MS SQL Server: Import Flat File with auto-increment ID So I've downloaded a sample database. It originally didn't have an ID column so I inserted one in through Excel. Anyways, I went through DatabaseName &gt; Tasks &gt; Import Flat File and the usual process, and arrive at the modify columns below. 



My issue is, where can I specify that the ID column should be auto-incremented? And if I can't do that here, what should I do as a workaround?
You cannot alter a column to be an IDENTITY column.  

What you'll need to do is create a new column which is defined as an IDENTITY. 

Then use an update statement to update the new column from the old one (with SET IDENTITY_INSERT ON before and OFF after the update).

Once this is done, drop the old column. 

Fianlly, rename the new one to the old name.