MySQL concurrence

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jmberrueta
Forum Newbie
Posts: 4
Joined: Wed Aug 08, 2007 9:42 pm

MySQL concurrence

Post 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
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kaszu
Forum Regular
Posts: 749
Joined: Wed Jul 19, 2006 7:29 am

Post 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
jmberrueta
Forum Newbie
Posts: 4
Joined: Wed Aug 08, 2007 9:42 pm

Post by jmberrueta »

amazingly fast... amazingly simple...
thanks kaszu for both, the actual solution and the link you provided me
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