Ruby on Rails: How do I add a not null constraint to an existing column using a migration?

Question

In my Rails (3.2) app, I have a bunch of tables in my database but I forgot to add a few not null constraints. I\'ve googled around but I can\'t find how to write a migration wh

Answer 1

1) FIRST: Add column with default value

2) THEN: Remove default value

add_column :orders, :items, :integer, null: false, default: 0
change_column :orders, :items, :integer, default: nil