Execute this code and you will get duplicate values in Identity values--

CREATE TABLE IdentTest

( Ident INT NOT NULL IDENTITY (1,1)

, varfield varchar(100)

)

INSERT INTO IdentTest VALUES ('xyz') -- <== Added to original

INSERT INTO IdentTest VALUES ('123') -- <== Added to original

SELECT Ident FROM IdentTest

-- Result 1,2

DBCC CHECKIDENT ('IdentTest',RESEED,100)

--Checking identity information: current identity value '2', current column value '100'.

INSERT INTO IdentTest VALUES ('abc')

SELECT Ident FROM IdentTest

--Result 1,2,101

DBCC CHECKIDENT ('IdentTest',RESEED,100)

--Checking identity information: current identity value '101', current column value '100'.

INSERT INTO IdentTest VALUES ('abc')

SELECT Ident FROM IdentTest

--Result 1,2,101,101

Its intresting to know that functionality of identity is exploiting in this way