Connection to MySQL database (driver not loaded) with QT5.5 in CentOS7 (64-bit)

Connection to MySQL database (driver not loaded) with QT5.5 in CentOS7 (64-bit)

To connect to MySQL using qt, you need to share the driver of libqsqlmysql. so. The path is under the plugin/sqldrivers directory. At first glance, it is available, but it is not.

Use the ldd command to analyze libmysqlclient_r.so.16 => not found. Later, it is obvious that libmysqlclient_r.so.16 lacks another shared library. They are dependent and solve this problem to connect qt to the mysql database. The version of the shared library under my/usr/lib64/is higher than that of libmysqlclient. so.18. I thought of a speculative idea to create a symbolic link using ln. However, this is useless.

I can't help but laugh at the fact that QT5.5 was downloaded from the official website. It depends on a lower version. You can't help but be lazy during compilation. It is estimated that they copied libqsqlmysql directly from a lower version. so, no way? Apparently not. Open the qt official website to download the source code and compile it by yourself. Download process skipped, very good to find the http://download.qt.io/official_releases/qt/5.4/5.4.2/submodules/ (no source code qt5.5), find the qtbase about 60 M. The path of the MySql driver is qtbase/src/plugins/sqldrivers/mysql /.
• Qmake
• Make

However, the dynamic library cannot be found in the make process:

/Usr/bin/ld: cannot find-lz
/Usr/bin/ld: cannot find-lssl
/Usr/bin/ld: cannot find-lcrypto

The first one is that zlib-devel is not installed, and yum install zlib-devel is used directly.

The third item cannot be found. Solution:/usr/lib64/create a symbolic link.

Ln-s libssl. so.1.0.1e libssl. so

Ln-s libcrypto. so.1.0.1e libcrypto. so

Make again. Of course, this is not complete yet. Use the new libqsqlmysql. so to replace the old one. This is all done.

View again:

[Sqldrivers] ldd libqsqlmysql. so
Linux-vdso.so.1 => (0x00007fff2d5fe000)
Libmysqlclient. so.18 =>/usr/lib64/mysql/libmysqlclient. so.18 (0x00007feb4ea24000)
Libz. so.1 =>/lib64/libz. so.1 (0x00007feb4e80d000)
Libcrypt. so.1 =>/lib64/libcrypt. so.1 (0x00007feb4e5d6000)
Libnsl. so.1 =>/lib64/libnsl. so.1 (0x00007feb4e3bd000)
Libssl. so.10 =>/lib64/libssl. so.10 (0x00007feb4e150000)
Libcrypto. so.10 =>/lib64/libcrypto. so.10 (0x00007feb4dd6b000)
LibQt5Sql. so.5 =>/home/eric/Qt5.5.0/5.5/gcc_64/lib/libQt5Sql. so.5 (0x00007feb4db2b000)
LibQt5Core. so.5 =>/home/eric/Qt5.5.0/5.5/gcc_64/lib/libQt5Core. so.5 (0x00007feb4d3e3000)
Libpthread. so.0 =>/lib64/libpthread. so.0 (0x00007feb4d1c7000)
Libstdc ++. so.6 =>/lib64/libstdc ++. so.6 (0x00007feb4cec0000)
Libm. so.6 =>/lib64/libm. so.6 (0x00007feb4cbbd000)
Libgcc_s.so.1 =>/lib64/libgcc_s.so.1 (0x00007feb4c9a7000)
Libc. so.6 =>/lib64/libc. so.6 (0x00007feb4c5e6000)
Libdl. so.2 =>/lib64/libdl. so.2 (0x00007feb4c3e1000)
Libfreebl3.so =>/lib64/libfreebl3.so (0x00007feb4c164000)
Libgssapi_krb5.so.2 =>/lib64/libgssapi_krb5.so.2 (0x00007feb4bf1a000)
Libkrb5.so. 3 =>/lib64/libkrb5.so. 3 (0x00007feb4bc39000)
Libcom_err.so.2 =>/lib64/libcom_err.so.2 (0x00007feb4ba35000)
Libk5crypto. so.3 =>/lib64/libk5crypto. so.3 (0x00007feb4b800000)
Libicui18n. so.54 =>/home/eric/Qt5.5.0/5.5/gcc_64/lib/libicui18n. so.54 (0x00007feb4b391000)
Libicuuc. so.54 =>/home/eric/Qt5.5.0/5.5/gcc_64/lib/libicuuc. so.54 (0x00007feb4afe3000)
Libicudata. so.54 =>/home/eric/Qt5.5.0/5.5/gcc_64/lib/libicudata. so.54 (0x00007feb495b9000)
Libgthread-2.0.so.0 =>/lib64/libgthread-2.0.so.0 (0x00007feb493b6000)
Librt. so.1 =>/lib64/librt. so.1 (0x00007feb491ae000)
Libglib-2.0.so.0 =>/lib64/libglib-2.0.so.0 (0x00007feb48e85000)
/Lib64/ld-linux-x86-64.so.2 (0x00007feb4f221000)
Libkrb5support. so.0 =>/lib64/libkrb5support. so.0 (0x00007feb48c76000)
Libkeyutils. so.1 =>/lib64/libkeyutils. so.1 (0x00007feb48a72000)
Libresolv. so.2 =>/lib64/libresolv. so.2 (0x00007feb48858000)
Libselinux. so.1 =>/lib64/libselinux. so.1 (0x00007feb48632000)
Libpcre. so.1 =>/lib64/libpcre. so.1 (0x00007feb483d1000)
Liblzma. so.5 =>/lib64/liblzma. so.5 (0x00007feb481ab000)

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