Re: Oracle NULL vs '' revisited

From: Tony Rogerson <tonyrogerson_at_torver.net>
Date: Fri, 24 Aug 2007 20:32:05 +0100
Message-ID: <fanbpq$nei$1$8300dec7@news.demon.co.uk>

> The point was to demonstrate the surrogate keys are worthless
> for purposes of data integrity with most data. What ends up
> happening is that unique constraints are then built, on top of
> the surrogate key, in an attempt to do what the surrogate can
> not.

Oh really?

Then why say this "Natural keys can not change. If it can change IT IS NOT A KEY it is
just a value.".

You seem to be under the impression that "Natural keys can not change".

On another point, I'm STILL awaiting your email reply to why this isn't an equiv "system
trigger" in SQL Server compared to your Oracle LOGON trigger....

Link: http://technet.microsoft.com/en-us/library/ms189799.aspx

CREATE TRIGGER connection_limit_trigger
ON ALL SERVER WITH EXECUTE AS 'login_test' FOR LOGON
AS
BEGIN
IF ORIGINAL_LOGIN()= 'login_test' AND

(SELECT COUNT(*) FROM sys.dm_exec_sessions

            WHERE is_user_process = 1 AND
                original_login_name = 'login_test') > 3

ROLLBACK;
END;

-- 
Tony Rogerson, SQL Server MVP
http://sqlblogcasts.com/blogs/tonyrogerson
[Ramblings from the field from a SQL consultant]
http://sqlserverfaq.com
[UK SQL User Community]


"DA Morgan" <damorgan_at_psoug.org> wrote in message 
news:1187977798.50878_at_bubbleator.drizzle.com...


> Tony Rogerson wrote:

>>
>>> ID   FNAME     LNAME
>>> 1    Daniel    Morgan
>>> 2    Jack      Cline
>>> 3    Daniel    Morgan
>>>
>>> That surrogate key accomplished precisely what?
>>
>> And where is your natural key?
>


> The point was to demonstrate the surrogate keys are worthless

> for purposes of data integrity with most data. What ends up

> happening is that unique constraints are then built, on top of

> the surrogate key, in an attempt to do what the surrogate can

> not.

> -- 

> Daniel A. Morgan

> University of Washington

> damorgan_at_x.washington.edu (replace x with u to respond)

> Puget Sound Oracle Users Group

> www.psoug.org

Received on Fri Aug 24 2007 - 14:32:05 CDT