SQL injection attacks can be prevented by using parameterized queries or prepared statements. Avoid using user input directly in SQL queries, as it can allow malicious code to be executed.
If a lot of operation are executed at the same time they can interfere each others.
Ex: everybody like a post on instagram at the same time, instead of going from 100 likes to 103, 101 can be registered 2 times and we get 102
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