[Fwd: Re: [om-list] Re: System Design]

[Luke Call]

Of course I agree with you on storing it in a DB, instead of XML--I 
think we're in total agreement there. But I still keep thinking that the 
data is the model. I think this comes down to our differing views about 
how to think of the lowest level of the model. You're thinking of how to 
store logical statements, and I'm thinking I don't have to create a 
model, since the software saves objects and relations and that is the 
model--created on the fly as data is entered.  Hmmm...

Luke

-------- Original Message --------
Subject: Re: [om-list] Re: System Design
Date: Fri, 10 Nov 2000 12:52:13 -0700
From: Mark Butler <butlerm at middle.net>
To: Luke Call <lacall at onemodel.org>
References: <3A0021BB.60000 at onemodel.org> <3A021BFE.BE0D6B0B at middle.net> 
<3A0957C8.7010602 at onemodel.org>

Luke Call wrote:

 > That is exactly why I suggest we store our structures in a 3rd-party DB
 > for now. PSE was cheap and effective for a quick prototype (at leaste it
 > was a few years ago; it was a free Java OO database), and there are many
 > options to choose from.

I generally agree.  We can store our data structure in any kind of database
once we agree what it is.  The only tradeoff is efficiency depending on how
close the mapping is.  I expect that once we have a common logical model
different classes of applications could use different database types and 
data
representations to store the same information.

As an example, XML is a both a text interchange format and a logical
meta-format for hierarchically structured data.  Many modern systems 
speak to
each other in the canonical text format of XML, but no one stores any
significant amount of data that way, rather they convert it to a native
database for storage and retrieval.

Those native databases are currently mostly relational, but there are 
several
up and coming databases that can convert and store XML data in a manner
suitable for random indexed key access and processing.

XML is a bit of an ugly format, but is extremely easy to parse, which
contributes to its popularity.  Before we start mapping our proposal to a
pre-existing database, we really need to agree on a common logical 
meta-model.

A standard text based format corresponding to that representation is then
extremely valuable to insure the portability and interoperability of various
programs based on the same logical meta-model.

Some applications, for example, may only need a read only extract of
information about a particular field and good get along just fine with
importing a text extract of a more comprehensive database.

- Mark

-- 
Mark Butler	       ( butlerm at middle.net )
Software Engineer
Epic Systems
(801)-451-4583




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