How do I add the identity property to an existing column in SQL Server

sql-server tsql identity
Tristan Havelick picture Tristan Havelick · Nov 13, 2008 · Viewed 73.5k times · Source

In SQL Server (in my case, 2005) how can I add the identity property to an existing table column using T-SQL?

Something like:

alter table tblFoo 
    alter column bar identity(1,1)

Answer

JohnFx picture JohnFx · Nov 13, 2008

I don't beleive you can do that. Your best bet is to create a new identity column and copy the data over using an identity insert command (if you indeed want to keep the old values).

Here is a decent article describing the process in detail: http://www.mssqltips.com/tip.asp?tip=1397

Related questions

How to change identity column values programmatically?

I have a MS SQL 2005 database with a table Test with column ID. ID is an identity column. I have rows in this table and all of them have their corresponding ID auto incremented value. Now I would like to …

Read More
Handling identity columns in an "Insert Into TABLE Values()" statement?

In SQL Server 2000 or above is there anyway to handle an auto generated primary key (identity) column when using a statement like the following? Insert Into TableName Values(?, ?, ?) My goal is to NOT use the column names at all.

Read More
@@IDENTITY, SCOPE_IDENTITY(), OUTPUT and other methods of retrieving last identity

I have seen various methods used when retrieving the value of a primary key identity field after insert. declare @t table ( id int identity primary key, somecol datetime default getdate() ) insert into @t default values select SCOPE_IDENTITY() --returns 1 select @@…

Read More