Re: [ShopSuite-dev] new shop.psql

[Tomasz Wegrzanowski]

On Tue, Aug 21, 2001 at 08:07:47PM +0100, Davi Leal wrote:
> > There's a question whether we need active if we have inactivation
> > that may be NULL. I prefer second version, as active field gives no new 
> > data.
> > Following is always true:
> >     active ::= (inactivation != NULL)
> 
> The "products.active ::= (transform.inactivation != NULL)" rule is wrong. I
> think you mix the 'products' and 'transform' tables. On the one hand, the
> 'active' field of the table products means if a product has been removed or 
> not,
> that is to say, if it is active or not. On the other, the 'inactivation' field
> of the table transform shows if a 'transformid' is history, that is to say, 
> its
> 'inactivation' field IS NOT NULL; or if it is the current transform, that is 
> to
> say, its inactivation IS NULL. See below, and see the attached xfig figure.

Oops, you're right.