Clean up string data before saving in database as integer - ruby-on-rails-3

Question

I have an integer column called dollars in my database table and I am attempting to save values such as $1000 in the database. However, attempting to save the string $1000 with the dollar sign in an integer column will cause an automatic conversion to the integer 0.
To prevent this from happening, I tried to add a before_save callback to my clean_data method in my model to remove the dollar sign. But it seems that rails has already attempted to save the entire $1000 string in the database before clean_data is called.
I wonder if there is a better way to remove the dollar sign from the values before saving to the database as an integer?
Here's my code:
In the create action of the bids_controller.rb, doing this will allow the database to save the value $1000 from the form properly:
# Remove dollar sign
if params[:bid][:dollars][0] == "$"
params[:bid][:dollars] = params[:bid][:dollars].delete('$')
end
#bid = Bid.new(params[:bid])
#bid.save
However, if I were to remove the if-end fragment from the controller and clean the data in the Bid model, like this:
before_save :clean_data
def clean_data
puts self.dollars
self.dollars = self.dollars.delete('$')
end
I will get the value 0 for puts self.dollars before the clean_data method has a chance to remove the dollar sign.
My hypothesis is that rails has attempted to "hold" the data in the database before either clean_data or save is called, and this "hold" causes the data to be converted to 0 since the integer column isn't able to save the dollar sign.
Thank you very much for your help! :)

Answer 1

Take a look at the tr method.
"$1000".tr("$", "") # => "1000"
You should be able to do this on the string variable prior to saving it to the database.