• mysql安装及基本操作(mysql作业)


    1 官网下载,链接  https://www.mysql.com/downloads/

    Download MySQL Community Server

    默认为你选好了Mac OS X 平台

    选择的是.dmg的。点击右侧的download进行下载。

    跳转到另外一个界面,提示你需不需要注册,直接选择最下面的“No thanks,just take me to downloads!”

     安装MySQL

    安装完成后终端输入:

    $mysql -version

    -bash: mysql: command not found

     ”/usr/local/mysql/bin/mysql”为mysql默认安装路径:

    $/usr/local/mysql/bin/mysql -version

    ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

    $cd /usr/local/bin

    $sudo ln -fs  /usr/local/mysql/bin/mysql  mysql

    Password:

    $mysql  -version

    ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

    配置root账号的密码,默认没有配置,

    $ mysql -u root

    Welcome to the MySQL monitor.  Commands end with ; or g.

    Your MySQL connection id is 3

    Server version: 5.7.18 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> 

    mysql>update mysql.user  set  authentication_string = password('******') where user ='root';

    Query OK, 1 row affected, 1 warning (0.00 sec)

    Rows matched: 1  Changed: 1  Warnings: 1

    mysql> flush privileges;

    mysql> quit

    flush privileges后mysql -u root就登录不上了,需要用密码了例如下面

    $mysql -u root

    ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

    mysql -u root -p

    Enter password: 

    Welcome to the MySQL monitor.  Commands end with ; or g.

    Your MySQL connection id is 5

    Server version: 5.7.18 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> create database homework;

    ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

    出现这样的报错,解决办法:重新设置一遍密码

    mysql> set password =password('******');

    Query OK, 0 rows affected, 1 warning (0.00 sec)

    mysql> create database homework;

    Query OK, 1 row affected (0.00 sec)

    mysql> use homework;

    Database changed

    mysql> show tables;

    Empty set (0.00 sec)

    数据库的基本操作,创建数据库。

    mysql> create table Student(Sno int(10),Sname varchar(255),Ssex varchar(255),Sage int(10),Sdept varchar(255));

    Query OK, 0 rows affected (0.03 sec)

    mysql> show tables;

    +--------------------+

    | Tables_in_homework |

    +--------------------+

    | Student            |

    +--------------------+

    1 row in set (0.00 sec)

     查看创建表的信息语句:

    mysql> show create table Student;

    +---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

    | Table   | Create Table                                                                                                                                                                                                                              |

    +---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

    | Student | CREATE TABLE `Student` (

      `Sno` int(10) DEFAULT NULL,

      `Sname` varchar(255) DEFAULT NULL,

      `Ssex` varchar(255) DEFAULT NULL,

      `Sage` int(10) DEFAULT NULL,

      `Sdept` varchar(255) DEFAULT NULL

    ) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

    +---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

    1 row in set (0.02 sec)

    mysql> create table Course(Con int(10),Cname varchar(255),Cpno int(10),Ccredit int(10));

    Query OK, 0 rows affected (0.03 sec)

    mysql> show create table Course;

    +--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

    | Table  | Create Table                                                                                                                                                                                      |

    +--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

    | Course | CREATE TABLE `Course` (

      `Con` int(10) DEFAULT NULL,

      `Cname` varchar(255) DEFAULT NULL,

      `Cpno` int(10) DEFAULT NULL,

      `Ccredit` int(10) DEFAULT NULL

    ) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

    +--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

    1 row in set (0.00 sec)

    插入一条数据:

    mysql> insert into Course values('4','data structure','7','4');

    Query OK, 1 row affected (0.00 sec)

    更新一条数据:

    mysql> update Course set Cno='5' where Cname='data structure';

    ERROR 1054 (42S22): Unknown column 'Cno' in 'field list'

    发现创建的字段应该是Cno,创建错了,成Con

    更改字段:

    mysql> alter table Course change Con Cno int(10);

    Query OK, 0 rows affected (0.02 sec)

    Records: 0  Duplicates: 0  Warnings: 0

    mysql> update Course set Cno='5' where Cname='data structure';

    Query OK, 1 row affected (0.01 sec)

    Rows matched: 1  Changed: 1  Warnings: 0

    查询数据:

    mysql> select * from Course;

    +------+--------------------+------+---------+

    | Cno  | Cname              | Cpno | Ccredit |

    +------+--------------------+------+---------+

    |    1 | database           |    5 |       4 |

    |    2 | math               |    0 |       2 |

    |    3 | information system |    1 |       4 |

    |    4 | operation  system  |    6 |       3 |

    |    5 | data structure     |    7 |       4 |

    |    6 | data process       |    0 |       2 |

    |    7 | pascal             |    6 |       4 |

    +------+--------------------+------+---------+

    7 rows in set (0.00 sec)



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  • 原文地址:https://www.cnblogs.com/vincentqliu/p/6692743.html
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