Re: SUPPORT FOR DECLARATIVE TRANSITION CONSTRAINTS

Brian Selzer wrote:

>SUPPORT FOR DECLARATIVE TRANSITION CONSTRAINTS
>
>A proposed enhancement to D
>
>By Brian S. Selzer
>
>ABSTRACT
>
>A non-procedural mechanism is proposed for declaring transition
>constraints using set-based relational operators, without altering
>relvar headings and independent of whether updates affect keys.

[...]

  Brian,

You still misunderstand the fundamental objection against you proposal (which hasn't really changed in the time I've been following this newsgroup). The objection is that no matter what mechanics you add within a database, there is fundamentally no way to ensure from within the database that its statements remain up to date with changes to states of affairs in the world. No matter what kind of database I use to record information about comp.database.theory and no matter what kinds of constraints it will support, that database fundamentally has no way of knowing whether any given posting written by 'Brian Selzer' is written by the original Brian or an imposter posting under the same name. Adding a PERSON_ID allows you to *express* that problem, but it doesn't allow you to solve it. Adding constraints on what transactions may do, as you propose here, doesn't solve it, either. And nothing else will.

-- 
Reinier