Re: Nested Relations / RVAs / NFNF

Marshall Spight wrote:

> "Kenneth Downs" <firstinit.lastname_at_lastnameplusfam.net> wrote in message
> news:7dfolc.m6e.ln_at_mercury.downsfam.net...

>> Marshall Spight wrote:
>> >
>> > So, on a related note, it's a little weird that we use integers as
>> > keys. Integers support e.g. addition, so we are allowed to add
>> > two keys together. This is nonsensical. Perhaps, if we want
>> > to have surrogate keys, something different from integers
>> > might be in order. That brings me to my 2a) idea, which is a
>> > datatype that only supports these operations, and none other
>> >   1) make me a new one
>> >   2) copy
>> >   3) test two such values for equality
>> >
>> > [this idea is not original with me.]
>> >
>>
>> Right now I'm digging around in PostgreSQL, so I relate everything to
>> that. They allow type extensions, and have some built-in types, including
>> various surrogate ID types, that behave as you describe.

Yes, the OIDs. The following command:

update zdd.column_deps set oid = 23 where oid = 6669823

yields this result:

ERROR: cannot assign to system column "oid"

Off on a tangent, they also have this nifty:

CREATE SEQUENCE mysequence
INSERT INTO sometable (surrogate_key) values (nextval('mysequence'))

which is much more useful than an IDENTITY type because it allows for multiple sequences inside of one table, though so far I have never needed one.

>
>

>> Those who dislike surrogate keys are probably turning green at the
>> thought.

Didn't Bob Dylan say something like:

You gotta key it on somethin',
Oh, You gotta key it on somethin',
Well it may be a surrogate,
Or it may be a natural,
But you gotta key it on somethin'

-- 
Kenneth Downs
Use first initial plus last name at last name plus literal "fam.net" to
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