1 error(s) on assignment of multiparameter attributes

I am trying to create a form for processing credit cards. For the credit card expiration date, I would like to leave the day field out of the form for obvious reasons. However, the following code is producing an error for me.

Any ideas?


<p><label for="email">Expiration</label><br/> <input type="hidden" id="user_card_expiration_3i" name="user[card_expiration(3i)]" value="1" /> <%= f.date_select(:card_expiration, :start_year => 2008, :use_month_numbers => false,                                     :discard_day => true, :include_blank => false) %></p>

ActiveRecord::MultiparameterAssignmentErrors in AccountController#signup_unlimited


{"user"=>{"company_name"=>"", "card_type"=>"Mastercard", "password_confirmation"=>"", "card_number"=>"", "card_expiration(1i)"=>"2008", "first_name"=>"", "card_expiration(2i)"=>"2", "last_name"=>"", "login"=>"", "password"=>"", "card_expiration(3i)"=>"1", "email"=>""}, "commit"=>"Sign up", "authenticity_token"=>"c4952d3607e216e85ca0ca4b76eb65272d1f85f7"}

How about leaving the date field out altogether? Passing in just a month and a year should do the trick.

Makes sense, i could even make it one single drop down. How would i have the default selection be this years current month tho?

I was able to get rid of the error by converting the column to a Date Type instead of a String type.