Using: Ruby 1.9.2, Rails 3.0.9, SQLite3
I am seeing some odd behavior when saving an integer field in activerecord. I have setup a test scenario in the Rails console using the following migration and corresponding model:
class CreateMyobjs < ActiveRecord::Migration def self.up create_table :myobjs do |t| t.integer :int, :default => 0, :null => false
t.timestamps end end
def self.down drop_table :myobjs end end
In the Rails console (line numbers added by me):
1 ruby-1.9.2-p290 :001 > o = Myobj.new 2 => #<Myobj id: nil, int: 0, created_at: nil, updated_at: nil> 3 ruby-1.9.2-p290 :002 > o.save 4 => true 5 ruby-1.9.2-p290 :003 > o 6 => #<Myobj id: 1, int: 0, created_at: "2011-10-12 19:59:17", updated_at: "2011-10-12 19:59:17"> 7 ruby-1.9.2-p290 :004 > o.int = '' 8 => "" 9 ruby-1.9.2-p290 :005 > o 10 => #<Myobj id: 1, int: nil, created_at: "2011-10-12 19:59:17", updated_at: "2011-10-12 19:59:17"> 11 ruby-1.9.2-p290 :006 > o.save 12 => true 13 ruby-1.9.2-p290 :007 > o 14 => #<Myobj id: 1, int: nil, created_at: "2011-10-12 19:59:17", updated_at: "2011-10-12 19:59:17"> 15 ruby-1.9.2-p290 :008 > o2 = Myobj.find(1) 16 => #<Myobj id: 1, int: 0, created_at: "2011-10-12 19:59:17", updated_at: "2011-10-12 19:59:17">
In lines 1-6 I create a new Myobj, save it and verify its attributes, at this point o.int = 0, the default value from the database.
In lines 7-10 I set the value of o.int to '' (blank string), which activerecord translates to nil, since it is an integer field.
Lines 11-12 successfully saves o with o.int set to nil, this save *should* raise an InvalidStatement exception from the database, but it does not!
Lines 13-14 verify's that the apparently saved o object still thinks the int field is nil.
Line 15-16 lookups up the record from the database and shows that the int field is not actually nil, but rather is still 0. It is apparent that the original o object did not save the int attribute properly to the database.
Trying to do the same thing when o.int starts ut as non-zero results in the following:
17 ruby-1.9.2-p290 :009 > o.int = 3 18 => 3 19 ruby-1.9.2-p290 :010 > o.save 20 => true 21 ruby-1.9.2-p290 :011 > o 22 => #<Myobj id: 1, int: 3, created_at: "2011-10-12 19:59:17", updated_at: "2011-10-12 20:08:00"> 23 ruby-1.9.2-p290 :012 > o.int = nil 24 => nil 25 ruby-1.9.2-p290 :013 > o.save 26 ActiveRecord::StatementInvalid: SQLite3::ConstraintException: myobjs.int may not be NULL: UPDATE "myobjs" SET "int" = NULL, "updated_at" = '2011-10-12 20:08:13.550661' WHERE "myobjs"."id" = 1 ...
I wont give a step-by-step description of this one, but as you can see the expected database exception is raised.
From these tests it appears that activerecord's save method is not updating integer fields when they change from 0 to nil. I think it is likely that this is because it is internally coercing the value of the integer field using to_i, and of course nil.to_i == 0.
Can anyone else confirm this behavior or think of a good reason why it would be like this?
Thanks, Chris