On 12/16/05, Ovid <[EMAIL PROTECTED]> wrote: > Minor nit: we're discussing to the relational algebra and not the > relational Calculus (unless the topic changed and I wasn't paying > attention. I wouldn't be surprised :)
Algebra, in general, is a specific form of calculus. So, we're speaking of the same thing, just in different terms. > > > * The domain of acceptable values (potentially infinite) > > > * Selectors to cast to and from the value > > > * Operators and their behaviors > > > > I would argue that you don't have selectors, by default. You > > should have to explicitly add a selector. Otherwise, into > > C-land you will go, my son! > > I'm not entirely sure, but I think we agree here. You have to have, at > minimum, one selector for each new datatype if for no other reason than > to cast a string to your new data type. Otherwise, your data types > would only be constants because you would have no way of assigning a > value. Fair enough. One would need to be able to convert back and forth between the base type (Int, String, etc) and the type. Rob
