rails populate field in model depending on another field -

i need order days name, have table field called day_name, select can sunday, monday, etc.

so thinking add field table (day_order) when enters sunday on day_name populates day_order 1, when enters monday in day_name, don't know how populate day_order depending on day_name.

there option, should when picks "sunday" in day_name, store 1 instead, , change again when read table. don't know how neither.

so need help, trying order array storing days in order , try make custom order, think easy (and faster) other way model. can sort easily.

pd: i'm looking @ before_save filter in model

i solved it,

finally added integer day_order field timetables table. , made presence mandatory

    validates :day_order, presence: true 

then limited in model number can added field with

    def day_order_enum         [1, 2, 3, 4, 5, 6]     end 

and next step doing before_validation method

    before_validation :set_day_order      def set_day_order         if self.day_name == "monday"             self.day_order = 1         elsif self.day_name == "tuesday"             self.day_order = 2         elsif self.day_name == "wednesday"             self.day_order = 3         elsif self.day_name == "thursday"             self.day_order = 4         elsif self.day_name == "friday"             self.day_order = 5         elsif self.day_name == "saturday"             self.day_order = 6         end     end 

finally made scope ordering days day_order field

    scope :day_asc_order, ->{ order('day_order asc') } 

and used day_asc_order when listing.

probably not best way it, works. if knows better way , want share it, thank him/her.

ps: don't need sunday it's not on list on purpose ;)