19, 2005 3:06 PM
To: hardhats-members@lists.sourceforge.net
Subject: Re: [Hardhats-members] Re: Wiki additions: [was: web evaluation
tool]
This is actually not true. flat tables are the abstraction presented
to the user (or programmer) with relational databases, but the
underlying storage model
--- Frederick D. S. Marshall [EMAIL PROTECTED] wrote:
Dear Matthew,
[...]
All databases exist to record an abstract model of pieces of the
world.
Databases are usually structured as files (or tables or classes),
each
of which lists entities of a similar kind, such as patients, or
I like Rick's point about metaphors here. Regardless how expressive a
model may be, the set of tools provided by a DBMS does tend to
influence the way we model. The basic data type in LISP (List
Processing) is the list, and it is no great surtprise that a LISP
programmer will be more likely to
Dear Greg,
You have put your finger on my point about MUMPS, the relational model,
the hierarchical model, and so on--they are just the raw materials.
They shape the way we solve the problems we face, but they do not
usually prevent us from solving problems. If I am an architectural
The problem is actually a little more subtle than that: The basic
problem is not one of wasted space. Think of a much simpler
abstraction, the file. When it is initially created, it may or may
not be allocated as a contiguous block (we'll ignore issues such as
striping). What happens if
-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Kevin
Toppenberg
Sent: Monday, September 19, 2005 12:37 PM
To: hardhats-members@lists.sourceforge.net
Subject: [Hardhats-members] Re: Wiki additions: [was: web evaluation tool]
So then, is the argument that relational databases store
All databases store a certain amount of empty space. Though it's
possible that an RDBMS could allocate space for entire tables, and
copy the entire table for each insert, but such a design is not very
likely. Instead, I would expect storage to be allocated using an
underlying B-tree. But
You also might want to take a look at my other post that goes into a
bit more detail on the motivation for the use of B-trees, by
comparing them to lists and balanced trees (such as red-black trees).
===
Gregory Woodhouse
[EMAIL PROTECTED]
Education is a progressive discovery
of our own
Isn't it basically an issue for optimizing for how you expect the
DBMS to be used? If you expect to process primarily queries and bulk
inserts, then it makes sense to allocate large blocks of storage than
if you expect a lot of updates of smaller records.
Oh, and I completely agree with
