Questions about concurrency in PHP

Questions about concurrency in PHP

Does MySQL have a mechanism to prevent concurrency that can be interpreted to listen to?

For example, the inventory is only 1, two users at the same time the purchase minus 1, will be negative.

But without PHP execution, let SQL do this operation A=a-1 ... where a>0 can be solved.

This knowledge is relatively scarce, do not know if there are predecessors of the post can be viewed, thank you



------Solution--------------------
http://ourmysql.com/archives/857
http://www.orczhou.com/index.php/2010/06/mysql-innodb-source-code-sync-1/
Http://www.cnblogs.com/perfectdesign/archive/2009/12/05/1617508.html
------Solution--------------------
MYSQL has concurrency mechanism to prevent access conflicts between different users

Let SQL do this operation A=a-1 ... where a>0 can prevent the existence of a negative stock

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