Re: A numerical methods viewpoint on OO/FP/Relational

In article <3b44a4a2$1_at_tobjects.newsource.com>, peter_douglass says...
>
>> Relational model:
 

>> The relational model is declarative. It defines the variables
>> and defines the constraints that the variables must satisfy.
>> It doesn't say how these constraints must be satisfied.
>> It simply accepts or rejects values for the variables depending
>> on whether these values satisfy the constraints or not.
 

>> Note, however, that the relational model also has a
>> provision for explicitly defining dependent variables as
>> functions of other variables.

This definition is too broad for Relational, you essentially describe Constraint Databases. Relational narrows it's scope to very simplistic (and highly successful, as well:-) kinds of predicates.

>
>IMHO, one of the weaknesses of many FPLs is lack of explicit relational
>support. The experimental language Machiavelli, is in my opinion, a step in
>the right direction. From another angle, Functional-Logic programming
>languages like Mercury allow functions and constraints to be used in the
>same language.
>

Very helpful comment for me, because I was just figuring out why there is no such thing as Haskell Database Connectivity driver... Received on Fri Jul 06 2001 - 02:29:38 CEST