MySQL Restore Dump

What is a MySQL Dump?

The mysqldump client tool creates a collection of SQL statements that may be run to replicate the original table data and database object definitions after performing logical backups. It dumps one or more MySQL databases to back up or move to another SQL server. Moreover, the mysqldump command can produce output in XML, CSV, or another delimited text format.

Why do we need to restore a MySQL dump?

• Data Recovery: Recovering lost or corrupted data is a major motivation for restoring a MySQL dump. You can utilize a backup dump to restore the database to a previous, known-good state if data is inadvertently lost, altered, or corrupted because of hardware malfunctions or software mistakes.
• Disaster Recovery: Having MySQL dumps on hand makes it possible to reconstruct your database on a different server or infrastructure in the event of catastrophic occurrences like server crashes, data center outages, or natural catastrophes. It is essential to the planning process for disaster recovery.
• Testing and Development: MySQL dumps are useful for building testing and development environments that replicate the production database. A database replica allows developers to work with it without affecting production data. Dump restoration is crucial to ensure data consistency across development, testing, and production environments.
• Migrations and Upgrades: When switching to a new server, database version, or environment, your data must frequently be transferred. Whether the platform or configuration changes, restoring a MySQL dump is a popular way to migrate data between several MySQL instances.
• Point-in-Time Recovery: With MySQL dumps, you may do point-in-time recovery, which lets you restore the database to a particular point in time instead of just the most recent backup. Recovering from data corruption or unintentional alterations can be facilitated by this.
• Schema Changes and Rollbacks: Restoring a dump from a period before making major changes to your database schema, including adding or deleting tables or columns, may be a means to get the schema back to how it was before the problems occurred.
• Data Archiving: MySQL dumps can be used to make snapshots of your data at different periods, which is useful when you need to archive historical data or keep a record of a certain database state for compliance or historical reasons.
• Data Validation and Testing: MySQL dumps can be used to verify your data's accuracy, consistency, and integrity. This is necessary to guarantee that your database stays dependable and satisfies corporate needs.
• Security and Data Protection: Regular backup creation may be necessary to safeguard sensitive data. If ransomware attacks or other security incidents harm your data or take it hostage, restoring a dump can help you restore it.

What is the difference between logical and physical backups?

A server-based copy of storage is called a database backup. Unplanned data loss is avoided using backups. It is simple to retrieve original data with the aid of a backup if it is lost. There are two types of database backup:

1. Physical back up
2. Logical Backup

Physical Backup

Databases are stored and recovered via physical file backups or physical database backups. Examples are various data files, control files, archived redo logs, and many more. Physical backup data is typically stored on a disc, magnetic tape, offline storage, or the cloud.

Logical Backup

Logical data that is taken from the database is contained in it. It has a table, function, procedure, and view. This is helpful when users wish to move a copy of the database to another location or restore it. When preventing data loss, logical backups are less secure than physical backups. It just offers structural specifics. Complete logical backups ought to be carried out once a week. The usage of logical backups enhances a physical backup.

How to create a MySQL dump using the 'mysqldump' command?

For creating a MySQL dump, follow the steps.

1. Open a Command Prompt or Terminal

First, open the Command Prompt or PowerShell on the Windows operating system.

2. Syntax 'mysqldump'

Following is the basic syntax for the 'mysqldump.'

mysqldump -u [username] -p [database_name] > [dump_file].sql

3. Running the 'mysqldump' Command

Type the following command in the terminal.

mysqldump -u myuser -p mydatabase > mydatabase_dump.sql

After you enter this, you will be prompted to enter the 'myuser.'

4. Verification

There should not be any error messages displayed in the terminal when the dump procedure is finished. You can look up the dump file in the working directory (mydatabase_dump.sql in the case above). The SQL commands required to reconstruct the database and its contents should be included.

How to restore a MySQL dump using the 'mysql' command?

Restore the database:

mysql -u [user name] ?p [target_database_name] < [dumpfilename.sql]

The parameters include:

• -u [user name]: This connects the username to the MySQL server.
• -p: This is used for the password to the given username to connect to the MySQL server.
• [target_database_name]: This recognizes the empty database you want to load data from the backup file.
• <: This is used to refer to the process of a database restoration.
• [dumpfilename.sql]: This indicates the path to the dump file.

Thus, to restore the Sakila database, execute the following command.

mysql --host=dbfmylast --user=root --port=3306 -p sakila < D:\sakila.sql

To check the result, run the following command

mysql> use sakila; ? mysql> show tables;

Output



Using mysqldump, restore every database in MySQL from the dump file:

You can bulk restore all the server's databases with the mysqldump tool, not just one. To restore every MySQL database from a dump file, use the following syntax:

mysql -u root -p < alldatabases.sql

In the above command, alldatabases.sql is the path of the dump file that houses a server-wide backup of every database.

Using mysqldump, restore one table from the dump file:

A particular MySQL table may occasionally need to be restored from the database because it was dropped or its contents were overwritten.

Use the mysqldump command to create a backup copy of the working hours table from the Sakila database for demonstration purposes. The output file containing the table backup is called backup_working_hours_table.sql.

mysqldump --host=dbfmylast --user=root --port=3306 -p sakila working_hours > D:\backup_working_hours_table.sql

After creating the backup, drop the working_hours table with the DROP TABLE statement.

mysql> drop table working_hours;

To check the result, run the following command

mysql> use sakila; ? mysql> show tables;

Output



Now, use the mysql command to restore the working hours table backup into the Sakila database:

MySQL --host=dbfmylast --user=root --port=3306 -p sakila < D:\backup_working_hours_table.sql

The table will be imported into the Sakila database:



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