Re: more on delete from join
Date: Thu, 3 Sep 2009 00:50:33 -0400
"Marshall" <marshall.spight_at_gmail.com> wrote in message news:badf422a-cd2b-40f1-869b-c0a248363088_at_u36g2000prn.googlegroups.com...
I guess I see what you mean, but strictly speaking it doesn't seem to fit the definition. In abductive reasoning, one knows a -> b, and b, but one doesn't know that it was in fact a that implied b. Whereas with a view, we do know.
For an insert into a union view, one knows a -> c \/ b -> c and c, but one doesn't know whether it was in fact a or b or both that implied c.
For a delete from a join view, one knows ~a -> ~c \/ ~b -> ~c and ~c, but one doesn't know whether it was in fact ~a or ~b or both that implied ~c. Received on Wed Sep 02 2009 - 23:50:33 CDT