Sanjeev Sabhlok's notes on technology, hardware, gardening

How to backup and restore mySQL

[From Downtownhost]

 
If you have shell or telnet access to your web server, you can backup your MySQL data by using the mysqldump command. This command connects to the MySQL server and creates an SQL dump file. The dump file contains the SQL statements necessary to re-create the database. Here is the proper syntax:
$ mysqldump –opt -u [uname] -p[pass] [dbname] > [backupfile.sql]
  • [uname] Your database username
  • [pass] The password for your database (note there is no space between -p and the password)
  • [dbname] The name of your database
  • [backupfile.sql] The filename for your database backup
  • [–opt] The mysqldump option
For example, to backup a database named 'Tutorials' with the username 'root' and with no password to a file tut_backup.sql, you should accomplish this command:
 
$ mysqldump -u root -p Tutorials > tut_backup.sql
 
This command will backup the 'Tutorials' database into a file called tut_backup.sql which will contain all the SQL statements needed to re-create the database.
With mysqldump command you can specify certain tables of your database you want to backup. For example, to back up only php_tutorials and asp_tutorials tables from the 'Tutorials' database accomplish the command below. Each table name has to be separated by space.
 
$ mysqldump -u username -p Tutorials php_tutorials asp_tutorials > tut_backup.sql
 
Sometimes it is necessary to back up more that one database at once. In this case you can use the –database option followed by the list of databases you would like to backup. Each database name has to be separated by space.
 
$ mysqldump -u username-p –databases Tutorials Articles Comments > content_backup.sql
 

Restoring your MySQL Database

 
Above we backup the Tutorials database into tut_backup.sql file. To re-create the Tutorials database you should follow two steps:
  • Create an appropriately named database on the target machine
  • Load the file using the mysql command:
$ mysql -u [uname] -p[pass] [db_to_restore] < [backupfile.sql]
 
Have a look how you can restore your tut_backup.sql file to the Tutorials database.
 
$ mysql -u username -p Tutorials < tut_backup.sql
 
To restore compressed backup files you can do the following:
 
gunzip < [backupfile.sql.gz] | mysql -u [uname] -p[pass] [dbname]
 
If you need to restore a database that already exists, you'll need to use mysqlimport command. The syntax for mysqlimport is as follows:
 
mysqlimport -u [uname] -p[pass] [dbname] [backupfile.sql]
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