Re: Navigation question
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Wed, 21 Feb 2007 15:28:03 GMT
Message-ID: <7yZCh.9058$R71.140171_at_ursa-nb00s0.nbnet.nb.ca>
>>On Feb 21, 2:01 am, mAsterdam <mAster..._at_vrijdag.org> wrote:
>>
>>>dawn wrote:
>>>
>>>>In another thread "navigation" is again mentioned as undesirable.
>>>
>>>Navigation is from here to there.
>>>Things like distance, direction, movement, traveling time, location,
>>>path and space are relevant concepts.
>>>
>>>In RM the database (at the logical level(*)) is a single-point
>>>thing. No navigational term has any meaning in a
>>>single point. Conversely, non of the RM terms
>>>have any navigational meaning.
>>
>>Agreed. So, this discussion about navigation is outside of the RM.
>>
>>
>>>(*) Some may maintain that the RM covers no other level.
>>> A lower, physical level is implied, and AFAIK most
>>> book that cover RM also touch it. A lot of
>>> navigation is going on at that level. Without further
>>> qualification, every navigational remark is, by default
>>> about that level, the physical level.
>>>
>>>Nothing good, nothing bad here, just: navigation is something that
>>>does not exist within the RM.
>>
>>Right. I do not know if navigation is often spoken ill of in this
>>forum 1) because it is outside of the RM 2) for the same reasons that
>>it is outside of the RM, whatever those might be or 3) for other
>>reasons. I'm trying to understand what about database navigation is
>>considered "bad" and why.
Date: Wed, 21 Feb 2007 15:28:03 GMT
Message-ID: <7yZCh.9058$R71.140171_at_ursa-nb00s0.nbnet.nb.ca>
Walt wrote:
> "dawn" <dawnwolthuis_at_gmail.com> wrote in message > news:1172066290.728188.161780_at_q2g2000cwa.googlegroups.com... >
>>On Feb 21, 2:01 am, mAsterdam <mAster..._at_vrijdag.org> wrote:
>>
>>>dawn wrote:
>>>
>>>>In another thread "navigation" is again mentioned as undesirable.
>>>
>>>Navigation is from here to there.
>>>Things like distance, direction, movement, traveling time, location,
>>>path and space are relevant concepts.
>>>
>>>In RM the database (at the logical level(*)) is a single-point
>>>thing. No navigational term has any meaning in a
>>>single point. Conversely, non of the RM terms
>>>have any navigational meaning.
>>
>>Agreed. So, this discussion about navigation is outside of the RM.
>>
>>
>>>(*) Some may maintain that the RM covers no other level.
>>> A lower, physical level is implied, and AFAIK most
>>> book that cover RM also touch it. A lot of
>>> navigation is going on at that level. Without further
>>> qualification, every navigational remark is, by default
>>> about that level, the physical level.
>>>
>>>Nothing good, nothing bad here, just: navigation is something that
>>>does not exist within the RM.
>>
>>Right. I do not know if navigation is often spoken ill of in this
>>forum 1) because it is outside of the RM 2) for the same reasons that
>>it is outside of the RM, whatever those might be or 3) for other
>>reasons. I'm trying to understand what about database navigation is
>>considered "bad" and why.
> > You've got it backwards, Dawn. > > The defects of user specified navigation were discovered first, and the > application of the RM to the problem of alrge shared data banks was > developed in order to overcome these defects.
Please don't feed the trolls. Received on Wed Feb 21 2007 - 16:28:03 CET