QT 5.7 MySQL驱动程序未加载

Question

There are quite a few questions/answers relating to this topic but I have tried all the posted solutions:

System Info :

• Ubuntu Gnome 16.10 x86-64

• MYSQL Version:

  mysql Ver 14.14 Distrib 5.7.15, for Linux (x86_64) using EditLine wrapper

Note: Each attempt ends up with this error message

QSqlDatabase: QMYSQL driver not loaded

QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QPSQL QPSQL7

Tried:

Installing Packages for QT 4:

apt-get install libqt4-sql-mysql

Installing Packages for QT 5:

apt-get install libqt5sql5-mysql

Removing and installing libmysqlclient-dev

$ sudo apt-get purge libmysqlclient-dev
$ sudo apt-get install libmysqlclient-dev

Tried creating symlink as shown below:

#locate libmysqlclient file

$ locate libmysqlclient

/usr/lib/x86_64-linux-gnu/libmysqlclient.so.20
/usr/lib/x86_64-linux-gnu/libmysqlclient.so.20.3.2
/usr/share/doc/libmysqlclient20
/usr/share/doc/libmysqlclient20/NEWS.Debian.gz
/usr/share/doc/libmysqlclient20/changelog.Debian.gz
/usr/share/doc/libmysqlclient20/copyright
/var/cache/apt/archives/libmysqlclient20_5.7.15-0ubuntu2_amd64.deb
/var/lib/dpkg/info/libmysqlclient20:amd64.list
/var/lib/dpkg/info/libmysqlclient20:amd64.md5sums
/var/lib/dpkg/info/libmysqlclient20:amd64.shlibs
/var/lib/dpkg/info/libmysqlclient20:amd64.symbols
/var/lib/dpkg/info/libmysqlclient20:amd64.triggers

#cd to the dir, and create link
$ cd /usr/lib/x86_64-linux-gnu
$ sudo ln -s /usr/lib/x86_64-linux-gnu/libmysqlclient.so.20 libmysqlclient_r.so

this one I just incase

$ sudo ln -s /usr/lib/x86_64-linux-gnu/libmysqlclient.so.20 libmysqlclient_r.so 

Contents of Plugin directory:

ll /opt/qt/QT-5.7/5.7/gcc_64/plugins/sqldrivers/
total 988
drwxrwxr-x 1 cx cx     84 Oct 17 15:58 ./
drwxrwxr-x 1 cx cx    504 Oct 17 15:58 ../
-rwxr-xr-x 1 cx cx 851008 Jun 10 11:10 libqsqlite.so*
-rwxr-xr-x 1 cx cx  75424 Jun 10 11:10 libqsqlmysql.so*
-rwxr-xr-x 1 cx cx  79368 Jun 10 11:10 libqsqlpsql.so*

Project Info:

Added to .pro file:

QT += sql

Code:

#include <QtSql>
#include <QSqlDriver>
#include <qsqldatabase.h>
#include <QSqlError>
#include <QPluginLoader>
#include <cstdio>

using namespace std;

//some irrelevant project code in between

QString rootPass = getRootPassword();
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
    db.setHostName("localhost");
    //    db.setDatabaseName(DBName);
    db.setUserName("root");
    db.setPassword(rootPass);

    if (!db.isValid()){
        QSqlError err = db.lastError();
        cout << endl << "!DB ERROR: "<< err.text();
        cout.flush();
    }

    //qsqlerror err: unused4 : 21985
    //qsqlerror err: unused3 : 2757134240 (2757134240)

    if (db.open()){
        //do things to database
    }
    else
    {
        cout << "error opening database" << endl;
    }

In my project, I have tried:

    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");

and

    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL3");

just in case, no luck

I have also copied the libmysqlclient.so file to my plugins directory, also did not work (tried this incase of a library path missing,etc.)

I have no idea how to continue further, any suggestions would be helpful

Answer 1

Well the solution was not easy but it had to be done.

I had to recompile the driver!

use this as a guide.