Re: Surrogate primary key plus unique constraint vs. natural primary key: data integrity?

Dana petak, 8. ožujka 2013. 20:22:33 UTC+1, korisnik Wolfgang Keller napisao je:  

> I've always been used to using exclusively natural (comosite) primary
>
> keys, to warrant data integrity. Now computer science people (I'm just
>
> an engineer) keep telling me that concerning data integrity, it would be
>
> absolutely equivalent to use a surrogate primary key together with a
>
> unique constraint on the natural key.

Hi Wolfgang,

It seems to me that you did not understand what is surrogate key. I suggest you look at the paper called "RM / T" by E. Codd and there you will find the definition of the surrogate key.

Please note that a surrogate key is the primary key. Note also that surrogate key is very bad solution. We note also that the surrogate key is used only in the binary relation, the so-called P-relations.

Vladimir Odrljin Received on Wed Mar 13 2013 - 08:46:54 CET