Re: Unknown SQL

On Wed, 30 May 2001 19:56:55 -0400,
"Bob" == Bob Badour <bbadour_at_golden.net> wrote:

Bob> Object languages expose physical implementation details to Bob> programmers.
>>
>> Not the ones I have seen; most have some more abstract pointer model in
>> which
>> the pointers are certainly not bare addresses, and are more akin to
>> primary/foreign keys.

Bob> So, you are saying that all object languages use the same abstract pointer Bob> model

Of course not.

Bob> and can share OID's

Possibly.

Bob> and VTables?

No, but I don't think this is job of the OODB; I am not interested in storing methods in an OODB; I just want the data. But OODBMS advocates may well argue that their product will take care of all this.

Bob> All support exactly the same set of redundant declarations (Array, Set,
Bob> Bag, Collection) with exactly the same operators and performance
Bob> characteristics? The common interface to the base object class is the
Bob> same across all languages?  All object languages support the same forms
Bob> of inheritance?  All object languages support polymorphism in exactly
Bob> the same manner? All object languages have identical rules for which
Bob> parameters pass by reference and which pass by value?

No to all of the above, but you could adapt your 'persistent' objects to fit the OODBMSs policies/capabilities (and hopefully there'll be some standard); that's pretty much what happens with the object layers that people create (manually or automatically) for RDBMSs.

Bob> Which object languages have you used that leads you to the conclusion that Bob> they do not expose physical implementation details to programmers?

Lisp and Java and CORBA. It is definitely possible to achieve reference semantics without becoming physical.

Bob> When it comes to OODBMS vendors supporting exactly the same programming
Bob> language, they expose additional physical implementation details over and
Bob> above those inherent in the language:

yes, I agree, and that alone is enough to guarantee the lack of a OODBMS standard for years to come.

Bob> The point is: When you identify data by uniquely identifying attribute
Bob> values, you do not have to do anything to standardize. It is a priori
Bob> unnecessary.

yes, I agree, at the cost of a slight impedance mismatch (which I for one am perfectly happy with). I am still wondering whether the two models can be reconciled, because there are clearly similarities between references and keys.

                                                                      Philip

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