ruby on rails relationship between tables, multiple fields in one table related to another table

I have 2 tables: person and batch

A batch has 3 fields which relates to the person table: supervisor, creator and modifier.

All 3 fields store the person_id of the Person table.

I already created the fol开发者_运维技巧lowing relationship between the person and batch models.

class Batch < ActiveRecord::Base
    belongs_to :person, :foreign_key => "supervisor_id"
end

class Person < ActiveRecord::Base
    has_many :batches, :foreign_key => "supervisor_id"
end

So if i do 'batch.person.PER_NAME', i will get the supervisor's name..but how do i go on to get the creator and modifier details?

Many thanks for any suggestion provided

It sounds like you want 3 different relationships:

class Batch < ActiveRecord::Base
  belongs_to :supervisor
  belongs_to :creator
  belongs_to :modifier
end

Then you can reference each one independently as: batch.supervisor batch.creator batch.modifier

Alternatively, you could create a join table between the two and arbitrarily add and remove linkages:

class Batch < ActiveRecord::Base
  has_many :person_batches
  has_many :people, :through => :person_batches, :source => :persons # something like that
end

class Person < ActiveRecord::Base
  has_many :batches, :through => :person_batches
end

class PersonBatches < ActiveRecord::Base
  belongs_to :person
  belongs_to :batch

  # Has a column called :person_type where you can specify
  # "supervisor," "creator," "modifier," etc. This would
  # also allow a batch to have multiples of each, if that's
  # useful. Otherwise, you can add validations around this.
end