How do I retroactively add a primary key to my table in rails?

Question

I\'ve created a table without a primary key (:id => false), but now it has come back to bite my ass.

My app is already in production and I can\'t just drop it and recre

Answer 1

If for some reason you created a table with a custom id field, but forgot to set id as the primary key, you need to run a migration to create the primary key constraint. The following was tested against a PostgreSQL database:

class AddPrimaryKeyConstraintToFoobars < ActiveRecord::Migration
  def up
    execute "ALTER TABLE foobars ADD PRIMARY KEY (id);"
  end

  def down
    execute "ALTER TABLE foobars DROP CONSTRAINT foobars_pkey;"
  end
end