今天工作有些东西需要整理，现在整理一下。
注意：本文首次撰写于2018-11-26，最近修改时间为2018-11-26，请注意相关程序的可用性与安全性。
下载与安装
下载mysql社区版rpm软件包 (可到MySQL官方找到最新的下载地址)：
localhost:software # wget http://ftp.iij.ad.jp/pub/db/mysql/Downloads/MySQL-5.7/mysql-5.7.24-1.sles11.x86_64.rpm-bundle.tar
解压查看：
localhost:software # tar -xvf mysql-5.7.24-1.sles11.x86_64.rpm-bundle.tar
解压后有下述文件：
mysql-community-client-5.7.24-1.sles11.x86_64.rpm
mysql-community-common-5.7.24-1.sles11.x86_64.rpm
mysql-community-devel-5.7.24-1.sles11.x86_64.rpm
mysql-community-embedded-5.7.24-1.sles11.x86_64.rpm
mysql-community-embedded-devel-5.7.24-1.sles11.x86_64.rpm
mysql-community-libs-5.7.24-1.sles11.x86_64.rpm
mysql-community-server-5.7.24-1.sles11.x86_64.rpm
mysql-community-test-5.7.24-1.sles11.x86_64.rpm
用yast2先卸载已存在的MySQL的rpm包。之后再安装新版本MySQL。如果需要什么依赖，请先安装依赖。
经过上面的解压操作，我们得到了很多rpm文件。但是我们不需要这么多，我们只需要安装一下四个组件就可以了：
mysql-community-common-5.7.24-1.sles11.x86_64.rpm
mysql-community-libs-5.7.24-1.sles11.x86_64.rpm
mysql-community-client-5.7.24-1.sles11.x86_64.rpm
mysql-community-server-5.7.24-1.sles11.x86_64.rpm
因为具有依赖关系，所以我们需要按顺序执行。 用rpm -ivh文件名就能安装相应的组件。 在执行server的时候，需要依赖安装一些工具组件，已经在上文有说明了。安装命令如下：
localhost:software # rpm -ivh mysql-community-common-5.7.24-1.sles11.x86_64.rpm
localhost:software # rpm -ivh mysql-community-libs-5.7.24-1.sles11.x86_64.rpm
localhost:software # rpm -ivh mysql-community-client-5.7.24-1.sles11.x86_64.rpm
localhost:software # rpm -ivh mysql-community-server-5.7.24-1.sles11.x86_64.rpm
执行具体记录：
localhost:software # rpm -ivh mysql-community-common-5.7.24-1.sles11.x86_64.rpm
warning: mysql-community-common-5.7.24-1.sles11.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-common-5.7.24-1.e################################# [100%]
localhost:software # rpm -ivh mysql-community-libs-5.7.24-1.sles11.x86_64.rpm
warning: mysql-community-libs-5.7.24-1.sles11.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-libs-5.7.24-1.sles11################################# [100%]
localhost:software # rpm -ivh mysql-community-client-5.7.24-1.sles11.x86_64.rpm
warning: mysql-community-client-5.7.24-1.sles11.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-client-5.7.24-1.e################################# [100%]
localhost:software # rpm -ivh mysql-community-server-5.7.24-1.sles11.x86_64.rpm
warning: mysql-community-server-5.7.24-1.sles11.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-server-5.7.24-1.e################################# [100%]
之后就可以通过service命令进行mysql的管理了：
# 查看mysql是否启动
service mysql status
# 启动mysql
service mysql start
# 停止mysql
service mysql stop
# 重启mysql
service mysql restart
另外，可以新建mysql用户以便使用。
useradd mysql
这里注意，如果不执行启动会报错，具体报错为：
ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)
必须执行service mysql start才可以进行下一步。
设置密码
mysql安装并启动完成之后我们是没有设置密码的，但是mysql为我们设置了一个临时的密码，我们可以查看mysql的日志知道这个临时密码。
grep password /var/log/mysql/mysqld.log
执行过程
localhost:software # grep password /var/log/mysql/mysqld.log
2017-09-01T16:43:10.889769Z 1 [Note] A temporary password is generated for root@localhost: hcLMTxbOh2?w
这样我们得知临时密码是：hcLMTxbOh2?w。 然后我们用这个临时密码登录数据库。数据库的密码需要满足以下条件：大小写字母，数字和特殊符号
执行命令
# 登录mysql，之后需要输入密码
mysql -p
# 设置新密码
set password = password("ZNing_123456");
# 退出当前登录
quit;
# 或用如下命令退出
exit
执行过程
localhost ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.7.19 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> set password = password("ZNing_123456");
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> quit;
重新登录，这样我们就能用新的密码登录了。我们可以愉快的进行数据库操作了。
远程访问开启
连接数据库后访问mysql数据库：
mysql> use mysql; (此DB存放MySQL的各种配置信息)
Database changed
mysql> select host,user from user; (查看用户的权限情况)
+-------------+-------+
| host | user |
+-------------+-------+
| localhost | |
| localhost | root |
| localhost | |
| localhost | mysql |
+-------------+-------+
6 rows in set (0.02 sec)
由此可以看出，只能以localhost的主机方式访问。紧接着执行下面的命令：
mysql> grant all privileges on *.* to 'root'@'%' identified by 'password' with grant option;
#(%表示是所有的外部机器，如果指定某一台机，就将%改为相应的机器名；‘root’则是指要使用的用户名，里面的password需要自己修改成root的密码)
mysql> flush privileges; #(运行为句才生效，或者重启MySQL)
Query OK, 0 rows affected (0.03 sec)
mysql> select host,user from user; #(再次查看用户的权限情况)
+-------------+-------+
| host | user |
+-------------+-------+
| ％ | mysql |
| ％ | root |
| localhost | |
| localhost | root |
| localhost | |
| localhost | mysql |
+-------------+-------+
mysql>exit
现在再试试：从远程cmd那边看能不能登录，能登录的话，一般用代码也是可以连接的到的。另外需要注意的是用户权限表是在mysql数据库的db表，里面详细记录了哪些用户有权限对哪几个数据库有操作的权限，这个对多用户的管理比较重要。
但是在执行过程中，我的mysql报了个神奇的错误：
mysql> grant all privileges on *.* to 'root'@'%' identified by 'password' with grant option;
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
经查，此报错与MySQL5.6.6版本之后增加了密码强度验证插件validate_password有关，相关参数设置的较为严格。因此会报此问题。该问题其实与mysql的validate_password_policy的值有关。查看一下MySQL密码相关的几个全局参数：
mysql> select @@validate_password_policy;
+----------------------------+
| @@validate_password_policy |
+----------------------------+
| MEDIUM |
+----------------------------+
1 row in set (0.00 sec)
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name | Value |
+--------------------------------------+--------+
| validate_password_dictionary_file | |
| validate_password_length | 8 |
| validate_password_mixed_case_count | 1 |
| validate_password_number_count | 1 |
| validate_password_policy | MEDIUM |
| validate_password_special_char_count | 1 |
+--------------------------------------+--------+
6 rows in set (0.08 sec)
参数解释：
validate_password_dictionary_file是插件用于验证密码强度的字典文件路径。
validate_password_length是密码最小长度，参数默认为8，它有最小值的限制，最小值为：validate_password_number_count + validate_password_special_char_count + (2 * validate_password_mixed_case_count)
validate_password_mixed_case_count是密码至少要包含的小写字母个数和大写字母个数。
validate_password_number_count是密码至少要包含的数字个数。
validate_password_policy是密码强度检查等级，0/LOW、1/MEDIUM、2/STRONG。有以下取值：
| Policy | Tests Performed |
|---|---|
| 0 or LOW | Length |
| 1 or MEDIUM | Length; numeric, lowercase/uppercase, and special characters |
| 2 or STRONG | Length; numeric, lowercase/uppercase, and special characters; dictionary file |
| 默认是1，即MEDIUM，所以刚开始设置的密码必须符合长度，且必须含有数字，小写或大写字母，特殊字符。 |
validate_password_special_char_count密码至少要包含的特殊字符数。
由此，进行MySQL的权限放低设置：
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.05 sec)
mysql> set global validate_password_mixed_case_count=0;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_number_count=3;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_special_char_count=0;
Query OK, 0 rows affected (0.00 sec)
mysql> set global validate_password_length=3;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| validate_password_dictionary_file | |
| validate_password_length | 3 |
| validate_password_mixed_case_count | 0 |
| validate_password_number_count | 3 |
| validate_password_policy | LOW |
| validate_password_special_char_count | 0 |
+--------------------------------------+-------+
6 rows in set (0.00 sec)
注意：这种操作会对账户密码的安全性管理大大降低，请谨慎操作。
再次执行命令，即可通过：
mysql> grant all privileges on *.* to 'root'@'%' identified by 'password' with grant option;
Query OK, 0 rows affected (0.00 sec)
再用MySQL Workbench或者Navicat连接即可。
参考文献
- https://blog.csdn.net/fanshujuntuan/article/details/78077433
- http://blog.51cto.com/putian/1287959
- https://blog.csdn.net/maxsky/article/details/51171474
- http://wiki.jikexueyuan.com/project/git-tutorial/remote-repository.html
- http://www.luxinzhi.com/system/140.html
- https://overtrue.me/articles/2015/05/install-latest-git-on-centos.html
- https://blog.csdn.net/zsx157326/article/details/80059068
- https://blog.csdn.net/chenqiai0/article/details/83472410
- https://www.jianshu.com/p/3478e2a214a1