［Linux笔记］Ubuntu14.04+QT5.2配置mysql

安装qt：

• 官网下载qt5.2.1：qt-opensource-linux-x64-5.2.1.run
• 直接命令行运行：./qt-opensource-linux-x64-5.2.1.run
• 选择安装路径：（我选择的是/home/myname/Qt）默认为/home/yourPCname/Qt5.2.1
• 一步一步安装，选择组建时记得勾选“Source Components”，否则后续重新编译sql的plugin可能需要重装qt

安装mysql，编写简单测试程序：

#include <QApplication>
#include <QtSql>
#include <QDebug>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL", "connA");
    db.setHostName("localhost");
    db.setDatabaseName("mysql");
    db.setUserName("root");
    db.setPassword("zymysql");
    if(db.open()) {
        qDebug() << "connected!" << endl;
        exit(0);
    } else {
        qDebug() << " failed!" << endl;
        exit(0);
    }

    return a.exec();
}

编译运行，提示错误：

QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QPSQL QPSQL7

1.查看sqldriver的依赖关系：

$cd ~/Qt/5.2.1/gcc_64/plugins/sqldrivers
$ldd libqsqlmysql.so
#得到以下：
linux-vdso.so.1 =>  (0x00007ffe607ac000)
	libmysqlclient_r.so.16 => not found
	libQt5Sql.so.5 => /home/sharon/Qt/5.2.1/gcc_64/plugins/sqldrivers/./../../lib/libQt5Sql.so.5 (0x00007f4862374000)
	libQt5Core.so.5 => /home/sharon/Qt/5.2.1/gcc_64/plugins/sqldrivers/./../../lib/libQt5Core.so.5 (0x00007f4861ca6000)
	libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f48619a2000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f48615dd000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f48613bf000)
	libicui18n.so.51 => /home/sharon/Qt/5.2.1/gcc_64/plugins/sqldrivers/./../../lib/libicui18n.so.51 (0x00007f4860fa6000)
	libicuuc.so.51 => /home/sharon/Qt/5.2.1/gcc_64/plugins/sqldrivers/./../../lib/libicuuc.so.51 (0x00007f4860c20000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f4860a1c000)
	libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f486081a000)
	librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f4860612000)
	libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f486030a000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f4860004000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f485fdee000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f48627c6000)
	libicudata.so.51 => /home/sharon/Qt/5.2.1/gcc_64/plugins/sqldrivers/./../../lib/libicudata.so.51 (0x00007f485e6a5000)
	libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f485e467000)

2，查看安装的mysql的版本：

$ dpkg --get-selections | grep mysql
#得到以下：
ctions | grep mysql
libdbd-mysql-perl				install
libmysqlclient-dev				install
libmysqlclient18:amd64				install
mysql-client					install
mysql-client-5.5				install
mysql-client-core-5.5				install
mysql-common					install
mysql-server					install
mysql-server-5.5				install
mysql-server-core-5.5				install

错误点在于：libmysqlclient_r.so.16 => not found，需要的是版本为16，安装的版本为18.

解决方案：为其重新编译sqldriver。

#进入到qt的源码目录下的此目录：
$cd ~/Qt/5.2.1/Src/qtbase/src/plugins/sqldrivers/mysql
#使用qmake编译：
$ ~/Qt/5.2.1/gcc_64/bin/qmake "INCLUDEPATH+=/usr/local/include" "LIBS+=-L/usr/local/lib -lmysqlclient_r" mysql.pro
$make
$make install
#再进入到gcc目录下查看libqsqlmysql.so的依赖关系：
$cd ~/Qt/5.2.1/gcc_64/plugins/sqldrivers
$ldd libqsqlmysql.so
#依赖关系成功建立：
	linux-vdso.so.1 =>  (0x00007fff193b2000)
	libmysqlclient.so.18 => /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18 (0x00007fc367f2a000)
	libQt5Sql.so.5 => /home/sharon/Qt/5.2.1/gcc_64/lib/libQt5Sql.so.5 (0x00007fc367cea000)
	libQt5Core.so.5 => /home/sharon/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5 (0x00007fc36761c000)
	libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fc367318000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fc366f53000)
	libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fc366d3a000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fc366b36000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fc366918000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fc366612000)
	libicui18n.so.51 => /home/sharon/Qt/5.2.1/gcc_64/lib/libicui18n.so.51 (0x00007fc3661f9000)
	libicuuc.so.51 => /home/sharon/Qt/5.2.1/gcc_64/lib/libicuuc.so.51 (0x00007fc365e73000)
	libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007fc365c71000)
	librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fc365a69000)
	libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007fc365761000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fc36554b000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fc368674000)
	libicudata.so.51 => /home/sharon/Qt/5.2.1/gcc_64/lib/libicudata.so.51 (0x00007fc363e02000)
	libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007fc363bc4000)

重新编译运行，成功！