Uniqueidentifier datatype as like identity function???

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Uniqueidentifier datatype as like identity function???

SqlUser-529296

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September 23, 2008 at 7:41 am

#193386

Hi,
Is it possible to create a uniqueidentifier datatype column as increment by 1 as like identity function. For example, i have an int column type. In that i mentioned identity for that int datatype. So it will be display as 1,2,3,4,.....
Likewise it is possible in uniqueidentifier datatype???
For Ex,
1,25EE8EBB-DFAD-450D-BE8B-1A3F1E2568C1,'Test1'
2,25EE8EBB-DFAD-450D-BE8B-1A3F1E2568C2,'Test2'
3,25EE8EBB-DFAD-450D-BE8B-1A3F1E2568C3,'Test3'
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Viewing 8 posts - 1 through 7 (of 7 total)

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Adrian Nichols-360275 SSCertifiable Points: 7694 More actions · Answer 1

Hi,

It is certainly possible to create a GUID using NEWID() and then appending a sequential number to it; can I ask what the requirement is for this though as a GUID is supposed to be exactly that, globally unique? :crazy:

Although it's not guaranteed to be unique there are 3.4×10^38 combinations.

Ade

A Freudian Slip is when you say one thing and mean your mother.
For detail-enriched answers, ask detail-enriched questions...[/url]

Glen SSCertifiable Points: 6737 More actions · Answer 2

It is possible in SQL 2005 to create a GUID field with NEWSEQUENTIALID() default value.

NEWID() is random.

Adrian Nichols-360275 SSCertifiable Points: 7694 More actions · Answer 3

There is a privacy warning in BoL for this function

If privacy is a concern, do not use this function. It is possible to guess the value of the next generated GUID, and therefore access data associated with that GUID.

Ade

A Freudian Slip is when you say one thing and mean your mother.
For detail-enriched answers, ask detail-enriched questions...[/url]

Glen SSCertifiable Points: 6737 More actions · Answer 4

There is a privacy warning in BoL for this function

I am wondering that there is no privacy warning in BOL about identity... If with GUID I can only "quess" the next value, with identity I can predict it... 🙂

GUID are identifiers. If privacy is a concern do not return GUID back to the client application.

Adrian Nichols-360275 SSCertifiable Points: 7694 More actions · Answer 5

Glen (9/23/2008)
I am wondering that there is no privacy warning in BOL about identity...

It's not about identity, it's specifically about NEWSEQUENTIALID().

http://msdn.microsoft.com/en-us/library/ms189786(SQL.90).aspx

Ade

A Freudian Slip is when you say one thing and mean your mother.
For detail-enriched answers, ask detail-enriched questions...[/url]

SqlUser-529296 SSCarpal Tunnel Points: 4072 More actions · Answer 6

Hi Guys,

Thanks you for your valuable reply's. Because of Performance Issue, i am think about this. So that it will be in sequence when i am inserting or updating a row again in the same table. Obviously i agree still we have to change our Procedure against this Performance Issues. But this also one criteria which we need to lookup. Please get back to me if my thinking goes wrong.

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Glen SSCertifiable Points: 6737 More actions · Answer 7

Obviously i agree still we have to change our Procedure against this Performance Issues

Sorry, your original question didn't state anything about performance issues.

I am using uniqueidentifiers (GUID) with newsequentialid default values on my tables and do not see "performance issues"...