL installed. They are using my app to connect to a MySQL server on another server. I know this should be possible, because this app worked fine for my users for several years when I had it under Qt4. I'm just encountering this question because of a necessary upgrade to Qt5.

[SGaist]

Copy the library in your app bundle and use install_name_tool again to point the MySQL plugin to that library.

[Hasan Vaez]

Hi guys,
I have the same problem, but the above solutions and also all the solutions on the web do not work for me.
I am using Mac OS X Sierra, Qt5.9.1 installed at Home directory, Mysql 5.7.19 at /usr/local/mysql.
I would be pleased to help me to solve my problem on connection to QMSQL plugin.
I am wonder while all the new users has the same problem why Qt does not fix this bug which is seen in most of versions and claimed by many users. Half of the users' questions are about connecting to QMYSQL which is a real part of programming.
The error is:
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7
QSqlError("", "Driver not loaded", "Driver not loaded")

The stuffs I have done:
1- hasan-mac:/ hasan$ otool -L libqsqlmysql.dylib
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/objdump: 'libqsqlmysql.dylib': No such file or directory
2- linking the /usr/local/mysql/lib/libmysqlclient.20.dylib(and libmysqlclient.dylib) to /usr/lib
I think I could not run install_name_tool in the right way.
need your help please as I waste 2days searching the web for creating plugins and installing libs and so on...

regards,

[SGaist]

Hi and welcome to devnet,

1. This won't work because you are calling otool in some random place where libqsqlmysql.dylib is not located. Either give the full path to the plugin or cd into the sql plugins folder in your Qt installation and call that command again.

2. Likely for the same reason as number 1.

[Hasan Vaez]

Hi SQaist,
Thank you for your prompt reply.
The result on otool is:
MacBook-Pro:sqldrivers hasan$ otool -L /Users/hasan/Qt5.9.1/5.9.1/clang_64/plugins/sqldrivers/libqsqlmysql.dylib
/Users/hasan/Qt5.9.1/5.9.1/clang_64/plugins/sqldrivers/libqsqlmysql.dylib:
libqsqlmysql.dylib (compatibility version 0.0.0, current version 0.0.0)
@rpath/QtSql.framework/Versions/5/QtSql (compatibility version 5.9.0, current version 5.9.1)
@rpath/QtCore.framework/Versions/5/QtCore (compatibility version 5.9.0, current version 5.9.1)
/System/Library/Frameworks/DiskArbitration.framework/Versions/A/DiskArbitration (compatibility version 1.0.0, current version 1.0.0)
/System/Library/Frameworks/IOKit.framework/Versions/A/IOKit (compatibility version 1.0.0, current version 275.0.0)
/opt/local/lib/mysql55/mysql/libmysqlclient.18.dylib (compatibility version 18.0.0, current version 18.0.0)
/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 120.1.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1226.10.1)

[Hasan Vaez]

Tried to use the following command and problem solved.
install_name_tool -change /opt/local/lib/mysql55/mysql/libmysqlclient.18.dylib /usr/local/mysql/lib/libmysqlclient.20.dylib /Users/hasan/Qt5.9.1/5.9.1/clang_64/plugins/sqldrivers/libqsqlmysql.dylib

The thing I am worry about is when I will face to problem as we tricked to Qt to use libqslmysql.20.dylib instead of the the one in version 18 (libmysqlclient.18.dylib).
Mainly the problem is solved but it should not be OK. I am looking for a way to solve the problem in a correct way and do not want to use MACPORTS for installing the QMYSQL module. MACPORTS is a good installation package, but its size is more than 1GB in HDD and I'd prefer to use certified sourced like mysql.com website and qt.io website and so on...

[SGaist]

Then just install the package you want from whatever source suits you best and change the install_name_tool call accordingly.

[Hasan Vaez]

OK man. Thank you for your attention :)

[tk421]

@SGaist Thanks for putting me on the right path. I solved my issue and just wanted to post what I learned for others to benefit from:

I had used install_name_tool to tell my PlugIns/sqldrivers/libqsqlmysql.dylib to find the libmysqlclient.dylib that was on my Mac (in my case installed using Homebrew). That worked fine until I deployed to other Macs and then they got the "Driver Not Loaded" error. I needed libqsqlmysql.dylib to link to something inside the app bundle.

It turns out that macdeployqt was copying libmysqlclient.dylib into my Frameworks directory (the output clearly shows this) but still, it didn't work!

ls -l Frameworks/*dylib
 -rw-r--r--  1   1919816 22  libcrypto.1.0.0.dylib
 -rw-r--r--  1   3723040 22  libmysqlclient.dylib
 -rw-r--r--  1    375376 22  libssl.1.0.0.dylib

The first thing I noticed about this was that the file size of libmysqlclient.dylib was smaller after the copy:

/usr/local/Cellar/mysql/5.7.18/lib/libmysqlclient.dylib -> libmysqlclient.20.dylib
/usr/local/Cellar/mysql/5.7.18/lib/libmysqlclient.20.dylib  3773144

3723040 vs 3773144 bytes? I was convinced this was the problem and wasted hours trying to figure it out. I still don't understand this, but it isn't the problem. It was a red herring.

The real problem is that libmysqlclient.dylib depends on those other 2 dylib's copied into the Frameworks directory by macdeployqt: libssl.1.0.0.dylib and libcrypto.1.0.0.dylib. I ran otool -L on each in turn, and found that libssl.1.0.0.dylib was depending on a copy of libcrypto.1.0.0.dylib outside the app bundle (again the homebrew location).

So, I had to fix the dependency of two dylib's mid-way through my build steps:

make clean
qmake -config release
make
macdeployqt MyApp.app -dmg

'make' creates MyApp.app but the Frameworks and Plugins aren't put inside it until the first execution of macdeployqt. After that, I go in and fix the dependencies:

cd MyApp.app/Contents/Frameworks
install_name_tool -change /usr/local/Cellar/openssl/1.0.2l/lib/libcrypto.1.0.0.dylib @executable_path/../Frameworks/libcrypto.1.0.0.dylib libssl.1.0.0.dylib
cd ../PlugIns/sqldrivers
install_name_tool -change /usr/local/mysql/lib/libmysqlclient.dylib @executable_path/../Frameworks/libmysqlclient.dylib libqsqlmysql.dylib
cd ../../../..
rm -rf MyApp.dmg
macdeployqt MyApp.app -dmg

After fixing the dependencies with install_name_tool, I come back to the top-level directory and delete the DMG created by that run of macdeployqt. The second time macdeployqt is executed it does not replace MyApp.app. It just complains that much of what it was going to do is done already. For example:

File exists, skip copy: "MyApp.app/Contents/PlugIns/sqldrivers/libqsqlmysql.dylib"

The second execution of macdeployqt creates the DMG with the correctly-linked dylibs.

If someone else has a similar problem, don't just copy the above steps. Use the otool -L tool on the dylibs in your app bundle to see where the dependencies are expected to be, then check to see if they are actually there. If you are deploying your app bundle to somewhere else, consider which dylib's need to be copied into your app bundle and which you can count on being on the target Mac. Finally, use install_name_tool to fix your dependencies. Hope this helps!

[Amit Talbot]

im using qt 5.9 and isolated install on mysql 5.7.20 on mac this piece of code worked like charm for me

brew install mysql-connector-c

I already had MAMP installed.... and wanted to use the mysql from mamp running on port 8889 this code helped me to do that

```

db.setHostName("localhost");
db.setConnectOptions("UNIX_SOCKET=/Applications/MAMP/tmp/mysql/mysql.sock");
db.setDatabaseName("xxxxxx");
db.setUserName("root");
db.setPassword("root");
db.setPort(8889);

[edwinxxxx]

Hi, what i have done are as pervious.but it shows that

//-bash: /Users/lucas/Qt5.9.8/5.9.8/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: cannot execute binary file"

how can i fix it? thx for your help:)

[jsulm]

@edwinxxxx said in QMYSQL driver not loaded on mac:

/Users/lucas/Qt5.9.8/5.9.8/clang_64/plugins/sqldrivers/libqsqlmysql.dylib

You can't execute a library.
What are you trying to do?

[edwinxxxx]

@jsulm coz mysql driver can't be loaded in qt creator , i followed the directions above which has been proved that it was a successful way to solve the problem.but error happens.

[jsulm]

@edwinxxxx Please tell us the exact step your executing when you get that error message

[edwinxxxx]

@jsulm

[jsulm]

@edwinxxxx The last thig you did does not make sense: you're trying to execute a lib.
The first one was not successful - you called it in a wrong way. Take a look at its output ("Usage:"), it explains how to call it.
@SGaist - you're the Mac expert, can you take a look?

[edwinxxxx]

@jsulm thanks for your tips.i have wasted the whole day to solve it😂

[SGaist]

@edwinxxxx so it's now working correctly ?

[edwinxxxx]

@sgaist
platform: macos 10.14
mysql 8.0.17
qt 5.9.8

firstly i run

//otool -L libqsqlmysql.dylib

but it shows

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/objdump: 'libqsqlmysql.dylib': No such file or directory

how can i find the path like "opt/local..." on my machine?
thanks man.

[jsulm]

@edwinxxxx said in QMYSQL driver not loaded on mac:

how can i find the path like "opt/local..." on my machine?

find / -name libqsqlmysql.dylib