Re: Unknown SQL

On Sat, 12 May 2001 07:07:24 -0400,
"Bob" == Bob Badour <bbadour_at_golden.net> wrote:

>> And in fact, from a pragmatical point of view, the fact that RDBMSs are
>> largely standardized, it is much easier to switch to different languages or
>> even RDBMS vendors. Same can not be said for OODBMSs. Some argue that this
>> is not a strength of the relational model, but rather a failure (since
 Bob> what?
>> 10 years?) on the part of the OODBMS vendors to get their act together on
 Bob> the
>> standardization front. Others will argue that it _is_ easier to standardize
>> implementations of well understood technology such as relational theory,
 Bob> and
>> that object oriented persistence is difficult simply because there is no
>> overarching formal theory for objects.

Bob> Philip,

Bob> It is not an issue of theory, per se, that makes it easy to switch between Bob> RDBMSs and hard to switch between network model OODBMSs.

well, I don't really know. On the face of it, I agree. But I have the suspicion that the fact that relational theory is well understood and 'closed', does make it easier to standardize. So although one can criticize the OODBMS vendors for not getting their act together regarding standardization, maybe we have to cut them some slack and blame the OODBMS 'model' (partly) for it.

Bob> Moving from one vendor's RDBMS to another vendor's RDBMS, the value 1
Bob> likewise remains the value 1. Similarly, the value 346987563 remains the
Bob> value 346987563.

yes, I would hope so :-)

Bob> Network model databases, however, represent data with pointers and other
Bob> physical constructs that vary greatly among different vendors. Further
Bob> issues such as shallow copies vs. deep copies, pointer swizzling, implicit
Bob> back-pointers etc. vary as well. Every different implementation of network
Bob> model database changes the meaning of the data implied by physical
Bob> constructs by introducing often subtle differences in interpretation.

yes. Which incidentally points to an advantage of using (primary/foreign) keys, rather than pointers: they are inherently more portable, and you can even communicate them by phone (which is what you basically do when quoting your customer number or reference number etc.).

Cheers,

                                                                      Philip

-- 
If you have a procedure with 10 parameters, you probably missed some. (Kraulis)
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