> 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.
If this is true, why wouldn't your second example also succeed? Since in both you are setting o.int to nil which should then get coerced to zero. Actually you're not doing exactly the same thing. In the former you are setting o.int to "" and in the latter setting it to nil. So it could be that Rails is calling to_i on "", but not on nil... hence the error... And "".to_i => 0 I haven't actually checked the source though, but seems like skipping type coercion on nil fields is a logical thing to do. > Can anyone else confirm this behavior or think of a good reason why it > would be like this? > > Thanks, > Chris > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/rubyonrails-talk?hl=en. > -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
