Inserting an invalid ActiveRecord date to a MySQL database

Question

MySQL allows the value of "0000-00-00" for date fields, however ActiveRecords treats an assignment to a Date value with that string as being nil.

I have a legacy application that relies on that exact field content for the notion of "Never", so if the customer last payment date is "0000-00-00" it acknowledges as being "Never" paid.

Is there a way I can override ActiveRecord (correct) validation for this date field and write this value to the database without getting my hands (too) dirty?

Thanks for any insight.

Answer 1

I hate answering my own questions, but after a little more research about AR code itself, I came up with this solution:

class CustomerInfo < BillingDatabase
  belongs_to :customer

  alias_method :old_read_attribute, :read_attribute

  def read_attribute(attr_name)
    if attr_name == "lastpaid" and old_read_attribute(attr_name).blank?
      "0000-00-00"
    else
      old_read_attribute(attr_name)
    end
  end
end

I will leave this question open in case someone has a better approach or want to comment on possible flaws.

Answer 2

You may find this slightly easier and it should achieve the same result without executing the method for every attribute in the model

class CustomerInfo < BillingDatabase
  belongs_to :customer

  def lastpaid
    value = read_attribute(:lastpaid)
    value.blank? ? "0000-00-00" : value
  end
end

You could of course refactor the code to call read_attribute twice and do the lastpaid method as a one-liner. It's a matter of style/minute performance differences really.

def lastpaid
  read_attribute(:lastpaid).blank? "0000-00-00" : read_attribute(:lastpaid)
end

Answer 3

You could change the default value on the database to be "0000-00-00" using a proper sql alter table alter column ...; statement.