Re: Guessing?
From: paul c <toledobysea_at_ac.ooyah>
Date: Mon, 26 May 2008 20:46:22 GMT
Message-ID: <ykF_j.296174$pM4.159311_at_pd7urf1no>
>
> In my opinion the Assignment Principle is more important than being able to
> update views that shouldn't be updatable. If you issue an update, and are
> informed that it succeeded, then you should be able to expect that what you
> changed actually changed. For example, if I insert a row, and the insert
> succeeds, then when I re-read the row, I should be able to determine whether
> another user changed it by simply comparing the values I inserted to the
> ones read out: if they're different or nonexistent, then someone else
> changed or deleted it.
> ...
Date: Mon, 26 May 2008 20:46:22 GMT
Message-ID: <ykF_j.296174$pM4.159311_at_pd7urf1no>
Brian Selzer wrote:
> "paul c" <toledobysea_at_ac.ooyah> wrote in message
> news:09p_j.294813$pM4.94170_at_pd7urf1no...
...
>> It is becoming more and more apparent to me that the Assignment Principle >> is a case of wanting to have your cake and eat it too. >>
>
> In my opinion the Assignment Principle is more important than being able to
> update views that shouldn't be updatable. If you issue an update, and are
> informed that it succeeded, then you should be able to expect that what you
> changed actually changed. For example, if I insert a row, and the insert
> succeeds, then when I re-read the row, I should be able to determine whether
> another user changed it by simply comparing the values I inserted to the
> ones read out: if they're different or nonexistent, then someone else
> changed or deleted it.
> ...
Sorry, slip of the keyboard, I didn't mean to mention the Assignment Principle (which is okay by me) rather what I remember being called the Principle of Interchangeability. The latter sounds wise, accepting and maybe even politically correct in some circles but I do think it is wishful thinking and suspect it is founded on quicksand.
Regarding the Assignment Principle, I say that in this case it is not violated, assuming we are talking about relational algebra that is closed. Received on Mon May 26 2008 - 22:46:22 CEST