How can I add a column that doesn't allow nulls in a Postgresql database?

Question

I\'m adding a new, \"NOT NULL\" column to my Postgresql database using the following query (sanitized for the Internet):

ALTER TABLE mytable ADD COLUMN mycol         


        

Answer 1

Or, create a new table as temp with the extra column, copy the data to this new table while manipulating it as necessary to fill the non-nullable new column, and then swap the table via a two-step name change.

Yes, it is more complicated, but you may need to do it this way if you don't want a big UPDATE on a live table.