The complete mysqldump guide, with examples

What is mysqldump?

mysqldump is a utility program that is used to backup and restore databases in the MySQL database management system. It allows you to extract a database's contents and metadata, including tables, triggers, stored procedures, and views, into a file, which can then be used to restore the database in case of data loss. The mysqldump utility is a command-line tool, which means it can be run from a terminal or command prompt, making it a convenient and flexible way to manage database backups.

The importance of backups

Backup is one of the most crucial activities for any website or application that relies on data. A backup helps ensure the safety of your data and enables you to quickly restore your site to a previous version in case of a disaster. This makes it a critical component of your site's maintenance routine. In this article, we'll take a deep dive into mysqldump, a powerful tool for backing up MySQL databases.

How to use mysqldump

Mysqldump is a powerful tool that allows developers to create a backup of their entire database in the form of an .sql file. To utilize this tool, you must have access to the server where the MySQL instance is running and be granted the necessary privileges for exporting data. The user credentials for the database (username and password) must be provided.

There are four main ways to use mysqldump for exporting data:

• exporting specific tables within a MySQL database
• exporting a single database
• exporting multiple databases
• exporting all the databases from the MySQL server

Export specific MySQL tables using mysqldump

To export specific tables from a MySQL database, you need to run the following command:

mysqldump -u my_user -p database_name table1 table2 > tables.sql

Replace my_user with your MySQL user name, database_name with the name of the database that contains the tables, table1 table2 with the names of the tables you want to export. If you want to export more tables, just continue adding the names further. The -p option prompts for the password of the MySQL user.

Let's assume your MySQL user is luigi, the database is named my_db and you want to export the tables users and logs. The mysqldump command will look like the following:

mysqldump -u luigi -p my_db users logs > tables.sql

The tables.sql file created by mysqldump contains the SQL commands necessary to recreate the tables and the data that was exported.

Export a single database

To export a single MySQL database, you need to run the following command:

mysqldump -u my_user -p database_name > backup.sql

Replace my_user with your MySQL user name and database_name with the name of the database you want to export. The -p option prompts for the password of the MySQL user.

The backup.sql file contains the SQL commands necessary to recreate the database as it was at the export time.

Export multiple databases

In order to export multiple MySQL databases, you need to run mysqldump using the --databases flag:

mysqldump -u my_user -p --databases db1 db2 db3 > backup.sql

Replace my_user with your MySQL user name and db1 db2 db3 with the name of the databases you want to export. If you want to export more databases, just continue adding the names further. The -p option prompts for the password of the MySQL user.

Export all databases from the MySQL server

In order to export all the databases from the MySQL server, you need to run mysqldump using the --all-databases flag:

mysqldump -u my_user -p --all-databases > all_databases.sql

Replace my_user with your MySQL user name. The -p option prompts for the password of the MySQL user.

The all_databases.sql file contains the SQL commands necessary to recreate all the databases exported.

How to import a mysqldump

mysqldump creates a file that contains the data and structure of one ore more MySQL databases. This file can be used to restore the database(s) or to import the data into another database.

In order to import a mysqldump, you need to run the following command:

mysql -u my_user -p my_db < backup.sql

Replace my_user with your MySQL user name and my_db with the name of the database where you want to import the dump. The -p option prompts for the password of the MySQL user. The above command imports the data from the file backup.sql into the database my_db.

Once the import is complete, you can verify that the data has been imported by connecting to the database and querying the data.