How to implement pessimistic locking in mysql?

Mysql pessimistic lock method: 1. First use [select ... for update] to lock, and after the operation is completed, use commit to release the lock; then the innodb engine defaults to the row-level lock; finally no data can be found , just don’t lock the table.

mysql pessimistic lock method:

1. Start transaction

begin;/begin work;/start transaction; (三者选一就可以)

2. Query Output product information

select status from table where id=1 for update;

3. Generate order based on product information

insert into table111 (id,goods_id) values (null,1);

4. Modify product status to 2

update table set status=2 where id=1;

5. Submit transaction

commit;/commit work; (任选一种释放锁)

Summary:

1. Implement pessimistic locking using select... for update to lock, and use commit to release the lock after the operation is completed;

2. Innodb engine, by default Row-level locking, when there is a clear field, a row will be locked, if there is no query condition or condition;

When the field is unclear, the entire table will be locked, and when the condition is a range, the entire table will be locked;

　3. When no data can be found, the table will not be locked.

Related learning recommendations: mysql video tutorial

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