Rails - Dec 2005 - Null Text Fields

I tend to allow nulls in cases where the value is unknown, even if
it''s a text/varchar field.  RoR seems to push empty strings into these
fields.  Is there any way to get RoR to use NULL vice '''' if
the input
box is empty?

Thanks!

- Ian

Ian Harding wrote:
> I tend to allow nulls in cases where the value is unknown, even if
> it''s a text/varchar field.  RoR seems to push empty strings into
these
> fields.  Is there any way to get RoR to use NULL vice ''''
if the input
> box is empty?
> 
> Thanks!
> 
> - Ian
I just found this problem myself.  The workaround I developed was to put 
the following into the model object you want this to work for:

  before_validation :set_empty_to_nil

  def set_empty_to_nil
    self.attributes.each {|key, value|
      if value.instance_of?(String) and value == ''''
        self["#{key}"] = nil
      end
    }
  end

Basically, everytime a create or update is performed, it walks through 
all the attributes, and if its type is "String" and is thus empty, I
set
it to nil.  (As I write this, I suppose I could have done "... 
value.empty?", but anyhoo ...)

Of course, this means you have to put it into _every_ model object you 
want this behavior for, so it sort of defeats the DRY principle.  There 
may be a better solution (callback object?) other than modifying 
ActiveRecord, but I''m not sure what that would be.  I also
haven''t
looked to see if this was filed as a bug or not.

Of course, part of the reason I did this as part of
"before_validation"
rather than "before_save" was because I wanted to use a 
"validates_uniqueness_of" and not have two empty strings declared
equal.
But as it turns out, ActiveRecord won''t allow two NULLs in a database
as
it considers NULL = NULL (even though it specifically performs an "... 
IS NULL" search).  So it was a bit of a moot point.

I can also see where a person may want '''' saved to the
database rather
than a NULL.  I''d just like the option of turning off that behavior.

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

Coey Minear wrote:
     before_validation :set_empty_to_nil

  def set_empty_to_nil
    self.attributes.each {|key, value|
      if value.instance_of?(String) and value == ''''
        self["#{key}"] = nil
      end
    }
  end

Of course, this means you have to put it into _every_ model object you 
want this behavior for, so it sort of defeats the DRY principle.  There 
may be a better solution (callback object?) other than modifying 
ActiveRecord, but I''m not sure what that would be.  Put this in a
module and mix in to each model you want the behavior for.
 
      I also haven''t 
looked to see if this was filed as a bug or not.  This seems like things working
as advertised to me, not a bug.
 If you have a form with fields left empty, those fields will still post,
they''re just empty.
 And "" != nil in ruby -- the first is a String object, the second is
nil.
 
 So it''s doing exactly what you told it to.
 
 -phil