Right. The use of B-trees does not have to do with the abstraction
(table, global) presented to the user, but how disk storage is managed
"under the hood".
====
Gregory Woodhouse
[EMAIL PROTECTED]
On Apr 15, 2005, at 9:22 AM, Richard G. DAVIS wrote:
From: "Thurman Pedigo" <[EMAIL PROTECTED]>
Organization: [EMAIL PROTECTED]
Reply-To: hardhats-members@lists.sourceforge.net
Date: Fri, 15 Apr 2005 09:54:15 -0500
To: <hardhats-members@lists.sourceforge.net>
Subject: RE: [Hardhats-members] BIG NEWS re HealtheVet- St.
Petersburg Tim es
Wow! That explains why MUMPS is so much faster then the old KFAM I
cut my
teeth on - AND why MUMPS won a "shoot-out" I set up between it and
the Pick
operating system in the 80's(anyone remember Dick Pick?). I think my
memory
is correct that $O sorted 100,000 records in less than a minute and
Pick was
still going after 30 min.
Now for the real question - where does SQL fall in this multi-way
B-tree
hierarchy?
Thanks,
thurman
Thurman, the simple answer is SQL does not fall in the underlying
B-tree
hierarchy!!!
You have been misdirected by the well meaning but equally misdirected
discussion that appeared between my response and your question.
The matter is suitable for several weeks of classes in a graduate
level IT
course, so I can't go from Kindergarten to 12th grade on this point in
a
short message here.
Nonetheless, I will make a few statements at the risk of failing to
clarify
the matter for you, Thurman.
1. The MUMPS Global system is a relatively high level abstraction that
describes the behavior of a system for managing persistent bindings
between
symbols and data. This system exists entirely in a conceptual domain
that
does not depend on any particular underlying implementation
technology, be
it "B-tree" or whatever else.
2. The relational data management system described by the Standard
Query
Language standard (SQL) is likewise a high level abstraction that
exists
conceptually in a layer that is independent of the underlying
implementation
technology, what ever that may be.
3. Discussions about relational database systems that become focused
on
such base layer technologies as "B-trees" have wondered off the
reservation
and are blindly stumbling around in the wilderness.
4. As for hierarchy in data management systems, the common 'relational
database' system, also referred to as an SQL database system, is
hierarchical!
a. Any given hierarchy can be assigned a value that reflects the
"order" of that hierarchy in an infinitely large family of hierarchies.
There can be a hierarchy of order 5, or of order 2, or of order 1.
b. A hierarchy of order 1 is the simplest order and is easily
recognized by practically anyone as a "table". A given table may have
1 or
more rows and one or more columns. (Note a simplest table is a grocery
list.) The "relational database" creators have chosen to limit that
system
to hierarchical order 1, the 'table' as the domain of elementary data
structures. This decision opens up the possibility that such a system
can
include a calculus for manipulating the data in the system where that
calculus is fully deterministic, hence completely predictable.
c. VA FileMan can be used to create a system of 'files' that are
restricted to file structures that simple tables. In this sense then
this
system of tables in FileMan corresponds structurally to a "relational
database". However, FileMan does NOT offer the calculus for operating
on
such a system of files using the SQL operations for manipulating the
data in
that system. If a FileMan system of files includes file structures
that
contain sub-files, and/or 'pointer' linkages among files, then this
system
of files is no longer of hierarchy order 1, and is not, therefore,
similar
to a 'relational database' structure.
5. In the context of superiority debates--my database management
system can
beat up on your database management system--it is important to
carefully
take into consideration the need to include mention of the underlying
technology. ...and, to know when mention of the underlying technology
is
not relevant to the debate. ...and, further to be especially careful
to
prevent the mention of underlying technology from pushing aside the
original
discussion about the relative merits of high level abstractions like
MUMPS
globals and SQL tables.
...
....
.....
......
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real
users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Hardhats-members mailing list
Hardhats-members@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/hardhats-members
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Hardhats-members mailing list
Hardhats-members@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/hardhats-members
