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[ci skip] Fix the API docs for Bi-directional associations

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The examples now take in consideration when Active Record finds inverse
associations automatically.
This commit is contained in:
Roque Pinel 2015-06-13 09:37:55 -04:00
parent 335a2b8a40
commit 55703f94c0
1 changed files with 7 additions and 12 deletions
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19
activerecord/lib/active_record/associations.rb
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@ -955,20 +955,16 @@ module ActiveRecord
# The +traps+ association on +Dungeon+ and the +dungeon+ association on +Trap+ are
# the inverse of each other and the inverse of the +dungeon+ association on +EvilWizard+
# is the +evil_wizard+ association on +Dungeon+ (and vice-versa). By default,
# Active Record doesn't know anything about these inverse relationships and so no object
# loading optimization is possible. For example:
# Active Record can guess the inverse of the association based on the name
# of the class. The result is the following:
#
# d = Dungeon.first
# t = d.traps.first
# d.level == t.dungeon.level # => true
# d.level = 10
# d.level == t.dungeon.level # => false
# d.object_id == t.dungeon.object_id # => true
#
# The +Dungeon+ instances +d+ and <tt>t.dungeon</tt> in the above example refer to
# the same object data from the database, but are actually different in-memory copies
# of that data. Specifying the <tt>:inverse_of</tt> option on associations lets you tell
# Active Record about inverse relationships and it will optimise object loading. For
# example, if we changed our model definitions to:
# the same in-memory instance since the association matches the name of the class.
# The result would be the same if we added +:inverse_of+ to our model definitions:
#
# class Dungeon < ActiveRecord::Base
# has_many :traps, inverse_of: :dungeon
@ -983,15 +979,14 @@ module ActiveRecord
# belongs_to :dungeon, inverse_of: :evil_wizard
# end
#
# Then, from our code snippet above, +d+ and <tt>t.dungeon</tt> are actually the same
# in-memory instance and our final <tt>d.level == t.dungeon.level</tt> will return +true+.
#
# There are limitations to <tt>:inverse_of</tt> support:
#
# * does not work with <tt>:through</tt> associations.
# * does not work with <tt>:polymorphic</tt> associations.
# * for +belongs_to+ associations +has_many+ inverse associations are ignored.
#
# For more information, see the documentation for the +:inverse_of+ option.
#
# == Deleting from associations
#
# === Dependent associations