Re: Relational Calculus Operators. TRC and DRC in details please

sibun wrote:
>
> I cant find the meanings of different Relational Calnulus operators used
> in TRC and DRC too.

The operators in the tuple calculus and domain calculus are the usual operators from first order logic (existential quantification, universal quantification, and, or, not). What is it that you don't understand about them?

> Cant understand the utility of Rel. Calculus at the
> first place.

The calculi are usually assumed to be more declarative then the algebra(s). That means that you just specify the "what" and less the "how". That is a good quality for a query language. Also (formal) reasoning for the calculi is easier than the algebra.

• Jan Hidders