Re: [PATCHES] Updatable views

Bernd Helmle wrote:

> <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> >* It's too early in the morning for me to be clear about the difference
> >between CASCADED and LOCAL CHECK OPTION --- I think that this would
> >merely alter the set of check constraints collected for a particular
> >query, but if there's something more fundamental there, this scheme
> >might not work at all. So look into that first.
>
> LOCAL checks the data to be updated against its own view WHERE
> condition only, where CASCADED involves all WHERE conditions of all
> underlying views.

I don't understand this part very well. Say if you have a view WITH
CHECK OPTION whose condition is "foo > 5", and then define a view WITH
LOCAL CHECK OPTION on top of that, whose condition is "bar > 5". Does
the local check option on the second view that I can insert a row with
foo=4, bar=6? That doesn't violate the condition of bar > 5, so it
seems fine to me. But it also seems quite idiotic because it violated
the original foo>5 condition.

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Alvaro Herrera http://www.CommandPrompt.com/
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