Identity Column Rollover

If I have an Identity column defined as a smallint
seed=1, increment=1
Does it automatically roll back to 1 when the number of records reaches
32,767. Assuming of course, the last record assigned identity 1 has been
removed.
I assume it does, but hey, I've assumed stuff like this before and gotten
burned.
JohnNo it does not automatically roll over. Instead you will receive an
overflow error and future inserts will fail. You could then reseed the
value using the DBCC CHECKIDENT command. A much better plan however, is
to create the column large enough that it won't overflow for the
forseeable future.
David Portas
SQL Server MVP
--|||No, you assume wrong. You'll get an error when you try to insert a new row.
"Arithmetic overflow error for data type smallint, value = 32768"
Change to Int if you believe that it may be a problem.
"John Manion" <JohnManion@.discussions.microsoft.com> wrote in message
news:785FF58A-2C96-4AAF-9E2A-30C918853DDE@.microsoft.com...
> If I have an Identity column defined as a smallint
> seed=1, increment=1
> Does it automatically roll back to 1 when the number of records reaches
> 32,767. Assuming of course, the last record assigned identity 1 has been
> removed.
> I assume it does, but hey, I've assumed stuff like this before and gotten
> burned.
> John|||No. SQL Server will try to increment the identity value and also give you an
error when trying to store the new value.
Example:
use northwind
go
create table t (
colA smallint not null identity
)
go
set identity_insert t on
go
insert into t (colA) values(32767)
go
set identity_insert t off
go
select * from t
go
insert into t default values
go
select * from t
go
drop table t
go
AMB
"John Manion" wrote:

> If I have an Identity column defined as a smallint
> seed=1, increment=1
> Does it automatically roll back to 1 when the number of records reaches
> 32,767. Assuming of course, the last record assigned identity 1 has been
> removed.
> I assume it does, but hey, I've assumed stuff like this before and gotten
> burned.
> John|||Not surprising.
Thanks,
John
"David Portas" wrote:

> No it does not automatically roll over. Instead you will receive an
> overflow error and future inserts will fail. You could then reseed the
> value using the DBCC CHECKIDENT command. A much better plan however, is
> to create the column large enough that it won't overflow for the
> forseeable future.
> --
> David Portas
> SQL Server MVP
> --
>