Re: Database design, Keys and some other things
From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Fri, 30 Sep 2005 17:28:06 +0200
Message-ID: <433d595a$0$11068$e4fe514c_at_news.xs4all.nl>
>>Marshall Spight wrote:
>>
>>>Perhaps we have different definitions of surrogate keys. The VIN
>>>may be something that's not a surrogate key in database A, but
>>>it's certainly a surrogate key in *some* database, and hence I
>>>don't see any particular difference between it and any other
>>>made-up identifiers. SOMEone, some database, made up the VIN
>>>out of thin air; we could well say they "implemented [it] to get
>>>[their] system working." So I still don't see the distinction
>>>you're drawing here.
>>
>>There is an important difference. Unless we are talking about
>>that specific "*some*" database, the VIN is /not/ a surrogate key in
>>the database at hand.
Date: Fri, 30 Sep 2005 17:28:06 +0200
Message-ID: <433d595a$0$11068$e4fe514c_at_news.xs4all.nl>
Marshall Spight wrote:
> mAsterdam wrote:
>>Marshall Spight wrote:
>>
>>>Perhaps we have different definitions of surrogate keys. The VIN
>>>may be something that's not a surrogate key in database A, but
>>>it's certainly a surrogate key in *some* database, and hence I
>>>don't see any particular difference between it and any other
>>>made-up identifiers. SOMEone, some database, made up the VIN
>>>out of thin air; we could well say they "implemented [it] to get
>>>[their] system working." So I still don't see the distinction
>>>you're drawing here.
>>
>>There is an important difference. Unless we are talking about
>>that specific "*some*" database, the VIN is /not/ a surrogate key in
>>the database at hand.
> > So you are saying that whether something is a surrogate key > or not is determined within the context of a specific database?
Just as the key-ness of something is.
Is column x a key for table y?
The question only makes sense within the context
of a specific database.
But I may have misunderstood your question. Received on Fri Sep 30 2005 - 17:28:06 CEST