Saturday, March 29, 2008

To Get The Current Identity Value From A Table

Let's first create our two simple tables
CREATE TABLE TestOne (id INT identity,SomeDate DATETIME)
CREATE TABLE TestTwo (id INT identity,TestOneID INT,SomeDate DATETIME)

--Let's insert 4 rows into the table
INSERT TestOne VALUES(GETDATE())
INSERT TestOne VALUES(GETDATE())
INSERT TestOne VALUES(GETDATE())
INSERT TestOne VALUES(GETDATE())



Here are diffrent ways to check for the current value

--1 @@IDENTITY
SELECT @@IDENTITY
--this returns 4


--2 DBCC CHECKIDENT
DBCC CHECKIDENT (TestOne, NORESEED)
after running DBCC CHECKIDENT the message returned is
Checking identity information: current identity value '4', current column value '4'.
DBCC execution completed. If DBCC printed error messages, contact your system administrator.


--3 MAX function
SELECT MAX(id)
FROM TestOne
you can also check with the MAX function but this is not recommended becuase you might get some other identity value that is not yours but from a different user

--4 TOP 1 and ORDER BY DESC
SELECT TOP 1 id
FROM TestOne
ORDER BY id DESC
--The same applies here as for the max function, this is not recommended


--5 IDENT_CURRENT
SELECT IDENT_CURRENT('TestOne')
--IDENT_CURRENT is another way to check


--6 SCOPE_IDENTITY
SELECT SCOPE_IDENTITY()
--This one is very similar to @@IDENTITY with one BIG difference (shown later)

3 comments:

Sudhir DBAKings said...

Nice post very helpful

dbakings

lee woo said...

In the social jungle of human existence, there is no feeling of being alive without a sense of identity. See the link below for more info.

#identity
www.ufgop.org

sarah lee said...

I really enjoyed reading your article. I found this as an informative and interesting post, so i think it is very useful and knowledgeable. I would like to thank you for the effort you have made in writing this article.


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