設置mysql用戶密碼、遠程鏈接數據庫、經常使用命令

第13章 MySQL經常使用操做

MySQL版本 5.6.35mysql

13.1 設置、更改root用戶密碼

首次直接使用mysql會提示‘該命令不存在’,緣由是尚未將該命令加入環境變量,若是要使用該命令,須要使用其絕對路徑:/usr/local/mysql/bin/mysql,爲了方便,先將其加入系統環境變量:sql

[root@1 ~]# exprt PATH=$PATH:/usr/local/mysql/bin/

至此,mysql命令路徑暫時加入環境變量,系統重啓後該變量會失效,若要永久生效,須要將其加入環境變量配置文件:shell

[root@1 ~]# vim /etc/profile
……
export PATH=$PATH:/usr/local/mysql/bin/

刷新配置文件(不然不生效):
[root@1 ~]# source /etc/profile

設置 & 更改密碼

首次登錄mysql,root用戶沒有密碼,直接登陸:數據庫

[root@1 ~]# mysql -uroot
#-u:=user,指定用戶名
Welcome to the MySQL monitor.  Commands end with ; or \g.
……
mysql> quit
#退出

說明: 登陸mysql以後能夠進行與mysql相關的一些操做,可是設置mysql用戶的密碼須要執行如下操做!vim

設置密碼

[root@1 ~]# mysqladmin -uroot password '123456'  

再次登陸:
[root@1 ~]# mysql -uroot
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

說明: 設置密碼後直接登陸會報錯(ERROR),須要輸入密碼登陸。安全

[root@1 ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.
mysql>

注: -p=passwd,使用密碼登陸,在此能夠將密碼直接輸入在命令行(跟在-p後面,不加空格:-p'123456'<此處單引號能夠不加,可是當密碼中有特殊符號時必須加,因此在命令行輸入密碼時養成習慣:加單引號>),也能夠不在命令行輸入,只跟-p選項,而後根據提示信息:「Enter password」,輸入密碼進行登陸(此方法不會暴露用戶密碼,安全)。dom

更改密碼

  • 當知道用戶密碼時,進行密碼更改:
[root@1 ~]# mysqladmin -uroot -p'123456' password '1234567'

[root@1 ~]# mysql -uroot -p'1234567'
Welcome to the MySQL monitor.
mysql>

更改爲功!socket

  • 忘記密碼時,進行密碼更改:
先編輯mysql配置文件:
[root@1 ~]# vim /etc/my.cnf
[mysqld]
skip-grant
#忽略受權!
datadir=/data/mysql
socket=/tmp/mysql.sock

重啓mysql服務:
[root@1 ~]# /etc/init.d/mysqld restart
Shutting down MySQL... SUCCESS! 
Starting MySQL..................... SUCCESS!

說明: 完成該操做以後就能夠任意登陸mysql了(無需密碼),因此此時mysql安全性不好,平時配置文件中必定不要添加該參數!!!ui

[root@1 ~]# mysql -uroot
Welcome to the MySQL monitor.  
mysql> use mysql;
#切換mysql庫
Database changed
mysql> select * from user\G;
#查看用戶的表信息,該表中存放的是用戶相關信息(密碼、受權…)
#G選項的做用是使輸出信息有序顯示,不加該選項,顯示內容會很亂  
mysql> select password from user;
#查看用戶密碼,顯示結果Wie加密字符串!  
mysql> update user set password=password('123456') where user='root';
Query OK, 4 rows affected (0.11 sec)
Rows matched: 4  Changed: 4  Warnings: 0
#將密碼更改成‘123456’
mysql> quit
Bye

密碼更改爲功!this

恢復配置文件:
[root@1 ~]# vim /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/tmp/mysql.sock

重啓mysql服務:
[root@1 ~]# /etc/init.d/mysqld restart 
Shutting down MySQL.. SUCCESS! 
Starting MySQL........... SUCCESS! 

登陸:
[root@1 ~]# mysql -uroot -p'123456'
Welcome to the MySQL monitor.
mysql> quit
Bye

Finished!
步驟: vim /etc/my.cnf-->添加skip-grant-->mysql restart-->登陸-->use mysql-->update user set password=...-->vim /etc/my.cnf-->刪除skip-grant-->mysql restart。

13.2 鏈接mysql(本地、遠程)

遠程鏈接:使用IP/port鏈接

[root@1 ~]# mysql -uroot -p123456 -h127.0.0.1 -P3306
Welcome to the MySQL monitor.
mysql> quit
Bye

注: -h:=host,指定IP;-P:=port,指定端口。

本地鏈接:使用socket鏈接

[root@1 ~]# mysql -uroot -p123456 -S/tmp/mysql.sock
Welcome to the MySQL monitor.
mysql> quit
Bye

注: -S:=socket,指定socket。此方法只適用於本地鏈接,等同於「mysql -uroot -p123456」。

顯示全部數據庫

[root@1 ~]# mysql -uroot -p'123456' -e "show databases"
Warning: Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+

注: 該方法使用於shell腳本中。

13.3 MySQL經常使用命令

查看庫信息:

•查詢庫 show databases;

• 切換庫 use mysql;

• 查看庫裏的表 show tables;

• 查看錶裏的字段 desc tb_name;

• 查看建表語句 show create table tb_name\G;

• 查看當前用戶 select user();

• 查看當前使用的數據庫 select databsase();

 

注: 以上命令均須要在mysql下執行;在mysql中每行命令末尾加上分號,表示該行命令執行結束。 tb_name即table name()表名。

示例:

[root@1 mysql]# mysql -uroot -p'123456'
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 5
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, 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> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.00 sec)

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
mysql> show tables;
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| columns_priv              |
| db                        |
| event                     |
| func                      |
| time_zone                 |
| time_zone_leap_second     |
+---------------------------+
28 rows in set (0.00 sec)

mysql> desc time_zone;
+------------------+------------------+------+-----+---------+----------------+
| Field            | Type             | Null | Key | Default | Extra          |
+------------------+------------------+------+-----+---------+----------------+
| Time_zone_id     | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| Use_leap_seconds | enum('Y','N')    | NO   |     | N       |                |
+------------------+------------------+------+-----+---------+----------------+
2 rows in set (0.11 sec)

mysql> show create table time_zone\G;
#G=grep篩選文字內容,規律顯示出來
*************************** 1. row ***************************
       Table: time_zone
Create Table: CREATE TABLE `time_zone` (
  `Time_zone_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `Use_leap_seconds` enum('Y','N') NOT NULL DEFAULT 'N',
  PRIMARY KEY (`Time_zone_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Time zones'
1 row in set (0.03 sec)

ERROR: 
No query specified

mysql> select user();
+----------------+
| user()         |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.07 sec)

mysql> select database();
+------------+
| database() |
+------------+
| mysql      |
+------------+
1 row in set (0.00 sec)

mysql> select * from user\G;
建立庫:
mysql> create database db1;
Query OK, 1 row affected (0.02 sec)

建立表:
mysql> use db1;  
#先切換到指定庫下
Database changed
mysql> create table t1(`id` int(4),`name` char(40));
#括號中是定義字段及字段格式,使用反引號引發來
Query OK, 0 rows affected (1.51 sec)

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.35    |
+-----------+
1 row in set (0.06 sec)

mysql> show status;
+-----------------------------------------------+-------------+
| Variable_name                                 | Value       |
+-----------------------------------------------+-------------+
| Aborted_clients                               | 0           |
| Aborted_connects                              | 0           |
+-----------------------------------------------+-------------+

mysql> show variables\G;

mysql> show variables like 'max_connect%'\G;
#like表示匹配;%是通配符

更改參數:
mysql> set global max_connect_errors=110;
Query OK, 0 rows affected (0.04 sec)
#在此只是臨時更改,若是要永久更改,須要編輯配置文件

查看隊列:
mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
|  5 | root | localhost | db1  | Query   |    0 | init  | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
1 row in set (0.01 sec)

mysql> drop table t1;
Query OK, 0 rows affected (0.32 sec)

mysql> drop database db1;
Query OK, 0 rows affected (0.10 sec)

擴展:MySQL5.7之更改root密碼

與MySQL 5.6版本不一樣,在安裝MySQL 5.7過程當中(初始化)會自動生成root用戶密碼(隨機),那麼在安裝完成後如何更改root用戶密碼?步驟以下:

查看默認密碼

[root@1 mysql]# cat /root/.mysql_secret
# The random password set for the root userat Fri Jan 10 20:00:34 2014 (local time): 3A)2DdJLkcFP

更改root密碼:已知默認密碼

使用默認密碼登陸:
[root@1 mysql]# /usr/local/mysql/bin/mysql -uroot -p'3A)2DdJLkcFP'
Welcome to the MySQL monitor.  
Your MySQL connection id is 3
Server version: 5.7.17

設置新密碼:
方法1:
mysql> set password = password('123456');
Query OK, 0 rows affected, 1 warning (0.00 sec)
方法2:
mysql> SET PASSWORD FOR 'root'@localhost = PASSWORD('123456');
mysql> quit
Bye

Finished!

更改root密碼:不知道默認密碼

編輯配置文件:
[root@1 mysql]# vi /etc/my.cnf

[mysqld]
skip-grant-tables
datadir=/data/mysql
socket=/tmp/mysql.sock
#增長參數:skip-grant-tables

重啓:  
[root@1 mysql]# /etc/init.d/mysqld restart

登陸:此時不須要密碼
[root@1 mysql]# /usr/local/mysql/bin/mysql -uroot 

更改密碼:
mysql> update user set authentication_string=password('12456') where user='root';
mysql>quit

[root@1 mysql]# vi /etc/my.cnf
[mysqld]
datadir=/data/mysql
socket=/tmp/mysql.sock

重啓: 
[root@1 mysql]# /etc/init.d/mysqld restart

Finished!

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