MySQL 5.7版本據說已經在了很大的性能提升以及做得更加安全了，想了解更多MySQL 5.7的新特性可以參考我轉載葉金榮老師的MySQL 5.7的新特性說明。這里我簡單演示一下MySQL 5.7的安裝已經一些新特性的使用，希望大家能一起進去，一起探討技術。
MySQL 5.7的官方下載地址：http://cdn.mysql.com//Downloads/MySQL-5.7/mysql-5.7.10-linux-glibc2.5-x86_64.tar.gz
下面簡單介紹一下安裝：
[root@MySQL soft]# tar xf mysql-5.7.10-linux-glibc2.5-x86_64.tar.gz -C /data/service/ [root@MySQL soft]# cd /data/service/ [root@MySQL service]# mv mysql-5.7.10-linux-glibc2.5-x86_64/ mysql-5.7.10
下面進行數據目錄的創建以及授權：
[root@MySQL service]# mkdir /data/{mysql3306,mysql3306log} -p [root@MySQL service]# groupadd mysql [root@MySQL service]# useradd -r -g mysql mysql [root@MySQL service]# chown -R mysql:mysql mysql-5.7.10/ [root@MySQL service]# chown -R mysql:mysql /data/mysql3306*
基本操作已經完成，下面進行初始化操作，在MySQL 5.7的初始化操作與MySQL 5.6有點不同了，下面在MySQL 5.7的版本用MySQL 5.6的初始化方式進行操作一下，讓大家看下會報什么錯：
[root@MySQL mysql-5.7.10]# ./bin/mysql_install_db --user=mysql --datadir=/data/mysql3306 2016-01-21 11:29:05 [WARNING] mysql_install_db is deprecated. Please consider switching to mysqld --initialize 2016-01-21 11:29:10 [ERROR] The bootstrap log isn't empty: 2016-01-21 11:29:10 [ERROR] 2016-01-21T03:29:05.633658Z 0 [Warning] --bootstrap is deprecated. Please consider using --initialize instead 2016-01-21T03:29:05.641584Z 0 [ERROR] Can't read from messagefile '/usr/share/mysql/english/errmsg.sys' [root@MySQL mysql-5.7.10]#
可以看到mysql_install_db is deprecated，說不贊同使用mysql_install_db，推薦使用的方法是：
Please consider switching to mysqld --initialize ，Please consider using --initialize instead
正確的初始方式如下：./bin/mysqld --initialize --user=mysql --basedir=/data/service/mysql-5.7.10/ --datadir=/data/mysql3306，如果datadir目錄有文件，則會報以下錯：
[root@MySQL mysql-5.7.10]# ./bin/mysqld --initialize --user=mysql --basedir=/data/service/mysql-5.7.10/ --datadir=/data/mysql3306 2016-01-21T05:43:56.355999Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 2016-01-21T05:43:56.357796Z 0 [ERROR] --initialize specified but the data directory has files in it. Aborting. 2016-01-21T05:43:56.357814Z 0 [ERROR] Aborting
所以要把data directory文件刪除掉再執行，如果刪除目錄下的文件還是報同樣的錯，可以試試把目錄刪除掉，再創建一個，然后授權：
[root@MySQL mysql-5.7.10]# ./bin/mysqld --initialize --user=mysql --basedir=/data/service/mysql-5.7.10/ --datadir=/data/mysql3306 2016-01-21T05:47:01.804937Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 2016-01-21T05:47:03.552899Z 0 [Warning] InnoDB: New log files created, LSN=45790 2016-01-21T05:47:03.816849Z 0 [Warning] InnoDB: Creating foreign key constraint system tables. 2016-01-21T05:47:03.883956Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 660686ae-c002-11e5-843e-00163e0217d7. 2016-01-21T05:47:03.886131Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened. 2016-01-21T05:47:03.887120Z 1 [Note] A temporary password is generated for root@localhost: )vyd3aXj8hhC
MySQL 5.7初始化完后會生成一個臨時的密碼，A temporary password is generated for root@localhost: )vyd3aXj8hhC 如果想初始化表空間，在后面加上 --innodb_data_file_path=ibdata1:1G:autoextend即可。
啟動MySQL 5.7，拷貝support-files/my-default.cnf ./
[root@MySQL mysql-5.7.10]# cp support-files/my-default.cnf ./my.cnf [root@MySQL mysql-5.7.10]# chown -R mysql:mysql my.cnf
編輯my.cnf加上基本選項：
[mysqld] # changes to the binary log between backups. log_bin # These are commonly set, remove the # and set as required. basedir = /data/service/mysql-5.7.10 datadir = /data/mysql3306 port = 3306 server_id = 100 socket = /tmp/mysqld.sock
編輯啟動腳本：
[root@MySQL mysql-5.7.10]# cat start_mysql.sh #!/bin/bash nohup /data/service/mysql-5.7.10/bin/mysqld_safe --defaults-file=/data/service/mysql-5.7.10/my.cnf > /data/service/mysql-5.7.10/start_stop.log 2>&1 &
運行腳本啟動 sh start_mysql.sh 。
登錄MySQL 5.7，先添加MySQL 5.7的bin路徑：
[root@MySQL mysql-5.7.10]# cat /etc/profile.d/mysql.sh export PATH=/data/service/mysql-5.7.10/bin:$PATH [root@MySQL mysql-5.7.10]# source /etc/profile.d/mysql.sh
登錄時輸入的密碼是剛剛初始化完的密碼：
[root@MySQL mysql-5.7.10]# mysql -uroot -p')vyd3aXj8hhC' -S /tmp/mysqld.sock mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.7.10-log Copyright (c) 2000, 2015, 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>
第一次登錄，是必須要修改密碼才能查看show databases;
mysql> show databases; ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement. mysql>
從上面的信息可以看到，叫我們使用ALTER USER進行修改，下面我們修改一下密碼，有關更多MySQL 5.7的用戶密碼設置可以參考：https://dev.mysql.com/doc/refman/5.7/en/password-expiration-policy.html
mysql> ALTER USER USER() IDENTIFIED BY '123456'; Query OK, 0 rows affected (0.01 sec) mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec) mysql>
MySQL 5.7的mysql.user表已經沒有password這一列了，所以查詢用戶和密碼的方式如下：
mysql> select user,host,authentication_string from mysql.user; +-----------+-----------+-------------------------------------------+ | user | host | authentication_string | +-----------+-----------+-------------------------------------------+ | root | localhost | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | | mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE | +-----------+-----------+-------------------------------------------+ 2 rows in set (0.00 sec) mysql> select password('123456'); +-------------------------------------------+ | password('123456') | +-------------------------------------------+ | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | +-------------------------------------------+ 1 row in set, 1 warning (0.00 sec)
MySQL 5.7支持為表增加計算列
什么叫計算列呢，簡單來說就是某一列的值是通過別的列計算得來，例如a列值為1，b列值為2，c列不需要操作手動插入，定義為a + b的結果為c的值，那么c就是計算列，是通過別的列計算得來，下面我們進行例子說明：
在MySQL 5.7之前的版本中，要實現這樣的效果要利用觸發器來完成，以下是以前的實現過程：
mysql> show create table tb1\G *************************** 1. row *************************** Table: tb1 Create Table: CREATE TABLE `tb1` ( `id` int(11) NOT NULL AUTO_INCREMENT, `c1` int(11) DEFAULT NULL, `c2` int(11) DEFAULT NULL, `c3` int(11) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin 1 row in set (0.01 sec) mysql>
創建一個插入的觸發器：
mysql> create trigger insert_tb1 before insert on tb1 for each row set new.c3=new.c1+new.c2; Query OK, 0 rows affected (0.01 sec)
我們插入數據：
mysql> insert into tb1(c1,c2) values (1,2); Query OK, 1 row affected (0.00 sec) mysql> select * from tb1; +----+------+------+------+ | id | c1 | c2 | c3 | +----+------+------+------+ | 1 | 1 | 2 | 3 | +----+------+------+------+ 1 row in set (0.00 sec) mysql>
但如果我們更新了c1或者c2的值，c3是不會變動的，所以我們要加一個update的觸發器：
mysql> select * from tb1; +----+------+------+------+ | id | c1 | c2 | c3 | +----+------+------+------+ | 1 | 1 | 2 | 3 | +----+------+------+------+ 1 row in set (0.00 sec) mysql> create trigger update_tb1 before update on tb1 for each row set new.c3=new.c1+new.c2; Query OK, 0 rows affected (0.01 sec) mysql> update tb1 set c1 = 3; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from tb1; +----+------+------+------+ | id | c1 | c2 | c3 | +----+------+------+------+ | 1 | 3 | 2 | 5 | +----+------+------+------+ 1 row in set (0.00 sec) mysql>
可以看到，如果想實現計算列，那么就要借助觸發器或者視圖來實現，但在生產環境中，是不太建議使用觸發器或者視圖的。下面用MySQL 5.7來實現就變得很簡單了。
MySQL 5.7計算列的實現：
在CREAE TABLE和ALTER TABLE 中都支持增加計算列的方式：
col_name data_type [GENERATED ALWAYS] AS (expression) [VIRTUAL | STORED] [UNIQUE [KEY]] [COMMENT comment] [NOT NULL | NULL] [[PRIMARY] KEY]
下面我們創建測試表tb2:
mysql> show create table tb2\G *************************** 1. row *************************** Table: tb2 Create Table: CREATE TABLE `tb2` ( `id` int(11) NOT NULL AUTO_INCREMENT, `c1` int(11) DEFAULT NULL, `c2` int(11) DEFAULT NULL, `c3` int(11) GENERATED ALWAYS AS ((`c1` + `c2`)) VIRTUAL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 1 row in set (0.00 sec) mysql>
插入數據看效果：
mysql> select * from tb2; Empty set (0.00 sec) mysql> insert into tb2(c1,c2) values (1,2); Query OK, 1 row affected (0.00 sec) mysql> select * from tb2; +----+------+------+------+ | id | c1 | c2 | c3 | +----+------+------+------+ | 1 | 1 | 2 | 3 | +----+------+------+------+ 1 row in set (0.00 sec) mysql>
更新數據看效果：
mysql> update tb2 set c1=10; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from tb2; +----+------+------+------+ | id | c1 | c2 | c3 | +----+------+------+------+ | 1 | 10 | 2 | 12 | +----+------+------+------+ 1 row in set (0.00 sec) mysql>
可以看到相當的方便，MySQL 5.7的很多新特性都給我們帶來了便利和驚喜^.^
總結：
一、MySQL 5.7初始方法相比之前的版本都有所不同，做的相對更為安全了，以前版本初始化完root密碼是空的，MySQL 5.7則有一個臨時密碼。
二、MySQL 5.7在CREAE TABLE和ALTER TABLE 中都支持增加計算列的方式了，所有可以少用觸發器和視圖來實現計算列了。
三、MySQL 5.7無論在性能還是安全性方面都得到了很大的提升，希望小伙伴們一起好好學習MySQL 5.7的一些新特性。
參考資料：
http://dev.mysql.com/doc/refman/5.7/en/binary-installation.html
https://dev.mysql.com/doc/refman/5.7/en/password-expiration-policy.html
http://dev.mysql.com/doc/refman/5.7/en/create-table.html
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作者：陸炫志 出處：xuanzhi的博客 http://www.cnblogs.com/xuanzhi201111 您的支持是對博主最大的鼓勵，感謝您的認真閱讀。本文版權歸作者所有，歡迎轉載，但請保留該聲明。
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