How to properly avoid Mysql Race Conditions

Question

I know this has been asked before, but I\'m still confused and would like to avoid any problems before I go into programming if possible.

I plan on having an interna

Answer 1

To achieve this, you will need to lock the record somehow. Add a column LockedBy defaulting to 0.

When someone pushes the button execute a query resembling this:

UPDATE table SET LockedBy= WHERE LockedBy=0 and id=;

After the update verify the affected rows (in php mysql_affected_rows). If the value is 0 it means the query did not update anything because the LockedBy column is not 0 and thus locked by someone else.

Hope this helps