Locking (was Re: refreshing the GUI)

[Phillip J Shelton]

Derek Atkins wrote:

> Phillip J Shelton <shelton11@dingoblue.net.au> writes:
>
>
> > Would something like having user A have the only permissions to
> > change things if they opened the account first be a usefull first
> > pass. Or is that too simple?
>
> How does the UI know whether the user intends to make changes?  I
> think this is a rather simplistic view, unfortuately.

OK.

I hope you don't mind me thinking out aloud.

> You want to
> allow multiple people to READ the data at the same time, but you
> only want one to be able to WRITE data at a time.

Yes.  If it came across that I didn't mean that, I am sorry.

> A CVS model is what I was trying to suggest, where two people could
> theoretically be changing data at the same time, however the first
> person to commit the change will lock the db (thereby serializing the
> process) and the second commit will fail because the data was changed
> from under it.

Are you thinking of `locking ' at the transaction level or account
level.  The example that comes to mind is: One person is reconciling
last months records and someone else is entering this months
transactions.  As these modifications don't clash, the users would not
expect that a change for one would nulify the change for the other.

Phill