MySQL advanced (13) command line export import database

One 、 Command line export database

• Get into MySQL In the catalog bin Folder ：cd MySQL Medium to bin Directory of folders

Like the command line I typed ：

cd D:\Program Files\MySQL\MySQL Server 5.5\bin

( Or directly windows Environment variables of path Add this directory to the )

• Export database ：
  mysqldump -u  user name  -p  Database name  >  Exported file name  

Like the command line I typed :

mysqldump -u lmapp -p lmapp -P 3308 > lmapp.sql   ( After entering, it will let you enter MySQL Password )

If you export a single table, enter the table name after the database name

mysql Export a database table

mysqldump -u  user name  -p  Database name   Table name >  Exported file name

mysqldump -u lmapp -p lmapp users> test_users.sql （ There is no semicolon at the end ）

3、 You'll see the file news.sql Automatically generate to bin Under the document   

 

Export time , Encounter the above problems .

Solutions ： Add a parameter

-P 3308

(mysql Service port ) Problem solvable .

Two 、 Command line import database

• To be imported .sql Move to file bin Under the document , Such a path is more convenient

• The same as the first one exported above 1 Step

• Get into MySQL：
  mysql -u  user name  -p

Like the command line I typed :

mysql -u root -p

   ( After entering the same, you will be asked to enter MySQL Password )

• stay MySQL-Front Create the database you want to build in , This is an empty database , If you create a new one named news The target database of

• Input ：
  mysql>use  Target database name

Like the command line I typed :mysql>use news;

• Import files ：
  mysql>source  The name of the imported file ; 

Like the command line I typed ：mysql>source news.sql; 

 

notes : Due to the size of the imported database 、 The data structure is different , The import time will vary greatly . The databases I import are 123M, It costs nearly 5 Hours . During this period, I thought the machine was down , Carefully observe the command line interface and find , Import is normal . The interface after successful import is as follows :

      

notes : When importing a single data table , Use similar use lmapp lm_area 、source lm_area.sql Of sql sentence . The original data table can exist , The imported data table will overwrite the existing data table with the same name .

MySQL Backup and restore , It's all about using mysqldump、mysql and source Order to complete . 

3、 ... and 、Win32 Next MySQL Backup and restore of  

3.1  Backup  

The start menu  |  function  | cmd | utilize “cd \Program Files\MySQL\MySQL Server 5.0\bin” Order to enter bin Folder  |  utilize “

mysqldump  -u  user name  -p databasename >exportfilename

” Export database to file , Such as

mysqldump -u root -p voice>voice.sql

, Then enter the password to start exporting . 

3.2  Restore  

Get into MySQL Command Line Client, Input password , Enter into “mysql>”, Enter the command "show databases;", enter , Look at some databases ; Build the database you want to restore , Input "create database voice;", enter ; Switch to the newly established database , Input "use voice;", enter ; Import data , Input "source voice.sql;", enter , Start import , Again "mysql>" And the restore is successful without prompting an error . 

Four 、Linux Next MySQL Backup and restore of  

4.1  Backup  

[[email protected] ~]# cd /var/lib/mysql ( Enter into MySQL The library catalog , According to their own MySQL Adjust the directory for installation ) 

[[email protected] mysql]# mysqldump -u root -p voice>voice.sql

Just enter the password .

4.2  Restore

Law 1 ：

[[email protected] ~]# mysql -u root -p  enter , Input password

Get into MySQL In the console "mysql>", Same as 1.2 Restore .

Law two ：

[[email protected] ~]# cd /var/lib/mysql ( Enter into MySQL The library catalog , According to their own MySQL Adjust the directory for installation ) 

[[email protected]&nbsp;mysql]#&nbsp;mysql&nbsp;-u&nbsp;root&nbsp;-p&nbsp;voice<voice.sql

Just enter the password .

5、 ... and 、 Extended reading   Not reliable FLOAT data type

When designing data sheets , Suddenly found that FLOAT It turned out to be very unreliable , I suggest you change to

DOUBLE

type ,

Cause analysis ： stay mysql The manual says , stay

MySQL

All calculations in are done with double precision , Use

float

( Single precision ) There will be errors , Unexpected results .

When querying data ,

MySQL

Use 64 The precision of decimal value is executed

DECIMAL

operation ,

float(5.54) = 5.54 

If precision loss occurs , This is unequal . such , The data we should be able to find will disappear inexplicably .