Qt Library 'mysql' is not defined - mysql

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.

Related

"Fatal error: 'EXTERN.h' file not found" while installing Perl modules

While trying to install Perl modules like JSON::XS or YAML::XS, i receive the same error:
XS.xs:1:10: fatal error: 'EXTERN.h' file not found
I use MacBook, xCode is up to date, everything else that could help is up to date too.
Since OS X El Capitan, Apple introduced System Integrity Protection which restricts writing to /usr/lib /usr/bin and other sensitive directories (even to root or sudo user) that are used by the installation of Perl bundled with the Operating System. This can cause issues when it comes to installing new modules and also if trying to install XS modules ( those linked to external C libraries ).
For this reason you should not consider the default Perl installation as a working development environment, especially if you are installing custom modules.
Check out this thread on PM and others. I had since El-Capitan managed to solve this before by manually building from tarball and adding a few params or environment variables to set the paths believing that it would be best to retain use of the system Perl but this is not the way to go. This makes your environment difficult to build but also brittle and sensitive to OS updates that may either break things in many different ways.
The best practice seems to be starting with a Perl using brew install perl and work in this environment, remembering to setup your bash_profile as directed by the installer.
Also worth remembering to do a brew link perl. If you receive warnings about this clobbering what looks like system Perl libraries don't worry - these are likely modules that were installed by you over the top and it will cause you less trouble to link over these. If you have concerns, make a note of which module installs will be cleared and re-install them once your environment is configured ( ie your module installer approach is configured using cpanm or sticking with the old perl -MCPAN -e shell etc)
This new Perl setup from brew eliminates the need to continuing running sudo which adds another layer of things that can go wrong as environment variables don't follow through and permission conflicts arise etc.
Finally to simplify package/module installation I suggest doing a brew install cpanminus. If you had previously already installed this, you can ensure the paths etc are configured by doing a brew reinstall cpanminus
If you want to take it another step further then you can install perlbrew as well which will give you the ability to run multiple versions of Perl as your user and configure these with their own libs and modules which can be very useful particularly if aligning with your production environment for testing etc.
One problem you may face if moving from system Perl to this kind of approach is needing to deal with any hangovers from installing things with sudo. It wis worth taking a little time to get all this set up right though and your issues going forward will be greatly reduced and you won't be left with that nagging feeling that you don't want to change anything for fear of it all breaking.
I have also come across a Perl Blog Article that suggests a fix for XS issues with perlbrew on Mojave
This Gist described updating your cpan shell install root though this shouldn't be necessary unless your cpan is stuck in an old config after taking steps above.
I've also raised this as a new issue on PerlMonks
After reading https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes#3035624 and installing the Additional headers via
sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /
I successfully compiled without the missing 'EXTERN.h' error
In order to follow the common advice I also tried with Perlbrew to install a dedicated development version of Perl. Especially with the advice in mind First, do not use the system Perl on MacOS. The installed version is for Apple, not for you (see the discussion here: https://www.perlmonks.org/?node_id=1224727).
Unfortunately, the following error occurred:
Test Summary Report
-------------------
porting/libperl.t (Wstat: 65280 Tests: 35 Failed: 0)
Non-zero exit status: 255
Parse errors: No plan found in TAP output
Files=2653, Tests=1217766, 708 wallclock secs (52.74 usr 9.40 sys + 395.38 cusr 49.90 csys = 507.42 CPU)
Result: FAIL
make: *** [test_harness] Error 1
##### Brew Failed #####
Therefore, I decided to install it the following way (and not following the advice due to the error).
Even after having the above mentioned macOS SDK headers already installed on Catalina (macOS 10.15.2) it didn't work for me. I faced the issue during the installation of the Perl module Mac-SystemDirectory-0.13. The following steps (by identifying the missing file in hope of having a more generic approach for more or less equivalent issues) did the trick:
Locate the header file (in this case EXTERN.h)
sudo find /Library -type f -name EXTERN.h
/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE/EXTERN.h
/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/System/Library/Perl/5.28/darwin-thread-multi-2level/CORE/EXTERN.h
/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE/EXTERN.h
Ensure the installed Perl version (here 5.18) match the header file:
perl -v | grep version
This is perl 5, version 18, subversion 4 (v5.18.4) built for darwin-thread-multi-2level
Export the path for the C-Compiler (note MacOSX10.15.sdk for Catalina and Perl Version 5.18)
export CPATH=/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE
Invoke the Makefile.PL with perl
perl Makefile.PL
BTW — For anybody who's still struggling with this, my workaround was:
bash% module="Sub::Util" # For example
bash% cpanm --configure-args="INC=-I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE" "$module"
Please try this
CPATH=$(dirname $(find /usr/local/Cellar/ -name EXTERN.h)) cpan JSON::XS
For Big Sur and perl 5.30, EXTERN.h is at /Library/Developer/CommandLineTools/SDKs/MacOSX11.3.sdk/System/Library/Perl/5.30/darwin-thread-multi-2level/CORE
I'm trying to upgrade CPAN itself and got that error. But I have /usr/bin/cpan and I can't write there so I have to tweak it to write the updated version to /usr/local/bin/cpan.
No promises, but yum install perl-devel worked for me.
As #huyz has helpfully pointed out, if you hit this error on a Mac, you don't have this option, even though this is probably your issue, and you need to follow one of the above methods of getting a version of Perl that isn't missing important chunks, as per other answers.
But if, dear reader, you hit this error on a linux host, as I did, then this might be an option for you.
Building on what E Lisse suggested, you might also have luck looking in
/System/Volumes/Data/Library/Developer/CommandLineTools/SDKs/
For example:
CPATH=$(dirname $(find /System/Volumes/Data/Library/Developer/CommandLineTools/SDKs/ -name EXTERN.h)) cpan JSON::XS
You could also find where EXTERN.h is located and add that to your shell by default, e.g. in your .bashrc or .zshrc file:
export CPATH=/System/Volumes/Data/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE/

unable to install percona mysql on linux centos 7 version

When we try to install percona MySQL using binary installation we are getting error as follows:
./mysql_install_db: error while loading shared libraries: libssl.so.1.1: cannot open shared object file: No such file or directory
[mysql#unvacp004 bin]$ ./mysql_install_db --basedir=/fs0/mysql/product/5.7.20/bin --defaults-file=/fs0/mysql/instance/dddd/conf/my.cnf --ledir=/fs0/mysql/product/5.7.20/bin/ --user=mysql
Have you tried the solution here?
https://bugs.launchpad.net/percona-server/+bug/1453395
It seems there are different tarballs which have different SSL library dependencies.
You probably use the wrong one.
Also make sure you have the libssl1.0.0 libssl-dev packages installed. This is for Ubuntu, for RHEL systems the packages might be called differently.

Compiling MySQL 5.7.20 in CentOS 7 Issues (A Lot)

I am trying to setup a MySQL server using CentOS (No GUI) and I need to switch to OpenSSL instead of YaSSL in order to have access to the encryption tools.
The issues happen when runing the cmake. At first I got the error that cmake was not able to find boost, I fixed this adding the parameter -DWITH_BOOST.
The cmake line is as follows.
cmake . -DWITH_READLINE=ON -DWITH_SSL=system -DWITH_BOOST=/usr/local/src/mysql-5.7.20/boost/
After the adjustment I ran again the CMAKE the I got several errors.
SSL Error, cmake can not find the OpenSSL files. I checked if the library was installed, I also downloaded the tar.gz file and decompress it and pointed the cmake to the folder, none of this worked.
Can not find NUMA libraries, again I checked and it is installed, at this point I ran the system update to check for everything but this did not solve the issue.
Can not find the ncurses, the same thing, is on the system but for some reason cmake is not able to find those.
Can not fin libaio, I didn't have this one installed, I installed, ran cmake again, and again cmake was not able to find it.
I been looking around, trying to figure out all this issues, I've been joining information from different websites but still not able to figure out this.
Thanks ahead to everyone for the help.
You're facing the dependencies hell with MySQL. If you don't really need to compile from the sources, you still can install with the RPM which is much easier. The RPM method is described here : https://dev.mysql.com/doc/mysql-yum-repo-quick-guide/en/
As you're asking a ready-to-go install from the sources, this is what I just did and it worked, on a fresh CentOS 7.4 minimal, 2 vcpus 3Gb :
yum group install -y 'Development Tools'
yum install -y cmake ncurses-devel curl
curl -Ovk https://cdn.mysql.com/Downloads/MySQL-5.7/mysql-5.7.20.tar.gz
tar zxf mysql-5.7.20.tar.gz
cd mysql-5.7.20
cmake . -DDOWNLOAD_BOOST=1 -DWITH_BOOST=$HOME/boost -DENABLE_DOWNLOADS=1
make -j2
make install
After that you need to configure it, add the startup scripts, and of course secure it. Here are some additional docs :
http://howtolamp.com/lamp/mysql/5.6/installing/
https://dev.mysql.com/doc/refman/5.7/en/mysql-secure-installation.html
Perhaps try make clean; cmake clean; ldconfig then run your cmake command. Sometimes the system can't find the shared libraries, and ldconfig refreshes the library search path. This helped once when I was compiling something (emscripten?) which required a lot of libraries which I was installing as compilation errors arose.
The make clean; cmake clean will ensure that the compiler isn't looking at the old library search path when you recompile.

How do I enable the intl extension in CakePHP?

I am using CakePHP 3 and MAMP Pro server for my project. When I am trying to bake the cake, this error shows up:
Fatal error: You must enable the intl extension to use CakePHP.
I have even included intl.so and extension=php_intl.dll in my php.ini file but couldn't figure out solution for this error.
this issue was happening to me some days ago. I had installed Ubuntu 18.04 and php 7.1.
I was trying to run the comman php cake.php bake in orden to use cakephp's console but I was getting the following error message:
You must enable the intl extension to use CakePHP.
This extension (intl) was installed for php 7.1 (php7.1-intl) but this message was appearing every time I used php cake.php bake
After some google searches, I saw that I have to install the extension but with the following command:
sudo apt-get install php-intl
The same issue happened with mbstring extension, I used the command:
sudo apt-get install php-mbstring
then I restarted the apache server with:
sudo service apache2 restart
It's difficult to pinpoint exactly what's wrong without seeing your system setup. However based on what was said in the question, you may be setting up the intl extension incorrectly.
First off, if your OS is Linux/macOS and the PHP extension is a shared library (i.e. has a .so extension) then the php.ini entry should be extension=intl.so not extension=php_intl.dll. Also make sure the intl.so file is in the directory configured under the ini entry extension_dir. Otherwise make sure the extension ini entry is fully qualified (e.g. extension=/path/to/extension/dir/intl.so).
If you are using a Linux OS that has a package manager such as Debian/Ubuntu, you may be able to more easily install the extension for the PHP packaged for that distro. For example, in Ubuntu/Debian the package php5-intl provides the intl extension for PHP5 (I assume it's something similar for PHP7 if you've enabled those repos).
If you build PHP from source, you can try bundling the extension into your PHP. See the instructions from the manual.
I faced the same issue.
I added extension="php_intl.dll" in php.ini and restarted the Apache server.
Now it is working.
I had the same issue. After starting from scratch, I did :
$ brew install php
$ composer install && composer update && composer dump-autoload --optimize
$ composer self-update && composer create-project --prefer-dist cakephp/app:^3.8 cms
$ cd cms
$ bin/cake server
And it was working !

Using MySQL in R for Windows

How to use MySQL in R (statistic language) for Windows (7)?
There is no problems then using linux:
install.packages('RMySQL')
library(RMySQL)
...
But I found no such package for Windows on CRAN. There is only note about this fact.
I found package for version 2.10, but it is not usable in 2.12.1.
Also tried
install.packages("RMySQL", type="source")
but got an error :
* installing *source* package 'RMySQL' ...
ERROR: configuration failed for package 'RMySQL'
* removing 'C:/.../R/win-library/2.12/RMySQL'
Is there any way to connect to MySQL database from R in windows?
Found solution with help of ran2, who gave me link to common question. The basic process is described here, but there are several hints, So I will describe the whole solution (please change the R version and paths if needed):
Install latest RTools from here
install MySQL or header and library files of mysql
create or edit file C:\Program Files\R\R-2.12.1\etc\Renviron.site and add line like MYSQL_HOME=C:/mysql (path to your mysql files)
copy libmysql.lib from mysql/lib to mysql/lib/opt to meet dependencies.
copy libmysql.dll to C:\Program Files\R\R-2.12.1\bin or to windows/system32 directory.
run install.packages('RMySQL',type='source') and wait while compilation will end.
Thanks to all who tried to answer.
possible duplicate. However, my suggestions is to try WAMP which comes as a one click install. Admittedly you get more than you need (webserver) but the MySQL installation runs pretty well.
You need to install the MySQL headers and libraries, as explained in the installation instructions. Please do read the documentation before turning to SO.