Rails - Sep 2006 - How to avoid AR confusing way of handling default values for attributes w/ :null => false

How can I avoid AR confusing way of handling default values for
attributes w/ :null => false?

This issue came up before, but I could not find an answer that resolves
the issue, which I outline below:

First, I add a test table using migrations:

class AddTestTable < ActiveRecord::Migration
  def self.up
    create_table "users", :force => true do |t|
      t.column "email", :string, :null => false
      t.column "age", :integer, :null => false
    end
  end

  def self.down
    drop_table "users"
  end
end

$ script/generate model User

$ script/console

Loading development environment.
>> User.new.email
=> ""
>> User.new.age
=> 0
I just dont understand why it defaults email to "" and age to 0 and
not
to nil. Nowhere did
I set the default email value to "" and the default age value to 0 in
my migration.

Now if I do $rake db:schema:dump here''s what the generated schema looks
like:

ActiveRecord::Schema.define(:version => 1) do

  create_table "users", :force => true do |t|
    t.column "email", :string, :default => "", :null
=> false
    t.column "age", :integer, :default => 0, :null => false
  end

end

All of a sudden there is a :default=>"" for email and a default 0
for
age

The new user would validate fine even if I set validates_presence_of
:email, :age in the model file. It even gets worst if one sets a
foreign key to :null => false, as it would default to 0!

Is there a way of overriding this confusing way that AR has to handle
default values???

Thanx,

Edoardo "Dado" Marcora


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Dear Dado:

Here is the migration script you might be looking for!  I created a new 
app, created a user model, used the following migration, did the rake 
migrate, then when I typed User.new.email, I got a nil instead of the
""
you were getting.

class CreateUsers < ActiveRecord::Migration
  def self.up
    create_table :users do |t|
      t.column "email", :string, :null => false, :default => nil
      t.column "age", :integer, :null => false, :default => nil
    end
  end

  def self.down
    drop_table :users
  end
end

I guess there are some people that think nil is a reasonable starting 
value, and others that believe the default should be initialized to a 
value within the range of allowable inputs.... I guess there will always 
be needs to do it either way...

Hope this helps!

Dominique

Dado wrote:
> How can I avoid AR confusing way of handling default values for
> attributes w/ :null => false?
> 
...
> 
> Is there a way of overriding this confusing way that AR has to handle
> default values???
> 
> Thanx,
> 
> Edoardo "Dado" Marcora

-- 
Posted via http://www.ruby-forum.com/.

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Thank you soooo much!

Dado


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Hi Dominique,

you strategy makes a lot of sense, but I tried it w/ the latest rails
and it still overrides my defaults (even when set to nil) and I am
still getting User.new.email to be "" and User.new.age to be 0... I
don''t remember AR behaving this way in the past. Any help?

Dado

Dominique Plante wrote:
> Dear Dado:
>
> Here is the migration script you might be looking for!  I created a new
> app, created a user model, used the following migration, did the rake
> migrate, then when I typed User.new.email, I got a nil instead of the
""
> you were getting.
>
> class CreateUsers < ActiveRecord::Migration
>   def self.up
>     create_table :users do |t|
>       t.column "email", :string, :null => false, :default
=> nil
>       t.column "age", :integer, :null => false, :default =>
nil
>     end
>   end
>
>   def self.down
>     drop_table :users
>   end
> end
>
> I guess there are some people that think nil is a reasonable starting
> value, and others that believe the default should be initialized to a
> value within the range of allowable inputs.... I guess there will always
> be needs to do it either way...
>
> Hope this helps!
>
> Dominique
>
> Dado wrote:
> > How can I avoid AR confusing way of handling default values for
> > attributes w/ :null => false?
> >
> ...
> >
> > Is there a way of overriding this confusing way that AR has to handle
> > default values???
> >
> > Thanx,
> >
> > Edoardo "Dado" Marcora
> 
> 
> -- 
> Posted via http://www.ruby-forum.com/.

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