Relevant knowledge and operation steps for MySQL accidental deletion recovery

MySQL is currently one of the most popular databases, but during use, data is often accidentally deleted. Once such a situation occurs, database accidental deletion recovery is required to ensure data integrity and security. This article will introduce the relevant knowledge and operation steps of MySQL accidental deletion recovery.

1. Preparations before MySQL accidental deletion recovery

Before performing MySQL accidental deletion recovery, we need to make the following preparations:

1. Back up the database and tables structure. Before performing any database operations, be sure to back up the original database and table structure. This is an important guarantee to prevent irreversible accidental deletion.

2. Understand the manifestations of accidental deletion in MySQL. Generally speaking, MySQL accidental deletion can be divided into two situations: physical accidental deletion and logical accidental deletion. Physical accidental deletion refers to direct deletion of database files, while logical accidental deletion refers to accidental deletion of data records or mistaken execution of DELETE statements.

3. Choose the appropriate recovery method. Depending on the accidental deletion, different recovery methods need to be selected. In the case of physical accidental deletion, you need to use professional tools to restore the backup data; in the case of logical accidental deletion, you can use system log records or start transactions to recover data.

2. Database recovery method for accidentally deleted physical files

1. Use professional recovery tools

If the data is lost due to accidental deletion of database files, you can only use professional recovery tools Tools to recover data. Commonly used tools include EaseUS Data Recovery Wizard, Recuva, etc. These tools can scan the hard drive, find accidentally deleted database files, and recover accidentally deleted data.

2. Use MySQL built-in tools

In MySQL, there is a built-in tool called the InnoDB table recovery tool, which can help users recover a physically accidentally deleted database. When you find that the database is lost, you can use the following command to check for incorrect or damaged data:

mysqlcheck –r dbname

When you check for incorrect or damaged data, use the following command to recover the data:

mysqlcheck –r dbname –repair

3. Database recovery method for logical accidental deletion

1. Use system log records to restore data

If a single or partial data record is accidentally deleted, you can use MySQL's system log records to recover data. To restore data, the specific method is as follows:

(1) Use the SHOW VARIABLES LIKE 'log_%' command to find the MySQL log path.

(2) Enter the corresponding log folder and search for the log file containing the accidental deletion operation.

(3) After finding the log file, check the log, find the accidentally deleted data record, and restore it to the original table.

2. Open a transaction for data recovery

When we mistakenly execute the DELETE statement but there is no COMMIT transaction, we can recover the data by opening a transaction. The specific method is as follows:

(1) Enter MySQL:

mysql -u root -p

(2) Open a transaction:

START TRANSACTION;

(3) Recover accidentally deleted data records:

INSERT INTO table_name VALUES(……);

(4) Check whether the recovered data is correct:

SELECT * FROM table_name;

(5) Submit the transaction:

COMMIT;

Summary

MySQL accidental deletion recovery is an essential skill for daily use of MySQL, but it is still difficult for some beginners. Therefore, we need to back up the data in advance and understand various recovery methods to prevent data from being deleted accidentally. Moreover, when using MySQL on a daily basis, you must operate with caution to avoid irreparable losses.

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