On 17 Jan 2009, at 16:45, srj wrote:
>
> In Rails 2.2.2, if I retrieve a record using a Model.find method (any
> of the finds), make changes to it, and then save it, is there a
> possibility that another user (on a different thread, maybe a faster
> machine) could read the same record after me, but update it before
> me? If so, then the other user''s changes would be lost (a data
> concurrency problem).
Yes>
>
> How does Rails prevent this?
>
> Is there a way to do something like
> Model.save_only_if_updated_at_is_unchanged ?
> Is there a find_and_lock, find_for_update, or other similar function?
>
Look up optimistic locking.
Fred> This is different than dirty records, because it is comparing the
> record I have in my session to the same record in the database to
> ensure that *no one else* changed it.
>
> Thank you,
>
> Steve
> >
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