On specialization constraints time of application
Date: Wed, 10 Jun 2009 06:07:07 -0700 (PDT)
Lately, I stumbled about the problem of how constraints are to be implemented in the case of relations runtime-only (I call them virtual - they can *roughly* be assimilated to functions/views) representations. I thought that it is necessity for a TRDBMS to allow the implementation of constraints over the domains of attributes that are part of these relations. As a consequence, the question came out about the modalities of constraint implementations in declarative mindset:
> Since a TRDBMS should allow constraint specialization in a declarative way, how could a TRDBMS allow constraint declaration of virtual relations in a way that does not require a representation of the virtual relation in order to validate that its constraints are verified.
I would to have the opinion of some people here and any material that
dealt with the specific subject at hand.
> Are virtual relations to be considered a part of the database relation.
> So far, I have by default taken the approach of considering attributes of virtual relations as being subjected to ANY constraint that carries on some attribute that allows these attributes to be built. I wander about the risks and opportunities of such approach and whether some work has been done on that subject.
I would to have the opinion of some people here and any material that dealt with the specific subject at hand.
Thank you/Received on Wed Jun 10 2009 - 15:07:07 CEST