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MySQL concurrence

Posted: Sun Aug 26, 2007 12:49 pm
by jmberrueta
Hi everyone. I hava a script that needs to update a value in a database (let's say, for example, add 1 to the value of a field). So, I first need to read the value in that fileld, increase it, and update the field. In the meantime, such script may be called by another user. Is that posible? If so, the read value might change before the field update is done...
How can that be solved? Is there any php/mysql blocking for that?

Thanks in advance

Posted: Sun Aug 26, 2007 1:28 pm
by kaszu
If you need just to update by 1 you can use

Code: Select all

UPDATE my_table SET field_1 = field_1 + 1 WHERE ...
Have a look at http://dev.mysql.com/doc/refman/5.0/en/lock-tables.html for locking the tables in mysql

Posted: Sun Aug 26, 2007 1:43 pm
by jmberrueta
amazingly fast... amazingly simple...
thanks kaszu for both, the actual solution and the link you provided me