How do I add auto_increment to a column in SQL Server 2008

Question

I am using SQL Server 2008 and a primary key of a database table I am using is not an IDENTITY column (not sure why). I need to change that.

I am in SQ

Answer 1

You can't use ALTER TABLE ... ALTER COLUMN to modify a column to have an identity property. You'll need to

• drop the primary key constraint and any foreign key constraints referencing the column in question in your table.
• add a new column with the identity property. It should have the same type (int, I presume) as the existing column.
• update the table to seed the new column with the values of the existing column.
• alter the new column to make it non-nullable.
• drop the old/existing column.
• rename the new column so that its name is the same as that of the old column.
• Recreate the primary key and foreign key references you dropped in the 1st step.

Simple! Or something.