Question

so my app was working fine. I created a new model and some associaitons, rendering all the old seed data in my heroku app useless. so I tried to reset it and populate it again. but I can’t even migrate my db to heroku with the heroku rake db:migrate command. I’m using SQLite, but it seems my error is related to Postgres. I don’t know what that means, if anything

Here is the error:

rake aborted!
An error has occurred, this and all later migrations canceled:

PGError: ERROR:  column "to" cannot be cast to type "pg_catalog.int4"
: ALTER TABLE "emails" ALTER COLUMN "to" TYPE integer

Tasks: TOP => db:migrate

My migration:

class ChangeDataTypeForEmailUsers < ActiveRecord::Migration
  def self.up
      change_column :emails, :to, :integer
      change_column :emails, :from, :integer
  end

  def self.down
      change_column :to, :string
      change_column :from, :string
  end
end

What is the problem? My deployed app was working fine. I added a new model and figured I should reset the deployed database. So I ran heroku pg:reset then pushed my code to heroku. then tried to migrate the db, but it doesn’t work! What have I done? I have been trying to figure this out for the last 4 hours. I can’t think straight anymore. Any help would be greatly appreciated

Answer 1

As per heroku docs here

Cause: PostgreSQL doesn’t know how to cast all the rows in that table to the specified type. Most likely it means you have an integer or a string in that column.

Solution: Inspect your records and make sure they can be converted to the new type. Sometimes it’s easier to just avoid using change_column, renaming/creating a new column instead.

I also was in this position before and i did not find a solution so i had to create a new column, postgresql seems to be sensitive when i comes to this issues. Hope it helps