Reversible migration for change_column_default from not having any default in Rails

Question

The Rails guides to active record migrations says that you can do

change_column_default :products, :approved, from: true, to: false

I\'ve got a

Answer 1

When you try to downgrade the data type , from value (0) to nil in this case , rails will complain this error. Because it might lose data

Another example would be going from string -> integer.

this is a really good article explain the same

UPDATE

It seems like your reverse migration calls change_column_default in command_recorder (activerecord-4.2.0/lib/active_record/migration/command_recorder.rb#76) please check if you set the nil as the default value.

UPDATE2

it turns out that, if you use change in migrations, those have to be able to reversible

but change_column is not reversible through change method. So you will have to use the old rails migration method with up and down

read this article explain the scenario