Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]
From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Thu, 23 Jun 2005 18:19:11 GMT
Message-ID: <z2Due.127998$KG6.7122024_at_phobos.telenet-ops.be>
>
> There are not query languages. Daplex and SQL are data languages.
Date: Thu, 23 Jun 2005 18:19:11 GMT
Message-ID: <z2Due.127998$KG6.7122024_at_phobos.telenet-ops.be>
Alfredo Novoa wrote:
> On Wed, 22 Jun 2005 19:12:20 GMT, Jan Hidders
> <jan.hidders_at_REMOVETHIS.pandora.be> wrote:
>
>
>>>>The words "procedural" and "imperative" are in this context largely >>>>synonymous. >>> >>> >>>They are largely confused, but not synonymous. >>> >>>http://foldoc.doc.ic.ac.uk/foldoc/foldoc.cgi?imperative+language >> >>The context in which the term was used was query languages, not update >>languages.
>
> There are not query languages. Daplex and SQL are data languages.
Alexander's words you reacted to where:
| |>>Yet, I agree that FDM queries are still different from purely |>>declarative queries.
> On the other hand a Daplex query reads the current state of variables
> and that is imperative programming.
No, it evaluates an expression for each element in a certain set of binding without the possibility of those expressions having side-effects that can influence each of those evaluations. That's called set comprehension and if you don't believe me then I'm sure a few experts in comp.lang.functional will be more than willing to explain to you why that is not imperative.
- Jan Hidders