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-rw-r--r--activerecord/CHANGELOG.md4
-rw-r--r--activerecord/lib/active_record/associations/association.rb7
-rw-r--r--activerecord/lib/active_record/counter_cache.rb2
-rw-r--r--activerecord/lib/active_record/inheritance.rb7
-rw-r--r--activerecord/lib/active_record/relation/batches.rb58
-rw-r--r--activerecord/lib/active_record/relation/finder_methods.rb49
6 files changed, 96 insertions, 31 deletions
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index c428522842..ab1eb49286 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -170,8 +170,8 @@
*Olek Janiszewski*
-* fixes bug introduced by #3329. Now, when autosaving associations,
- deletions happen before inserts and saves. This prevents a 'duplicate
+* fixes bug introduced by #3329. Now, when autosaving associations,
+ deletions happen before inserts and saves. This prevents a 'duplicate
unique value' database error that would occur if a record being created had
the same value on a unique indexed field as that of a record being destroyed.
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index 608a6af16c..ee62298793 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -200,13 +200,14 @@ module ActiveRecord
creation_attributes.each { |key, value| record[key] = value }
end
- # Should be true if there is a foreign key present on the owner which
+ # Returns true if there is a foreign key present on the owner which
# references the target. This is used to determine whether we can load
# the target if the owner is currently a new record (and therefore
- # without a key).
+ # without a key). If the owner is a new record then foreign_key must
+ # be present in order to load target.
#
# Currently implemented by belongs_to (vanilla and polymorphic) and
- # has_one/has_many :through associations which go through a belongs_to
+ # has_one/has_many :through associations which go through a belongs_to.
def foreign_key_present?
false
end
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index 81cca37939..e1faadf1ab 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -50,7 +50,7 @@ module ActiveRecord
# ==== Parameters
#
# * +id+ - The id of the object you wish to update a counter on or an Array of ids.
- # * +counters+ - An Array of Hashes containing the names of the fields
+ # * +counters+ - A Hash containing the names of the fields
# to update as keys and the amount to update the field by as values.
#
# ==== Examples
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index 40976bc29e..e826762def 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -5,7 +5,7 @@ module ActiveRecord
extend ActiveSupport::Concern
included do
- # Determine whether to store the full constant name including namespace when using STI
+ # Determines whether to store the full constant name including namespace when using STI.
class_attribute :store_full_sti_class, instance_writer: false
self.store_full_sti_class = true
end
@@ -13,7 +13,7 @@ module ActiveRecord
module ClassMethods
# Determines if one of the attributes passed in is the inheritance column,
# and if the inheritance column is attr accessible, it initializes an
- # instance of the given subclass instead of the base class
+ # instance of the given subclass instead of the base class.
def new(*args, &block)
if abstract_class? || self == Base
raise NotImplementedError, "#{self} is an abstract class and can not be instantiated."
@@ -27,7 +27,8 @@ module ActiveRecord
super
end
- # True if this isn't a concrete subclass needing a STI type condition.
+ # Returns +true+ if this does not need STI type condition. Returns
+ # +false+ if STI type condition needs to be applied.
def descends_from_active_record?
if self == Base
false
diff --git a/activerecord/lib/active_record/relation/batches.rb b/activerecord/lib/active_record/relation/batches.rb
index b921f2eddb..41291844fc 100644
--- a/activerecord/lib/active_record/relation/batches.rb
+++ b/activerecord/lib/active_record/relation/batches.rb
@@ -11,7 +11,7 @@ module ActiveRecord
# The #find_each method uses #find_in_batches with a batch size of 1000 (or as
# specified by the +:batch_size+ option).
#
- # Person.all.find_each do |person|
+ # Person.find_each do |person|
# person.do_awesome_stuff
# end
#
@@ -19,8 +19,26 @@ module ActiveRecord
# person.party_all_night!
# end
#
- # You can also pass the +:start+ option to specify
- # an offset to control the starting point.
+ # ==== Options
+ # * <tt>:batch_size</tt> - Specifies the size of the batch. Default to 1000.
+ # * <tt>:start</tt> - Specifies the starting point for the batch processing.
+ # This is especially useful if you want multiple workers dealing with
+ # the same processing queue. You can make worker 1 handle all the records
+ # between id 0 and 10,000 and worker 2 handle from 10,000 and beyond
+ # (by setting the +:start+ option on that worker).
+ #
+ # # Let's process for a batch of 2000 records, skiping the first 2000 rows
+ # Person.find_each(start: 2000, batch_size: 2000) do |person|
+ # person.party_all_night!
+ # end
+ #
+ # NOTE: It's not possible to set the order. That is automatically set to
+ # ascending on the primary key ("id ASC") to make the batch ordering
+ # work. This also means that this method only works with integer-based
+ # primary keys.
+ #
+ # NOTE: You can't set the limit either, that's used to control
+ # the batch sizes.
def find_each(options = {})
find_in_batches(options) do |records|
records.each { |record| yield record }
@@ -28,31 +46,33 @@ module ActiveRecord
end
# Yields each batch of records that was found by the find +options+ as
- # an array. The size of each batch is set by the +:batch_size+
- # option; the default is 1000.
- #
- # You can control the starting point for the batch processing by
- # supplying the +:start+ option. This is especially useful if you
- # want multiple workers dealing with the same processing queue. You can
- # make worker 1 handle all the records between id 0 and 10,000 and
- # worker 2 handle from 10,000 and beyond (by setting the +:start+
- # option on that worker).
- #
- # It's not possible to set the order. That is automatically set to
- # ascending on the primary key ("id ASC") to make the batch ordering
- # work. This also means that this method only works with integer-based
- # primary keys. You can't set the limit either, that's used to control
- # the batch sizes.
+ # an array.
#
# Person.where("age > 21").find_in_batches do |group|
# sleep(50) # Make sure it doesn't get too crowded in there!
# group.each { |person| person.party_all_night! }
# end
#
+ # ==== Options
+ # * <tt>:batch_size</tt> - Specifies the size of the batch. Default to 1000.
+ # * <tt>:start</tt> - Specifies the starting point for the batch processing.
+ # This is especially useful if you want multiple workers dealing with
+ # the same processing queue. You can make worker 1 handle all the records
+ # between id 0 and 10,000 and worker 2 handle from 10,000 and beyond
+ # (by setting the +:start+ option on that worker).
+ #
# # Let's process the next 2000 records
- # Person.all.find_in_batches(start: 2000, batch_size: 2000) do |group|
+ # Person.find_in_batches(start: 2000, batch_size: 2000) do |group|
# group.each { |person| person.party_all_night! }
# end
+ #
+ # NOTE: It's not possible to set the order. That is automatically set to
+ # ascending on the primary key ("id ASC") to make the batch ordering
+ # work. This also means that this method only works with integer-based
+ # primary keys.
+ #
+ # NOTE: You can't set the limit either, that's used to control
+ # the batch sizes.
def find_in_batches(options = {})
options.assert_valid_keys(:start, :batch_size)
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index cbb2803593..1550d702a6 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -11,9 +11,11 @@ module ActiveRecord
# 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
- # provide since database rows are unordered. Give an explicit <tt>order</tt>
- # to ensure the results are sorted.
+ # <tt>ActiveRecord::RecordNotFound</tt> will be raised if one or more ids are not found.
+ #
+ # NOTE: The returned records may not be in the same order as the ids you
+ # provide since database rows are unordered. You'd need to provide an explicit <tt>order</tt>
+ # option if you want the results are sorted.
#
# ==== Find with lock
#
@@ -28,6 +30,34 @@ module ActiveRecord
# 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 a boolean indicating if any record with the given conditions exist.
+ #
+ # 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.
def find(*args)
if block_given?
to_a.find { |*block_args| yield(*block_args) }
@@ -79,6 +109,19 @@ module ActiveRecord
# Person.where(["user_name = :u", { u: user_name }]).first
# Person.order("created_on DESC").offset(5).first
# Person.first(3) # returns the first three objects fetched by SELECT * FROM people LIMIT 3
+ #
+ # ==== Rails 3
+ #
+ # Person.first # SELECT "people".* FROM "people" LIMIT 1
+ #
+ # NOTE: Rails 3 may not order this query by the primary key and the order
+ # will depend on the database implementation. In order to ensure that behavior,
+ # use <tt>User.order(:id).first</tt> instead.
+ #
+ # ==== Rails 4
+ #
+ # Person.first # SELECT "people".* FROM "people" ORDER BY "people"."id" ASC LIMIT 1
+ #
def first(limit = nil)
if limit
if order_values.empty? && primary_key