Re: I am looking for references on updatable views

From: Mikito Harakiri <mikharakiri_nospaum_at_yahoo.com>
Date: 7 Oct 2005 14:28:28 -0700
Message-ID: <1128720508.894527.238030@z14g2000cwz.googlegroups.com>

"Show me your view update strategy, and I'll prove it failing on my example"

The example I have in mind is very simple. Consider

rename( X(t,v), v->w ) = Y(t,w)

If we update the view Y, what modification to the relation X data should be? This might seem absurdly naive example, since the view equation solves in a moment

X(t,v) = rename( Y(t,w), w->v )

Not so fast, however. Let <v=w> be (an infinite) binary relation {(v,w) | v=w}. Then, the first view equation can be written as

project_t_w(X(t,v) join <v=w>) = Y(t,w)

Y is still a perfectly updateable view, but suddenly, the method of solving this equation becomes not obvious. Received on Fri Oct 07 2005 - 16:28:28 CDT