How do I create a rails migration to remove/change precision and scale on decimal?

Question

I am trying to remove the precision and scale attributes from decimal (PostgreSQL NUMERIC) fields in my database?

The fields:

t.decimal  "revenue_per_transaction", :precision => 8, :scale => 2 t.decimal  "item_quantity",           :precision => 8, :scale => 2 t.decimal  "goal_conversion",         :precision => 8, :scale => 2 t.decimal  "goal_abandon",            :precision => 8, :scale => 2 t.decimal  "revenue",                 :precision => 8, :scale => 2 

What do I need to add to my migration to change these to unbounded scale and precision, or to increase the scale? At the moment I'm hitting the scale limit and getting errors like:

ERROR:   numeric field overflow 

Here's the context: "PG::Error - numeric field overflow" on Heroku

Answer 1

format :

change_column(table_name, column_name, type, options): Changes the column to a different type using the same parameters as add_column. 

First in you terminal:

rails g migration change_numeric_field_in_my_table 

Then in your migration file:

class ChangeNumbericFieldInMyTable < ActiveRecord::Migration   def self.up    change_column :my_table, :revenue_per_transaction, :decimal, :precision => give whatever, :scale => give whatever   end end 

then

run rake db:migrate 

Source : http://api.rubyonrails.org/classes/ActiveRecord/Migration.html