You can get the integer values for an enum from the class the enum is on:
Model.sale_infos # Pluralized version of the enum attribute name
That returns a hash like:
{ "plan_1" => 1, "plan_2" => 2 ... }
You can then use the sale_info value from an instance of the Model
class to access the integer value for that instance:
my_model = Model.find(123)
Model.sale_infos[my_model.sale_info] # Returns the integer value