Re: On view updating
From: Costin Cozianu <c_cozianu_at_hotmail.com>
Date: Tue, 21 Sep 2004 13:05:03 -0700
Message-ID: <2rbfroF18gl6lU1_at_uni-berlin.de>
>
>
> Views are variables too. Virtual variables but variables. Although a
> "closed view" has nothing of virtual to the user.
>
>
Date: Tue, 21 Sep 2004 13:05:03 -0700
Message-ID: <2rbfroF18gl6lU1_at_uni-berlin.de>
>>Since >>relvars are "variables" and the rest are computed values,
>
>
> Views are variables too. Virtual variables but variables. Although a
> "closed view" has nothing of virtual to the user.
>
>
There's no such thing as "virtual variables" in PL theory.So to avoid confusion by "my imaginary model" vs. "your imaginary model" kind of debate let's enumerate some invariants across all reasonable models
- Views have a name
- A view denotes an expression that can be evaluated or composed with
other expressions.
- views do not denote a "store".
Therefore, here you have your trivial distinction in all imperative languages between a "store" (variable, possibly aliased or non-aliased) which is your lvalue, and an expression. Received on Tue Sep 21 2004 - 22:05:03 CEST