Change_column_null for an existing column

Question

I am trying to change the nil capability of a boolean attribute in an existing column :access_titles in a table :profiles . This column exists due to this migration:

 class AddAccessItemsToProfiles < ActiveRecord::Migration def self.up add_column :profiles, :access_items, :boolean, :default => true end def self.down remove_column :profiles, :access_items, :boolean, :default => nil end end 

To change nil , I tried to create a migration, as always:

 rails g migration ChangeColumnNull :profiles :access_items :null => false 

But it didn’t do anything, so I did a separate migration:

 rails g migration AddChangeColumnNullToAccessItems 

And in this I added:

 class AddChangeColumnNullToAccessItems < ActiveRecord::Migration def self.up change_column_null :profiles, :access_items, :boolean, false end def self.down change_column_null :profiles, :access_items, :boolean, true end end 

Then I ran rake db:migrate , restarted my server and did not see any changes. So I tried:

 class AddChangeColumnNullToAccessItems < ActiveRecord::Migration def self.up change_column_null :profiles, :access_items, false end def self.down change_column_null :profiles, :access_items, true end end 

Then he did the same: rake db:migrate , restarted the server and nothing changed.

What am I doing wrong? I was hoping that only the boolean value :access_items would be true and false without having to reset the database.

UPDATE: Trying change_column_null :profiles, :access_items, false I got an error:

 -- change_column_null(:profiles, :access_items, false) rake aborted! An error has occurred, this and all later migrations canceled: PGError: ERROR: column "access_items" contains null values : ALTER TABLE "profiles" ALTER "access_items" SET NOT NULL 

So, according to the advice below, I had to insert change_column_null :profiles, :access_items, false, true in my migration.

Answer 1

You can use:

 change_column_null :profiles, :access_items, false, 1 

The fourth parameter is optional and allows you to set the default value for the column. This is necessary when you have zeros in the column and you set the value to zero.