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This article mainly introduces why the data in the database is inconsistent, the article is very detailed, has a certain reference value, interested friends must read it!

In the database, the root cause of data inconsistency is data redundancy. Data redundancy refers to the duplication of data; due to the repeated storage of data, it is easy to cause data inconsistency when different applications use and modify different backups.

Data redundancy is the root cause of data inconsistency.

Generally, there are three reasons for data inconsistency in the database:

The first is caused by data redundancy.

The second is caused by improper concurrency control.

The third is data loss or data corruption due to some reason (such as hardware and software failures or operational errors).

The first case: data redundancy

Data redundancy refers to the duplication of data, or the phenomenon that the same data is stored in different data files.

Due to the repeated storage of data, it is easy to cause data inconsistency when different applications use and modify different backups.

If both tables in the database put the user's address, when the user's address changes, if only one table's data is updated, then the two tables have inconsistent data.

The second case: improper concurrency control

If in the air ticket booking system, if two purchase points inquire about the booking of a certain ticket at the same time, and the ticket is ordered separately, if the concurrency control is improper, it will cause the same ticket to be sold to two users. Due to the lack of concurrency control or improper concurrency control in the system, the data is inconsistent.

The third case: faults and errors

If the hardware and software failure or operation errors lead to data loss or data damage, resulting in data inconsistency. Therefore, we need to provide some measures for database maintenance and database data recovery. According to various database maintenance methods (such as rollover, logs, etc.) and data recovery measures, the database should be restored to a correct, complete, consistent state.

The above is all the contents of the article "Why are the data inconsistent in the database"? thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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