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instructions for variations and alternatives for ActiveRecord#find

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commit 667569ab04159b144d799f5fc97c3d862b2c30aa 1 parent 6de2644
@thejamespinto thejamespinto authored
Showing with 35 additions and 1 deletion.
  1. +35 −1 activerecord/lib/active_record/relation/finder_methods.rb
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36 activerecord/lib/active_record/relation/finder_methods.rb
@@ -11,7 +11,9 @@ module FinderMethods
# Person.find([1]) # returns an array for the object with ID = 1
# Person.where("administrator = 1").order("created_on DESC").find(1)
#
- # Note that returned records may not be in the same order as the ids you
+ # NOTE: An RecordNotFound will be raised if one or more ids are not returned.
+ #
+ # NOTE: that returned records may not be in the same order as the ids you
# provide since database rows are unordered. Give an explicit <tt>order</tt>
# to ensure the results are sorted.
#
@@ -28,6 +30,38 @@ module FinderMethods
# person.visits += 1
# person.save!
# end
+ #
+ # ==== Variations of +find+
+ #
+ # Person.where(name: 'Spartacus', rating: 4)
+ # # returns a chainable list (which can be empty)
+ #
+ # Person.find_by(name: 'Spartacus', rating: 4)
+ # # returns the first item or nil
+ #
+ # Person.where(name: 'Spartacus', rating: 4).first_or_initialize
+ # # returns the first item or returns a new instance (requires you call .save to persist against the database)
+ #
+ # Person.where(name: 'Spartacus', rating: 4).first_or_create
+ # # returns the first item or creates it and returns it, available since rails 3.2.1
+ #
+ #
+ # ==== Alternatives for +find+
+ #
+ # Person.where(name: 'Spartacus', rating: 4).exists?(conditions = :none)
+ # # returns true or false
+ #
+ # Person.where(name: 'Spartacus', rating: 4).select("field1, field2, field3")
+ # # returns a chainable list of instances with only the mentioned fields
+ #
+ # Person.where(name: 'Spartacus', rating: 4).ids
+ # # returns an Array of ids, available since rails 3.2.1
+ #
+ # Person.where(name: 'Spartacus', rating: 4).pluck(:field1, :field2)
+ # # returns an Array of the required fields, available since rails 3.1
+ #
+ # Person.arel_table
+ # # returns an instance of <tt>Arel::Table</tt>, which allows a comprehensive variety of filters
def find(*args)
if block_given?
to_a.find { |*block_args| yield(*block_args) }
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