# Re: Concurrency in an RDB

Date: Fri, 29 Dec 2006 18:36:16 GMT

Message-ID: <Aedlh.79$c94.34_at_trndny09>

"Aloha Kakuikanu" <aloha.kakuikanu_at_yahoo.com> wrote in message
news:1167362376.998197.210150_at_i12g2000cwa.googlegroups.com...

*> Sampo Syreeni wrote:
*

> > Given the current, practical importance of both running text and the RM,

*> > I wonder why a) there haven't been any genuine attempts at treating
**> > strings, text and language in general in relational terms, or b) why the
**> > RM folks won't confess it can't be done, given the current state of
**> > knowledge, thereby acknowledging that there is data that just isn't
**> > currently amenable to relational treatment.
**>
**> What "text" do you have in mind? A set of strings is formalized nicely
**> as Kleene algebra. relational algebra is also Kleene algebra.
**>
**> Seriously, the parallels between Kleene algebra and relational algebra
**> (in Codd's definition, not Tarski:-) are remarkable. If one accepts
**> that join and union are the 2 fundamental operators of relational
**> algebra, and agrees that Kleene star is somewhat less important
**> operator, than both algebras hinge on join and union. The fundamental
**> difference is that relational join is commutative, while Kleene's is
**> not.
**>
*

What's a good way to learn Kleene Algebra? Received on Fri Dec 29 2006 - 19:36:16 CET