Database recovery

备份

表结构

首先,Enter in the directory where the file is to be storedcmd,Press Enter to enter the command line for operating the directory

After entering the command line
mysqldump命令 备份文件

Note here that my original database name isjx_db
because of special symbols_Therefore, an error that the database cannot be found will be reported during backup,So I copied this database named jxdbnormal backup！

mysqldump -u root -p jxdb > jxdb_bk_20211205.sql
mysqldump -u root -p jxdb student> student_bk.sql

恢复

Recovery here is what I usemysql source命令 As for how to use the other directlymysql -uroot I failed with such command…不知道为啥
原表为

删除一行：
有外键约束,The foreign key constraint must be closed before it can be deleted normally

SET FOREIGN_KEY_CHECKS = 0 ;
DELETE FROM student WHERE sno = 15202101;

恢复student表：

use jxdb;
source X:\ProgramData\SqlBackUp/student_bk.sql

恢复成功！

Note that we do not need to log in when we back upmysql的,
When backing up, you can directly perform command line operations in the directory, but you must log in first when restoringmysql,Restore used heresourcecommand and specify the database

导出

SELECT * FROM sc INTO OUTFILE 'C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/SC_out.txt';

导出时报错：
The MySQL server is running with the --secure-file-priv option so it cannot execute this statement

The reason for the error was found to be the installationmysqlSecurity permissions are restricted,这个选项设置系统变量： secure_file_priv,这个变量被用于限制数据导入的导出操作
用SHOW VARIABLES LIKE “secure_file_priv”;Check out our file paths

解决方案
解决办法
将文件导入到value的目录下 并且要注意sqlUse slashes in statements\才可以！

SELECT * FROM sc INTO OUTFILE 'C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/SC_out.txt';

导入

报错：
Loading local data is disabled; this must be enabled on both the client and server sides

Check to see if import permission is turned on

SHOW GLOBAL VARIABLES LIKE 'local_infile';

change this value to ON,在mysql客户端输入:

set global local_infile=1;

Specify the original path to the file import table！
成功！

LOAD DATA LOCAL INFILE 
'C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/SC_out.txt' 
INTO TABLE sc 

也可以导出为html
SELECT * FROM course INTO OUTFILE
‘C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/course_html.html’;