instance method destroy

Destroys the records supplied and removes them from the collection. This method will always remove record from the database ignoring the :dependent option. Returns an array with the removed records.

class Person < ActiveRecord::Base
  has_many :pets
end

person.pets.size # => 3
person.pets
# => [
#       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
#       #<Pet id: 2, name: "Spook", person_id: 1>,
#       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
#    ]

person.pets.destroy(Pet.find(1))
# => [#<Pet id: 1, name: "Fancy-Fancy", person_id: 1>]

person.pets.size # => 2
person.pets
# => [
#       #<Pet id: 2, name: "Spook", person_id: 1>,
#       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
#    ]

person.pets.destroy(Pet.find(2), Pet.find(3))
# => [
#       #<Pet id: 2, name: "Spook", person_id: 1>,
#       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
#    ]

person.pets.size  # => 0
person.pets       # => []

Pet.find(1, 2, 3) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with IDs (1, 2, 3)

You can pass Fixnum or String values, it finds the records responding to the id and then deletes them from the database.

person.pets.size # => 3
person.pets
# => [
#       #<Pet id: 4, name: "Benny", person_id: 1>,
#       #<Pet id: 5, name: "Brain", person_id: 1>,
#       #<Pet id: 6, name: "Boss",  person_id: 1>
#    ]

person.pets.destroy("4")
# => #<Pet id: 4, name: "Benny", person_id: 1>

person.pets.size # => 2
person.pets
# => [
#       #<Pet id: 5, name: "Brain", person_id: 1>,
#       #<Pet id: 6, name: "Boss",  person_id: 1>
#    ]

person.pets.destroy(5, 6)
# => [
#       #<Pet id: 5, name: "Brain", person_id: 1>,
#       #<Pet id: 6, name: "Boss",  person_id: 1>
#    ]

person.pets.size  # => 0
person.pets       # => []

Pet.find(4, 5, 6) # => ActiveRecord::RecordNotFound: Couldn't find all Pets with IDs (4, 5, 6)