8.22 13.1-13.3
13.1 設置更改root密碼
?
Mysql的root用戶為mysql的超級管理員用戶，類似linux下的root
也可以創建普通用戶連接mysql
默認mysql的root密碼為空
?
操作：
檢查mysql服務是否啟動
[root@hyc-01-01 ~]# ps aux|grep mysql
root?????? 922? 0.0? 0.1 115432? 1476 ???????? S??? 8月21?? 0:00 /bin/sh /usr/local/mysql/binmysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/hyc-01-01.pid
mysql???? 1155? 0.0 44.7 1302728 451120 ?????? Sl?? 8月21?? 1:25 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=hyc-01-01.err --pid-file=/data/mysql/hyc-01-01.pid --socket=/tmp/mysql.sock
root????? 2607? 0.0? 0.0 112724?? 980 pts/1??? S+?? 20:31?? 0:00 grep --color=auto mysql
若未啟動則需要啟動：
[root@hyc-01-01 ~]# /etc/init.d/mysqld start
Mysql相關命令在/usr/local/mysql/bin路徑下，但該路徑不在環境變量PATH中
[root@hyc-01-01 ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
所以執行mysql相關命令時會報錯提示命令未找到
為了能正常執行mysql的命令，需要將該路徑加入環境變量PATH
1
[root@hyc-01-01 ~]# export PATH=$PATH:/usr/local/mysql/bin/
[root@hyc-01-01 ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/usr/local/mysql/bin/ 臨時生效（系統重啟后失效）
2 永久生效
[root@hyc-01-01 ~]# vim /etc/profile
…
??? fi
done
?
unset i
unset -f pathmunge
export PATH=$PATH:/usr/local/mysql/bin/
[root@hyc-01-01 ~]# source /etc/profile
執行profile文件（改寫/etc/profile后若不重新執行則改寫的內容不生效）
此時mysql相關命令執行正常
[root@hyc-01-01 ~]# mysql -uroot –p 指定使用root登錄mysql，-p參數用于指定密碼
Enter password:
…
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
?
mysql> 此時已經登入mysql，用戶可以在這里操作mysql
mysql> quit quit登出mysql
Bye
首次設置root用戶密碼：
[root@hyc-01-01 ~]# mysqladmin -uroot password 'hyclinux.1'
Warning: Using a password on the command line interface can be insecure.
這里系統認為密碼明文顯示不安全，所以會出現提示，不是錯誤，可以不管
?
再次使用root用戶登入mysql：
[root@hyc-01-01 ~]# mysql -uroot
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
未提供密碼登入操作被拒絕
?
再次修改root用戶密碼：
[root@hyc-01-01 ~]# mysqladmin -uroot -p'hyclinux.1' password 'hyc940421'
Warning: Using a password on the command line interface can be insecure.
注意：
需要使用-p參數輸入原來的密碼
-p參數后緊跟密碼，沒有空格
通常使用單引號使所有特殊字符去義
?
在不知道root密碼的情況下修改root密碼：
修改/etc/my.cnf配置文件：
[root@hyc-01-01 ~]# vim /etc/my.cnf
? 1 [mysqld]
? 2 skip-grant 忽略授權，即在用戶登錄mysql時不需要密碼
? 3 federated
? 4 datadir=/data/mysql
? 5 socket=/tmp/mysql.sock
…
重啟服務：
[root@hyc-01-01 ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
無需密碼直接登錄：
[root@hyc-01-01 ~]# mysql -uroot
Welcome to the MySQL monitor.? Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.39 MySQL Community Server (GPL)
?
Copyright (c) 2000, 2018, 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>
更改root密碼：
修改mysql中的mysql庫中的user表，這里記錄了用戶名、密碼、權限等信息
mysql> use mysql； 切換到mysql庫
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
?
Database changed
mysql> select * from user; 查看mysql庫中的信息
mysql> select password from user;
+-------------------------------------------+
| password??????????????????????????? ??????|
+-------------------------------------------+
| *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
|???????????????? ??????????????????????????|
|?????????????????????????????????????????? |
+-------------------------------------------+
6 rows in set (0.00 sec)
在user表中密碼信息是加密的字符串，這些加密的字符串由password函數生成，所以修改密碼時也需要password函數對密碼進行加密
mysql> update user set password=password('123456') where user='root';
設置root密碼為123456并使用password函數加密
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4? Changed: 4? Warnings: 0 第4行發生改變
?
刪除/etc/my.cnf中的skip-grant后重啟mysql服務測試：
[root@hyc-01-01 ~]# mysql -uroot -p
Enter password:? 這里輸入123456
…
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
?
mysql>
?
13.2 連接mysql
?
連接本機
[root@hyc-01-01 ~]# mysql -uroot -p
連接遠程
[root@hyc-01-01 ~]# mysql -uroot -p123456 -h127.0.0.1 -P3306
Socket連接（僅本機連接）
[root@hyc-01-01 ~]# mysql -uroot -p123456 -S/tmp/mysql.sock
連接后執行操作
[root@hyc-01-01 ~]# mysql -uroot -p123456 -e "show databases"
Warning: Using a password on the command line interface can be insecure.
+--------------------+
| Database?????????? |
+--------------------+
| information_schema |
| mysql????????????? |
| performance_schema |
| test?????????????? |
+--------------------+
?
13.3 mysql常用命令
?
Mysql的中的所有命令需要；作為命令的結尾
?
查看包含了哪些數據庫
mysql> show databases;
+--------------------+
| Database?????????? |
+--------------------+
| information_schema |
| mysql????????????? |
| performance_schema |
| test?????????????? |
+--------------------+
4 rows in set (0.00 sec)
?
進入庫
mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
?
Database changed
?
查看數據庫中的表
mysql> show tables;
+---------------------------+
| Tables_in_mysql?????????? |
+---------------------------+
| columns_priv????????????? |
| db??????????????????????? |
| event???????????????????? |
| func????????????????????? |
| general_log?????????????? |
| help_category???????????? |
| help_keyword????????????? |
| help_relation???????????? |
| help_topic??????????????? |
| innodb_index_stats??????? |
| innodb_table_stats??????? |
| ndb_binlog_index????????? |
| plugin??????????????????? |
| proc????????????????????? |
| procs_priv??????????????? |
| proxies_priv????????????? |
| servers?????????????????? |
| slave_master_info???????? |
| slave_relay_log_info????? |
| slave_worker_info???????? |
| slow_log????????????????? |
| tables_priv?????????????? |
| time_zone???????????????? |
| time_zone_leap_second???? |
| time_zone_name??????????? |
| time_zone_transition????? |
| time_zone_transition_type |
| user????????????????????? |
+---------------------------+
28 rows in set (0.00 sec)
?
查看user表中包含的字段
mysql> desc user;
?
查看mysql數據庫中的user表是如何創建的
mysql> show create table user\G;
*************************** 1. row ***************************
?????? Table: user
Create Table: CREATE TABLE `user` (
? `Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '',
? `User` char(16) COLLATE utf8_bin NOT NULL DEFAULT '',
? `Password` char(41) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT '',
? `Select_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Insert_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Update_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Delete_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Create_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Drop_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Reload_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Shutdown_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Process_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `File_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Grant_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `References_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Index_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Alter_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Show_db_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Super_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Create_tmp_table_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Lock_tables_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Execute_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Repl_slave_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Repl_client_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Create_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Show_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Create_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Alter_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Create_user_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Event_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Trigger_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `Create_tablespace_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? `ssl_type` enum('','ANY','X509','SPECIFIED') CHARACTER SET utf8 NOT NULL DEFAULT '',
? `ssl_cipher` blob NOT NULL,
? `x509_issuer` blob NOT NULL,
? `x509_subject` blob NOT NULL,
? `max_questions` int(11) unsigned NOT NULL DEFAULT '0',
? `max_updates` int(11) unsigned NOT NULL DEFAULT '0',
? `max_connections` int(11) unsigned NOT NULL DEFAULT '0',
? `max_user_connections` int(11) unsigned NOT NULL DEFAULT '0',
? `plugin` char(64) COLLATE utf8_bin DEFAULT 'mysql_native_password',
? `authentication_string` text COLLATE utf8_bin,
? `password_expired` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',
? PRIMARY KEY (`Host`,`User`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Users and global privileges'
1 row in set (0.00 sec)
?
ERROR:
No query specified
顯示的內容包括表的名稱、字段、每個字段的格式及其他參數，還有表的引擎、字符集和創建表使用的語句
如果不加/G顯示的內容會比較混亂
mysql> select * from user;
…
| Host????? | User | Password? ????????????????????????????????| Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | Show_db_priv | Super_priv | Create_tmp_table_priv | Lock_tables_priv | Execute_priv | Repl_slave_priv | Repl_client_priv | Create_view_priv | Show_view_priv | Create_routine_priv | Alter_routine_priv | Create_user_priv | Event_priv | Trigger_priv | Create_tablespace_priv | ssl_type | ssl_cipher | x509_issuer | x509_subject | max_questions | max_updates | max_connections | max_user_connections | plugin??????????????? | authentication_string | password_expired |
…
| localhost | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | Y?????????? | Y?????????? | Y?????????? | Y?????? ????| Y?????????? | Y???????? | Y?????????? | Y???????????? | Y??????????? | Y???????? | Y????????? | Y?????????????? | Y????????? | Y????????? | Y??????????? | Y????????? | Y???????????????????? | Y??????????????? | Y??????????? | Y?????????????? | Y???? ???????????| Y??????????????? | Y????????????? | Y?????????????????? | Y????????????????? | Y??????????????? | Y????????? | Y??????????? | Y????????????????????? |????????? |??????????? |???????????? |????????????? |???????????? 0 |?????????? 0 |????????? ?????0 |??????????????????? 0 | mysql_native_password |?????????????????????? | N??????????????? |
| hyc-01-01 | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | Y?????????? | Y?????????? | Y?????????? | Y?????????? | Y?????????? | Y???????? | Y???????? ??| Y???????????? | Y??????????? | Y???????? | Y????????? | Y?????????????? | Y????????? | Y????????? | Y??????????? | Y????????? | Y???????????????????? | Y??????????????? | Y??????????? | Y?????????????? | Y??????????????? | Y??????????????? | Y???????? ?????| Y?????????????????? | Y????????????????? | Y??????????????? | Y????????? | Y??????????? | Y????????????????????? |????????? |??????????? |???????????? |????????????? |???????????? 0 |?????????? 0 |?????????????? 0 |??????????????????? 0 | mysql_native_password |?????????????????????? | N??????????????? |
| 127.0.0.1 | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | Y?????????? | Y?????????? | Y?????????? | Y?????????? | Y?????????? | Y???????? | Y?????????? | Y???????????? | Y??????????? | Y????? ???| Y????????? | Y?????????????? | Y????????? | Y????????? | Y??????????? | Y????????? | Y???????????????????? | Y??????????????? | Y??????????? | Y?????????????? | Y??????????????? | Y??????????????? | Y????????????? | Y?????????????????? | Y??????????? ??????| Y??????????????? | Y????????? | Y??????????? | Y????????????????????? |????????? |??????????? |???????????? |????????????? |???????????? 0 |?????????? 0 |?????????????? 0 |??????????????????? 0 | mysql_native_password |?????????????????????? | N?? ?????????????|
| ::1?????? | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | Y?????????? | Y?????????? | Y?????????? | Y?????????? | Y?????????? | Y???????? | Y?????????? | Y???????????? | Y??????????? | Y???????? | Y????????? | Y?????????????? | Y????????? | Y?????? ???| Y??????????? | Y????????? | Y???????????????????? | Y??????????????? | Y??????????? | Y?????????????? | Y??????????????? | Y??????????????? | Y????????????? | Y?????????????????? | Y????????????????? | Y??????????????? | Y????????? | Y??????????? | Y ?????????????????????|????????? |??????????? |???????????? |????????????? |???????????? 0 |?????????? 0 |?????????????? 0 |??????????????????? 0 | mysql_native_password |?????????????????????? | N??????????????? |
| localhost |????? |????????????????????? ?????????????????????| N?????????? | N??????????
?????????? 0 |?????????????? 0 |??????????????????? 0 | mysql_native_password | NULL????????????????? | N??????????????? |
…
6 rows in set (0.00 sec)
…
mysql> select * from user\G;
*************************** 1. row ***************************
????????????????? Host: localhost
??????????????? ??User: root
????????????? Password: *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9
?????????? Select_priv: Y
?????????? Insert_priv: Y
?????????? Update_priv: Y
?????????? Delete_priv: Y
?????????? Create_priv: Y
???????????? Drop_priv: Y
?????????? Reload_priv: Y
???????? Shutdown_priv: Y
????????? Process_priv: Y
???????????? File_priv: Y
??????????? Grant_priv: Y
?????? References_priv: Y
??????????? Index_priv: Y
??????????? Alter_priv: Y
????????? Show_db_priv: Y
??????????? Super_priv: Y
?Create_tmp_table_priv: Y
????? Lock_tables_priv: Y
????????? Execute_priv: Y
…
?authentication_string:
????? password_expired: N
…
*************************** 3. row ***************************
????????????????? Host: 127.0.0.1
????????????????? User: root
?????? ???????Password: *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9
?????????? Select_priv: Y
?????????? Insert_priv: Y
?????????? Update_priv: Y
?????????? Delete_priv: Y
?????????? Create_priv: Y
???????????? Drop_priv: Y
?????????? Reload_priv: Y
???????? Shutdown_priv: Y
????????? Process_priv: Y
???????????? File_priv: Y
??????????? Grant_priv: Y
…
?authentication_string:
????? password_expired: N
*************************** 4. row ***************************
????????????????? Host: ::1
????????????????? User: root
????????????? Password: *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9
?…
?????????? max_updates: 0
?????? max_connections: 0
? max_user_connections: 0
??????????????? plugin: mysql_native_password
?authentication_string:
????? password_expired: N
*************************** 5. row ***************************
????????????????? Host: localhost
????????????????? User:
????????????? Password:
…
???????????? File_priv: N
??????? ????Grant_priv: N
?????? References_priv: N
??????????? Index_priv: N
??????????? Alter_priv: N
????????? Show_db_priv: N
??????????? Super_priv: N
?Create_tmp_table_priv: N
????? Lock_tables_priv: N
????????? Execute_priv: N
…
?????????? max_updates: 0
?????? max_connections: 0
? max_user_connections: 0
??????????????? plugin: mysql_native_password
?authentication_string: NULL
????? password_expired: N
*************************** 6. row ***************************
????????????????? Host: hyc-01-01
????????????????? User:
????????????? Password:
?????????? Select_priv: N
?????????? Insert_priv: N
?????????? Update_priv: N
?????????? Delete_priv: N
?????????? Create_priv: N
…
????? Create_user_priv: N
??????????? Event_priv: N
????????? Trigger_priv: N
Create_tablespace_priv: N
????????????? ssl_type:
??????????? ssl_cipher:
?????????? x509_issuer:
????????? x509_subject:
???????? max_questions: 0
?????????? max_updates: 0
?????? max_connections: 0
? max_user_connections: 0
??????????????? plugin: mysql_native_password
?authentication_string: NULL
????? password_expired: N
6 rows in set (0.00 sec)
?
ERROR:
No query specified
?
查看當前用戶：
mysql> select user();
+----------------+
| user()???????? |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)
當前用戶為root，主機名為localhost（即本地）
登出后重新登錄：
通過127.0.0.1登錄，默認端口3306
[root@hyc-01-01 ~]# mysql -uroot -p123456 -h127.0.0.1
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 10
Server version: 5.6.39 MySQL Community Server (GPL)
?
Copyright (c) 2000, 2018, 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> select user();
+----------------+
| user()???????? |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)
登錄用戶為root，主機名localhost
?
[root@hyc-01-01 ~]# mysql -uroot -p123456 -h192.168.31.129
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 11
Server version: 5.6.39 MySQL Community Server (GPL)
?
Copyright (c) 2000, 2018, 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> select user();
+----------------+
| user()???????? |
+----------------+
| root@hyc-01-01 |
+----------------+
1 row in set (0.00 sec)
登錄用戶為root，主機名hyc-01-01
這里ip地址192.168.31.129被反解析到主機名hyc-01-01
?
Mysql中也可以記錄命令歷史，使用上下方向鍵可以查看歷史命令（類似linux）
Mysql歷史命令記錄位置：
[root@hyc-01-01 ~]# ls -a|grep mysql_history
.mysql_history
[root@hyc-01-01 ~]# pwd
/root
?
Mysql也支持ctrl+L清屏
?
查看當前使用的數據庫：
mysql> select database();
+------------+
| database() |
+------------+
| NULL?????? |
+------------+
1 row in set (0.00 sec)
?
mysql> use mysql 使用use mysql時可以不加；
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
?
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| mysql????? |
+------------+
1 row in set (0.00 sec)
?
創建庫：
mysql> show databases;
+--------------------+
| Database?????????? |
+--------------------+
| information_schema |
| mysql????????????? |
| performance_schema |
| test?????????????? |
+--------------------+
4 rows in set (0.00 sec)
?
mysql> create database test1; 創建庫test1
Query OK, 1 row affected (0.00 sec)
?
mysql> show databases;
+--------------------+
| Database?????????? |
+--------------------+
| information_schema |
| mysql????????????? |
| performance_schema |
| test?????????????? |
| test1????????????? |
+--------------------+
5 rows in set (0.00 sec)
創建表：
mysql> use test1
Database changed
mysql> create table test1(`id` int(4), `name` char(40));
Query OK, 0 rows affected (0.04 sec)
在數據庫test1下創建表test1，表的字段包括id（數字形式，最長為4）和name（字符串形式，最長為40）
mysql> show create table test1\G;
*************************** 1. row ***************************
?????? Table: test1
Create Table: CREATE TABLE `test1` (
? `id` int(4) DEFAULT NULL,
? `name` char(40) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.00 sec)
?
ERROR:
No query specified
使用了默認引擎InnoDB，默認字符集latin1
mysql> #create table test1(`id` int(4),`name` char(40)) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CHARSET指定字符集為utf-8
ENGINE指定數據庫引擎為InnoDB
?
刪除表：
mysql> drop table test1;
Query OK, 0 rows affected (0.03 sec)
?
重新創建表test1：
mysql> create table test1(`id` int(4),`name` char(40)) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.03 sec)
?
mysql>? show create table test1\G;
*************************** 1. row ***************************
?????? Table: test1
Create Table: CREATE TABLE `test1` (
? `id` int(4) DEFAULT NULL,
? `name` char(40) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
?
ERROR:
No query specified
此時表使用的字符集為utf8
?
查看當前數據庫版本：
mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.39??? |
+-----------+
1 row in set (0.00 sec)
?
查看數據庫的狀態：
mysql> show status;
?
查看各種參數：
mysql> show variables;
這些參數均可以在my.cnf中定義
指定查看某個或某些參數：
mysql> show variables like 'max_connect%'; 查看匹配max_connect字段的參數（使用%表示通配）
+--------------------+-------+
| Variable_name????? | Value |
+--------------------+-------+
| max_connect_errors | 100?? |
| max_connections??? | 151?? |
+--------------------+-------+
2 rows in set (0.00 sec)
?
不加%則表示嚴格匹配
mysql> show variables like 'slow%';
+---------------------+--------------------------------+
| Variable_name?????? | Value????????????????????????? |
+---------------------+--------------------------------+
| slow_launch_time??? | 2????????????????????????????? |
| slow_query_log????? | OFF??????????????????????????? |
| slow_query_log_file | /data/mysql/hyc-01-01-slow.log |
+---------------------+--------------------------------+
3 rows in set (0.00 sec)
?
mysql> show variables like 'slow';
Empty set (0.00 sec)
?
修改參數：
1 可以修改配置文件 重啟生效，永久有效
[root@hyc-01-01 hyc]# vim /etc/my.cnf
2 命令行修改，使新的值在內存中生效 重啟失效
mysql> set global max_connect_errors=1000; 原來100
Query OK, 0 rows affected (0.00 sec)
?
查看隊列：
類似linux系統下用ps aux查看
mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host????? | db?? | Command | Time | State | Info???????????? |
+----+------+-----------+------+---------+------+-------+------------------+
| 12 | root | localhost | NULL | Sleep?? | 3002 |?????? | NULL???????????? |
| 13 | root | localhost | NULL | Sleep?? | 2991 |?????? | NULL???????????? |
| 20 | root | localhost | NULL | Query?? |??? 0 | init? | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
3 rows in set (0.00 sec)
使用show processlist顯示的最后一列（info）可能不完整，使用show full processlist會顯示完整
mysql> show full processlist;
+----+------+-----------+------+---------+------+-------+-----------------------+
| Id | User | Host????? | db?? | Command | Time | State | Info????????????????? |
+----+------+-----------+------+---------+------+-------+-----------------------+
| 12 | root | localhost | NULL | Sleep?? | 3013 |?????? | NULL????????????????? |
| 13 | root | localhost | NULL | Sleep?? | 3002 |?????? | NULL????????????????? |
| 20 | root | localhost | NULL | Query?? |??? 0 | init? | show full processlist |
+----+------+-----------+------+---------+------+-------+-----------------------+
3 rows in set (0.00 sec)
轉載于:https://blog.51cto.com/12216458/2163143
總結
以上是生活随笔為你收集整理的8.22 13.1-13.3的全部內容，希望文章能夠幫你解決所遇到的問題。
- 上一篇： 前端每日实战：114# 视频演示如何用纯
- 下一篇： thymeleaf 使用th:oncli