I have wasted around 6 hours trying to get MySQL working with Qt following all sorts of instructions from the web. I want to cut my wrist off now!
Does anyone have a simple and a verbose explanation of how to install QMYSQL driver into Qt?
I have Mac 10.6 and I am a beginner n00b.
Your help will be appreciated from the bottom of my heart!
Sana.
EDIT:
I get the following files when I do the grep, so among these just for kicks I copied libqsqlmysql.dylib into all of the folders, but still I don't get to compile... I get an error saying that QSqlDatabase: QMYSQL driver not loaded
/Library/Application Support/DivX/QtPlugins/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Assistant.app/Contents/PlugIns/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Designer.app/Contents/PlugIns/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Desktop/Qt/4.8.0/gcc/plugins/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Desktop/Qt/4.8.0/gcc/plugins/sqldrivers/libqsqlite_debug.dylib
/Users/pfn368/QtSDK/Desktop/Qt/474/gcc/plugins/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Desktop/Qt/474/gcc/plugins/sqldrivers/libqsqlite_debug.dylib
/Users/pfn368/QtSDK/Madde/sysroots/harmattan-arm-sysroot/usr/lib/qt4/plugins/sqldrivers/libqsqlite.so
/Users/pfn368/QtSDK/Madde/sysroots/harmattan-nokia-arm-sysroot/usr/lib/qt4/plugins/sqldrivers/libqsqlite.so
/Users/pfn368/QtSDK/Maemo/4.6.2/sysroots/fremantle-arm-sysroot-20.2010.36-2-slim/usr/lib/qt4/plugins/sqldrivers/libqsqlite.so
/Users/pfn368/QtSDK/Qt Creator.app/Contents/MacOS/qmlpuppet.app/Contents/PlugIns/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Qt Creator.app/Contents/PlugIns/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/QtSources/4.8.0/plugins/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/QtSources/4.8.0/plugins/sqldrivers/libqsqlite_debug.dylib
/Users/pfn368/QtSDK/Simulator/Application/simulator.app/Contents/PlugIns/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Simulator/Qt/gcc/plugins/sqldrivers/libqsqlite.dylib
/Users/pfn368/QtSDK/Simulator/Qt/gcc/plugins/sqldrivers/libqsqlite_debug.dylib
This is my .pro file
QT += sql core gui\
network
TARGET = mini-stock-exchange
TEMPLATE = app
SOURCES += ./src/main.cpp\
./src/mainwindow.cpp
HEADERS += ./header/mainwindow.h
FORMS += ./ui/mainwindow.ui
My includes
#include "./header/mainwindow.h"
#include "ui_mainwindow.h"
#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlQuery>
#include <QFile>
#include <QtSql/QSqlError>
#include <qsqldatabase.h>
#include <QtCore>
#include <QtSql>
Code to call the database
QSqlDatabase defaultDB = QSqlDatabase::addDatabase("QMYSQL3");
if ( !defaultDB.isValid() ) {
qWarning( "Failed to connect to the database driver" );
}
defaultDB.setDatabaseName( "nicu" );
defaultDB.setUserName( "root" );
defaultDB.setPassword( "root" );
defaultDB.setHostName( "http://localhost:8889" );
First download the Qt SDK sources and a version of the mysql server sources, extract them both.
Create Symlinks to MySQL's lib files:
sudo ln -s /Users/simon/Downloads/mysql-5.6.11-osx10.7-x86_64/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.dylib
sudo ln -s /Users/simon/Downloads/mysql-5.6.11-osx10.7-x86_64/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient_r.dylib
sudo ln -s /Users/simon/Downloads/mysql-5.6.11-osx10.7-x86_64/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
sudo ln -s /Users/simon/Downloads/mysql-5.6.11-osx10.7-x86_64/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient_r.18.dylib
After that cd to your extracted Qt SDK into the folder /Users/simon/Downloads/qt-everywhere-opensource-src-4.8.4/src/plugins/sqldrivers/mysql
Build the Libraries:
qmake -spec macx-g++ -o Makefile "INCLUDEPATH+=/Users/simon/Downloads/mysql-5.6.11-osx10.7-x86_64/include" "LIBS+=-L/usr/lib -lmysqlclient_r" mysql.pro
make
mv libqsqlmysql_debug.dylib libqsqlmysql.dylib
cp -R libqsqlmysql.dylib /Developer/Applications/Qt/plugins/sqldrivers/
After that you should be able to use the QMYSQL plugin. Check if the library was loaded correctly with this line of code (put it in some constructor so that you'll the the output right after starting the app):
qDebug() << QCoreApplication::libraryPaths();
qDebug() << QSqlDatabase::drivers();
For e.g. my output looks like this now:
("/Developer/Applications/Qt/plugins", "/Users/simon/Coding/qt4c/build-SQLtable-Desktop-Debug/SQLtable.app/Contents/MacOS")
("QSQLITE", "QMYSQL3", "QMYSQL", "QODBC3", "QODBC", "QPSQL7", "QPSQL")
The Qt 4 packages from Mac Homebrew have an option to install mysql-drivers as a Qt Plugin for default (it's not a default option, that's why you are missing this).
Download and install Mac OS X Homebrew software as described here: http://brew.sh.
After installing homebrew, remove the previously Qt4 installation.
If you have installed it using brew just type on the terminal:
$ brew remove qt4
To install it with mysql support run:
$ brew install qt4 --with-mysql
And everytime you need to install a package with some options in brew but you don't know the supported options just type:
$ brew options FORMULA_NAME
And it will show all the build options available for the given formula.
Sana, I'm going to try save that hand, alrighty.
First you need the Qt everywhere opensource package from the internets. I've got no idea what version of Qt you're running, but you need the same version as your core install.
Second, you get into the source package and go through the plugins until you find the sql drivers and the mysql plugin. At this stage make sure you know what path your mysql libs and includes are on, as you'll need them.
Third, modify the .pro for the mysql plugin and add your MySql include path to INCLUDEPATH+= and the libs to....LIBS+=
Fourth, run qmake on the .pro to generate a Makefile, then make the make file and you'll have some pretty little .dylib files looking at you with eyes full of joy.
Fifth, the fun part, you need to find where the other plugins are, and this varies system by system. Quickest way to find them is in Terminal type 'sudo find / | grep libqsqlite' and it'll give you the location of that, and that's your Qt sqldrivers plugin directory. Copy the dylib you just built into there.
And that should do it. It's worked for me on quite a few builds and rebuilds.
Related
I have a problem with Qt connecting with MySql, when i run this code
QSqlDatabase DBObject = QSqlDatabase::addDatabase("QMYSQL");
DBObject.setHostName("localhost");
DBObject.setDatabaseName("SingleDB");
DBObject.setUserName("root");
DBObject.setPassword("abc123");
bool ok = DBObject.open();
and I got this... QSqlDatabase: QMYSQL driver not loaded
I Have already done this also:
sudo apt-get install libmysqlclient
and
/home/wrm/Qt/5.12.3/gcc_64/bin/qmake "INCLUDEPATH+=/usr/local/include" "LIBS+=-L/usr/local/lib -lmysqlclient_r" mysql.pro
and here i have this error: Project ERROR: Library 'mysql' is not defined
Any idea?
Perhaps you need to install mysql-devel.
According to the Qt Docs QMYSQL for MySQL 4 and higher:
How to Build the QMYSQL Plugin on Unix and macOS
You need the MySQL header files, as well as the shared library libmysqlclient.so. Depending on your Linux distribution, you may need to install a package which is usually called "mysql-devel".
Google doesn't have a readily available answer, so answering this old question:
Aside from needing development files as pointed above (like apt install libmysqlclient-dev), you need to generate a config:
# Just for making my snippet work. Feel free to hardcode paths.
export QTDIR=/home/you/Qt/
export QTVERSION=5.9.5
cd $QTDIR/$QTVERSION/Src/qtbase/src/plugins/sqldrivers
$QTDIR/$QTVERSION/gcc_64/bin/qmake sqldrivers.pro
cd mysql
make
make install # if you want; it installs it in the bin dir of $QTVERSION
In the past, this was not necessary for Qt 5.5 (where I did this last time).
On a side note, there is no longer a special thread-safe version of libmysqlclient (libmysqlclient_r). It's just one one. Last time I ran into that link error, I just edited the generate Makefile to use the non-_r.
I am trying to install libde265 from source but one of its dependencies is giving me problems. I also installed this depedency from source but I converted it to an rpm package before completing installation.
When I look for the location of this library I get:
$ whereis libvideogfx
libvideogfx: /usr/local/lib/libvideogfx.la /usr/local/lib/libvideogfx.a /usr/local/lib/libvideogfx.so
The flags I have added to the ./configure command such as LIBS are not working and I don't know the root of the problem.
I know that I can install Cuda with the following:
wget http://developer.download.nvidia.com/compute/cuda/7_0/Prod/local_installers/cuda_7.0.28_linux.run
chmod +x cuda_7.0.28_linux.run
./cuda_7.0.28_linux.run -extract=`pwd`/nvidia_installers
cd nvidia_installers
sudo ./NVIDIA-Linux-x86_64-346.46.run
sudo modprobe nvidia
sudo ./cuda-linux64-rel-7.0.28-19326674.run
Just wondering if I can install Cuda without root?
Thanks,
Update The installation UI for 10.1 changed. The following works:
Deselect driver installation (pressing ENTERon it)
Change options -> root install path to a non-sudo directory.
Press A on the line marked with a + to access advanced options. Deselect create symbolic link, and change the toolkit install path.
Now installation should work without root permissions
Thank you very much for the hints in the question! I just want to complete it with an approach that worked for me, also inspired in this gist and that hopefully helps in situations where a valid driver is installed, and installing a more recent CUDA on Linux without root permissions is still needed.
TL;DR: Here are the steps to install CUDA9+CUDNN7 on Debian, and installing a pre-compiled version of TensorFlow1.4 on Python2.7 to test that everything works. Everything without root privileges and via terminal. Should also work for other CUDA, CUDNN, TensorFlow and Python versions on other Linux systems too.
INSTALLATION
Go to NVIDIA's official release web for CUDA (as for Nov. 2017, CUDA9 is out): https://developer.nvidia.com/cuda-downloads.
Under your Linux distro, select the runfile (local)option. Note that the sudo indication present in the installation instructions is deceiving, since it is possible to run this installer without root permissions. On a server, one easy way is to copy the <LINK> of the Download button and, in any location of your home directory, run wget <LINK>. It will download the <INSTALLER> file.
Run chmod +x <INSTALLER> to make it executable, and execute it ./<INSTALLER>.
accept the EULA, say no to driver installation, and enter a <CUDA> location under your home directory to install the toolkit and a <CUDASAMPLES> for the samples.
Not asked here but recommended: Download a compatible CUDNN file from the official web (you need to sign in). In my case, I downloaded the cudnn-9.0-linux-x64-v7.tgz, compatible with CUDA9 into the <CUDNN> folder. Uncompress it: tar -xzvf ....
Optional: compile the samples. cd <CUDASAMPLES> && make. There are some very nice examples there and a very good starting point to write some CUDA scripts of yourself.
(If you did 5.): Copy the required files from <CUDNN> into <CUDA>, and grant reading permission to user (not sure if needed):
cp -P <CUDNN>/cuda/include/cudnn.h <CUDA>/include/
cp -P <CUDNN>/cuda/lib64/libcudnn* <CUDA>/lib64
chmod a+r <CUDA>/include/cudnn.h <CUDA>/lib64/libcudnn*
Add the library to your environment. This is typically done adding this following two lines to your ~/.bashrc file (in this example, the <CUDA> directory was ~/cuda9/:
export PATH=<CUDA>/bin:$PATH
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:<CUDA>/lib64/
FOR QUICK TESTING OR TENSORFLOW USERS
The quickest way to get a TensorFlow compatible with CUDA9 and CUDNN7 (and a very quick way to test this) is to download a precompiled wheel file and install it with pip install <WHEEL>. Most of the versions you need, can be found in mind's repo (thanks a lot guys). A minimal test that confirms that CUDNN is also working involves the use of tf.nn.conv2d:
import tensorflow as tf
x = tf.nn.conv2d(tf.ones([1,1,10,1]), tf.ones([1,5,1,1]), strides=[1, 1, 1, 1], padding='SAME')
with tf.Session() as sess:
sess.run(x) # this should output a tensor of shape (1,1,10,1) with [3,4,5,5,5,5,5,5,4,3]
In my case, the wheel I installed required Intel's MKL library, as explained here. Again, from terminal and without root users, this are the steps I followed to install the library and make TensorFlow find it (reference):
git clone https://github.com/01org/mkl-dnn.git
cd mkl-dnn/scripts && ./prepare_mkl.sh && cd ..
mkdir -p build && cd build
cmake -D CMAKE_INSTALL_PREFIX:PATH=<TARGET_DIR_IN_HOME> ..
make # this takes a while
make doc # do this optionally if you have doxygen
make test # also takes a while
make install # installs into <TARGET_DIR_IN_HOME>
add the following to your ~/.bashrc: export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:<TARGET_DIR_IN_HOME>/lib
Hope this helps!
Andres
You can install using conda with the following command.
conda install -c anaconda cudatoolkit
But you need to have prior accesss to the device(GPU).
EDIT : If you are finding error in anaconda repository then change the repository to conda-forge which is frequently updated.
conda install -c conda-forge cudatoolkit
You can install CUDA and compile programs, but you won't be able to run them for a lack of device access.
How do I load qmysql driver in Qt? I have the following code that produces these results:
("QSQLITE", "QMYSQL", "QMYSQL3")
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3
Any suggestions on how to load it?
We should check our driver first
$ cd /opt/Qt5.2.1/5.2.1/gcc_64/plugins/sqldrivers
then we can find some files
Use the command below to check library
$ ldd libqsqlmysql.so
if you find the problem libmysqlclient_r.so.16 => not found it may be the library-dependency problem.
After I did a little research on the Internet, there is a way would be easy.
$ cd /usr/lib/x86_64-linux-gnu
if you find libmysqlclient_r.so.18,
$ cp libmysqlclient_r.so.18 libmysqlclient_r.so.16
ok it worked just by copying the sqldrivers folder to my debug folder and it worked!
You could try diagnosing the issue with strace - it seems like the QMYSQL driver might need some run-time library dependencies to work.
On Windows (see as directory structure):
the_qt_app.exe
libmysql.dll
sqldrivers/qsqlmysql4.dll
You can use QPluginLoader to get some better error message.
When I had the same problem with the MySQL driver the message was something like "The version was compiled with other options than this Qt version".
It seemed like the Qt sources, that shipped with the Qt SDK at that time, were not compatible with its binaries.
After downloading the Qt sources and compiling my own version of Qt and the MySQL driver, the problem was gone.
EDIT: Some sample code.
QPluginLoader loader;
loader.setFileName("/Users/niklaswulf/QtSDK/Qt/4.8.4/plugins/sqldrivers/libqsqlite_debug.dylib");
qDebug() << loader.load();
qDebug() << loader.errorString();
loader.setFileName("/Users/niklaswulf/QtSDK/Qt/5.0.1/5.0.1/clang_64/plugins/sqldrivers/libqsqlite_debug.dylib");
qDebug() << loader.load();
qDebug() << loader.errorString();
When compiling against 5.0.1 this is the output:
false
"The file '/Users/niklaswulf/QtSDK/Qt/4.8.4/plugins/sqldrivers/libqsqlite_debug.dylib' is not a valid Qt plugin."
true
"Unknown error"
I also found the old message:
The plugin '/path/to/some/libqsqlmysql.dylib' uses incompatible Qt library. Expected build key "macosx macx-cocoa g++-4 full-config", got "macosx macx-cocoa g++-4 no-pkg-config"
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3
The same problem I faced in fedora20 (64-bit) with Qt-5.2.0, and then follow steps:
$ cd /opt/Qt5.2.0/5.2.0/gcc_64/plugins/sqldrivers
$ ls
libqsqlite.so libqsqlmysql.so
Use the command below to check library dependency:
$ ldd libqsqlmysql.so
I find the problem:
libmysqlclient_r.so.16 => not found
It may be the library-dependency problem. so solve this problem:
Linking of the library file:
$ ln -s libmysqlclient_r.so.16.0.0 libmysqlclient_r.so
and again:
$ ln -s libmysqlclient_r.so.16.0.0 libmysqlclient_r.so.16
Now its work for me.
All the best
Got the same problem and some Google research and intuition finally solved it.
Using Qt5.9.1 and Ubuntu 17.10
First, check if the error of libmysqlclient.so.18 => not found is present
:~/Qt5.9.1/5.9.1/gcc_64/plugins/sqldrivers$ ldd libqsqlmysql.so
Second, search where is libmysqlclient
:/$ locate libmysqlclient
Third, go to the folder where libmysqlclient is present and there make the link
:/usr/lib/x86_64-linux-gnu$ sudo ln -s libmysqlclient.so.20 libmysqlclient.so.18
and check the link made before with
ls -alh | grep libmysql
At that moment, none of those solved for me, and i decided to look further in synaptic packages, and realize that libqt5sql5-mysql version 5.9.1 was not installed, so installing it solved the problem but i still have a message when doing ldd
./libqsqlmysql.so: /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18: version `libmysqlclient_18' not found (required by ./libqsqlmysql.so)
after that, found some links that guide me to a real solution, here are them, if you wanna know whats happening
i downloaded the library stated in the third link and worked like a charm. hope it helps!
https://www.unix.com/unix-for-advanced-and-expert-users/107611-difference-between-libsqlclient-so-libsqlclient_r-so.html
http://www.tango-controls.org/community/forum/c/general/installation/ubuntu-1604-problem-installing-from-source-code-libmysqlclient-replaces-libmysqlclient_r/
https://superuser.com/questions/1101426/installing-libmysqlclient18-on-ubuntu-16-04?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa&newreg=9c558283c488461aaf597ef1132e4ca0
Here a couple of very nice links on this issue:
making the plugins manually on Unix-based systems (from Qt documentation):
http://qt-project.org/doc/qt-5/sql-driver.html
a very well-written link specifically on this issue (Do not forget to install the Qt from source, this can be done by either checking the corresponding (hidden) box in the first step while installing from the .run executable or by downloading the 'qt-everywhere-opensource-src' version):
http://adamcavendish.is-programmer.com/posts/40431.html
Enjoy,
Peyman
My answer:
QSqlDatabase db(QSqlDatabase::addDatabase("QMYSQL"));
db.setDatabaseName("dbname");
db.setHostName("localhost");
db.setUserName("usernm");
db.setPassword("password");
if (db.open())
{
qDebug() << "SUCCESS!";
db.close();
}
I'm trying to use Ruby with the MySQL that comes with MAMP, but there is a problem with the headers not being installed (or something like that).
Someone referred me to the tutorial copied below but I can't get it to work. When I put in the first line ./configure... it says no such directory.
1) One question in particular is, it says, "copy the MySQL source file (mysql-5.1.37.tar.gz) to somewhere on your hard drive." I don't know if by installing MAMP I have already done this step or not. If not, then I don't know what to do.
2) I also don't know what it means when it says "untar" the source file and "cd"...If MAMP is installed, has it been untarred already?
3) Also, do would I just open the terminal and start this code, or do I have to go into Mysql?
I wonder if anyone can tell me how to adapt it. Here are 2 other pieces of information about my installation that might be helpful.
a). MySQL is set up on port 8889 on my computer.
b) Also when I enter "which mysql" in the command line, it responds with "/usr/local/mysql/bin/mysql."
Please help if you can. Thanks.
Download the latest MAMP dmg file.
Download the 1.8.2 (or whichever the latest one you could find) components file from this page.
Unzip, mount the dmg, then copy the MySQL source file (mysql-5.1.37.tar.gz) to somewhere on your hard drive.
Untar the MySQL source file, and `cd` to the source file directory.
Compile the library:
$ ./configure --with-unix-socket-path=/Applications/MAMP/tmp/mysql/mysql.sock --without-server --prefix=/Applications/MAMP/Library
$ make -j2
Copy the compiled libraries into MAMP:
$ cp libmysql/.libs/*.dylib /Applications/MAMP/Library/lib/mysql
Copy the MYSQL headers into MAMP:
$ mkdir /Applications/MAMP/Library/include
$ cp -R include /Applications/MAMP/Library/include/mysql
Install the Ruby MySQL Gem, on Snow Leopard:
$ sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/Applications/MAMP/Library/bin/mysql_config
On Leopard:
$ sudo env ARCHFLAGS="-arch i386" gem install mysql -- --with-mysql-config=/Applications/MAMP/Library/bin/mysql_config
Enjoy!
EDIT # 2009-11-23: If you’re still experiencing problems (perhaps with RVM), try adding “/Applications/MAMP/Library/bin/” to your $PATH in “~/.bash_profile”.
You should probably follow the tutorial in this link. It is updated for MAMP 1.9.5 with mysql2. A couple of changes have been made to the new MAMP version.
http://blog.mirotin.net/?p=35
Furthermore the tar file you need can be found at this link. Download the MAMP_components_1.9.5.dmg file.
http://sourceforge.net/projects/mamp/files/mamp/1.9.5/
Finally got through this with this blog post: http://newfangled.me/installing-mamp-and-rails-on-a-mac/
Here's the archived version of that incase it goes offline http://web.archive.org/web/20130728130916/http://newfangled.me/installing-mamp-and-rails-on-a-mac
The other answer's reference 404s for me. http://blog.mirotin.net/?p=35
I'd been struggling with this for a while myself.