Question

I’ve added a column to a db in rails via a migration, and updated new.html.erb to add the field to the form.

The correct data is in the request params, but the insert query that is generated has a null for the column every time.

Here are the request params:

{"commit"=>"Create",
  "assignment"=>{"start_date"=>"08/04/2010",
  "project_id"=>"5",
  "allotment"=>"50",
  "person_id"=>"33",
  "end_date"=>"08/05/2010"},
  "authenticity_token"=>"8f157a2a220caf716607162ce9557ab6505aab1a"}

and here is the resulting error with query showing the null column:

Mysql::Error: Column 'end_date' cannot be null: 
INSERT INTO `assignments` (`start_date`, `created_at`, `project_id`, `updated_at`, `allotment`, `person_id`, `end_date`)
VALUES('2010-08-04', '2010-08-04 03:36:21', 5, '2010-08-04 03:36:21', 50, 33, NULL)

Here’s the migration in question:

class ChangeDates < ActiveRecord::Migration
  def self.up
    add_column :assignments, :end_date, :date, :null => false
    rename_column :assignments, :date, :start_date
  end

  def self.down
    remove_column :assignments, :end_date
    rename_column :assignments, :start_date, :date
  end
end

I can’t figure out what went wrong. I’ve rolled back and migrated the change a couple of times with no luck. I’m stumped.

Answer 1

To answer you question about attr_accessor, scope will call the accessors method before the class method, so were saving the value to the accessor, but when the save was called it was returning the method call. I hope this clarifies it by example: http://codepad.org/gAppUMc4

I’ve done the same thing several times. Its super frustrating.