Re: native xml processing vs what Postgres and Oracle offer
Date: Mon, 1 Dec 2008 17:09:38 -0500
>> "paul c" <toledobythesea_at_oohay.ac> wrote in message >> news:nUeXk.560$si6.520_at_edtnps83... >>> rpost wrote: >>>> paul c wrote: >>>> >>>>> patrick61z_at_yahoo.com wrote: >>>> [...] >>>> >>>>>> Actually, usenet is often displayed as being hierarchical, for >>>>>> instance with so called "threaded" newsreaders, because within a list >>>>>> of discussions, replies to replies are often more comprehensible when >>>>>> you can follow the subthreads. >>>>>> ... >>>>> Nobody said there's anything wrong with hierarchical displays (or >>>>> hierarchical physical storage for that matter). >>>> [...] >>>> >>>>> As the general level of literacy continues to decline more and more of >>>>> those who fail to recognize the possibility of a logical model will >>>>> have >>>>> to put up with that dwindling breed. >>>> You're evading the question. >>>> ... >>> What question would that be? (The original question was to do with the >>> best product to use to display hierarchical data. The OP planned to >>> invent his own forum, presumably not Usenet-based. I pointed out that >>> he was wrong to assume a forum is hierarchical.) >>> >> >> Pardon me for sticking my nose in, Paul, but you are ignoring facts as >> plain as day: The content of a forum is a directed graph without any >> circuits--that is, a collection of trees--each message being a node and >> each response being a directed edge. How can you possibly argue that it >> is not heirarchical? >> >
> I'm amazed that in this day and age there can be any dispute about
> something so simple. As I said before, one may choose to display messages
> in a hierarchical way, but that is not at all the same thing as basing a
> server or reader on a hierarchical model.
I didn't say anything about a heirarchical model. I'm arguing that the content of a forum--messages and responses to messages--is in essence heirarchical. This is not about how messages are displayed, it's about what they are: each message either starts a topic or is a reply to another message.
> The essence of a hierarchy is position and record order. Position ignores
> the Information Principle and the order is logically extraneous.
The essence of a heirarchy is precedence. A heirarchy is a collection of individuals (objects) connected in such a way that each individual has at most one direct predecessor and that no individual can be a direct or indirect predecessor of itself. Records and the position of records are at best orthogonal.
> Hierarchical implementations depend on pointers or adjacency or both.
> Without those, some, maybe most, hierarchies are limited to a single
> presentation. A relational implementation doesn't have that problem.
> If you believe that the horizon is flat and airplane window glass makes it
> appear as a curve then it might be accurate to conclude that the earth is
> flat, but it wouldn't be pertinent. Same goes for starting with the
> belief that hierarchy is inherent in the typical forum's actual messages.
> If that were so, it would just as reasonable to say that every Accounts
> Receivable data model must be a hierarchy.
Received on Mon Dec 01 2008 - 23:09:38 CET