PG::DatatypeMismatch - Cant change columns data type from boolean to integer

[oliverochman]

Problem

When I try to change a columns data type from boolean to integer I get an error from postgres about how the column cant automatically be cast to the type of integer.

Background

I have a model with the name Inquiry that has a column named flexible regarding if the person needs to have a flexible office situation or not. Initially it was a true/false, but with input from the client we now need to be able to have both as an option. Therefor I created a migration to change the data type of that column from boolean to integer so I can make use of enums to solve that issue.

Implementation code

This is how the migration file looks like

class ChangeDataTypeForFlexible < ActiveRecord::Migration[6.1]
  def change
    change_column :inquiries, :flexible, :integer
  end
end

Screenshots

[oliverochman]

I don't have an explanation for why this works, I found this solution online.

class ChangeDataTypeForFlexible < ActiveRecord::Migration[6.1]
  def change
    change_column :inquiries, :flexible, 'integer USING CAST(flexible AS integer)'
  end
end

If you change your migration file to this, it will work