adding a level in has many association rails -

i have association in rails application between states , hospitals. state has many hospitals , hospital belongs 1 state. so,

class state < activerecord::base   has_many :hospitals end  class hospital < activerecord::base   belongs_to :state end 

so, have state_id column in hospitals table. now, due requirement, need add level of hierarchy in association ie. new model city. such that,a state has many cities, , city has many hospitals, so, state has many hospitals.

my models should -

class state < activerecord::base   has_many :cities   has_many :hospitals, through: :cities end  class hospital < activerecord::base   belongs_to :city end  class city < activerecord::base   has_many :hospitals   belongs_to :state end 

will such change in models work, if want run queries @state.hospitals

also, application has data populated state 1....n hospitals association using state_id column. how go add model in between , keep data sane ??

i'm new rails , appreciated. thanks.