Re: Object-relational impedence

On Mar 8, 7:09 am, rp..._at_pcwin518.campus.tue.nl (rpost) wrote:
> TroyK  wrote:
> >Who said anything about stored procedures? I'm talking about
> >implementing the business rules via constraint declaration in the
> >database, and deriving new values throught the application of SQL
> >queries.
>
> Do you also treat dynamic constraints in this way?
>
> E.g. "unless otherwise specified, an employee shall get a 2%
> salary increase after each full year of employment".
> Or: "two movable 3D shapes shall never collide; collision is avoided
> by the following repositioning algorithm that is guaranteed
> to pull all objects apart that get too close: (...), however, this
> algorithm may be replaced with another that has the same property".
>
> --
> Reinier

Inferring the definition of "dynamic constraint" from your examples, in the first, I think that it would be sufficient to model and record whatever attribute means "otherwise specified" and include that as part of the condition in the constraint declaration.

I haven't had occasion to apply the technique to anything more complex than such an example, so I'll have to say "I don't know" to the 3D example.

TroyK Received on Mon Mar 10 2008 - 22:56:47 CET