I'm not against surrogate keys. All of my data models have them. They are
necessary when there are no attributes or combination of attributes to
uniquely identify a entity occurrence. I also have implemented surrogate
keys as a performance tuning measure on large compound primary keys. The
problems come in when you make all the primary keys non-intelligent
(surrogate). This essentially removes the data integrity of the database.
I've seen many cases where the data in the database was corrupted while the
referential integrity of the tables was still fine. This situation happens
most often when the referential integrity of the database is turned off, or
the tables all have non-identifying relationships (surrogate keys). This
allows for application logic errors to be persisted with no objection from
the database. I've yet to encounter a database built totally on surrogate
keys that does not have data integrity issues. That's not to say they
don't exist, It's just that I haven't seen them and as a result, cannot
recommend it as good design.
Regards,
Walter Howard
Data Analyst
`Give your evidence,' said the King; `and don't be nervous, or I'll have
you executed on the spot.' - Alice in Wonderland
"Angay, Huseyin"
<Huseyin.Angay@egg. To: [EMAIL PROTECTED]
com> cc:
Sent by: Subject: RE: (ROSE) Transforming
Object Model to Data Model (Oracle)
owner-rose_forum@Ra
tional.com
03/20/2002 09:58 AM
Please respond to
"Angay, Huseyin"
Is there a particular reason for not liking the approach, Walter?
Most of the techniques described in the paper are pretty much the
established methods for dealing with persistence. What do the data folks
have against it?
Regards,
H�seyin Angay
Karabash Ltd.
www.karabash.co.uk
> -----Original Message-----
> From: [EMAIL PROTECTED] [SMTP:[EMAIL PROTECTED]]
> Sent: 18 March 2002 15:24
> To: [EMAIL PROTECTED]
> Subject: Re: (ROSE) Transforming Object Model to Data Model (Oracle)
>
>
>
> BTW, most data folks don't like Scott's approach.
>
> Regards,
> Walter Howard
> Data Analyst
> 972-465-4297
>
> `Give your evidence,' said the King; `and don't be nervous, or I'll have
> you executed on the spot.' - Alice in Wonderland
>
>
>
>
> PaulOldfield1@compu
>
> serve.com To:
>
> Sent by: cc: "Barrett, Kathy
> (PLC, IT, Lambert Technical Services)"
> owner-rose_forum@ra
> <[EMAIL PROTECTED]>, "'[EMAIL PROTECTED]'"
> tional.com <[EMAIL PROTECTED]>
>
> Subject: Re: (ROSE)
> Transforming Object Model to Data Model (Oracle)
>
>
> 03/15/2002 04:00 AM
>
> Please respond to
>
> PaulOldfield1
>
>
>
>
>
>
>
>
>
>
> (responding to Kathy Barrett)
>
> > I am trying to understand how relationships are transformed
> > from the Object Model to the Data Model (using an Oracle
> > database). My experience is in the relational world, and I'm
> > new to Object, so please excuse my use of terminology.
>
> Addendum - there's a good document from Scott Ambler on the
> topic at
>
> http://www.AmbySoft.com/mappingObjects.pdf
>
> If you're already up on one side (Relational in your case, most
> readers are up on the Object model) this should be a good
> place to ramp up your knowledge.
>
> HTH,
>
> Paul Oldfield
>
> any opinions expressed herein are not necessarily those of
> Mentors of Cally
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