mysql way to make a lock in a php page
- by Cris
Hello,
i have the following mysql table:
myTable:
id int auto_increment
voucher int not null
id_user int null
I've populated voucher field with values from 1 to 100000 so i've got 100000 records; when a user clicks a button in a PHP page, i need to allocate a record for the user so i make something similar like:
update myTable set id_user=XXX where
voucher=(SELECT * FROM (SELECT MIN(voucher) FROM myTable WHERE id_user is null) v);
The problem is that I don't use locks and i should use them because if two users click in the same moment i risk to assign the same voucher to different persons (2 updates in the same record so i lose 1 user) ...
I think there must be a correct way to do this, can you help me please?
Thanks !
cris
