Add Relation#find_by and Relation#find_by!

2 files changed, 20 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb
index 0e6fecbc4b..95565b503a 100644
--- a/activerecord/lib/active_record/querying.rb
+++ b/activerecord/lib/active_record/querying.rb
@@ -5,6 +5,7 @@ module ActiveRecord
   module Querying
     delegate :find, :first, :first!, :last, :last!, :all, :exists?, :any?, :many?, :to => :scoped
     delegate :first_or_create, :first_or_create!, :first_or_initialize, :to => :scoped
+    delegate :find_by, :find_by!, :to => :scoped
     delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, :to => :scoped
     delegate :find_each, :find_in_batches, :to => :scoped
     delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins,
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 2c74f4011d..74f8e30404 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -109,6 +109,25 @@ module ActiveRecord
       end
     end
 
+    # Finds the first record matching the specified conditions. There
+    # is no implied ording so if order matters, you should specify it
+    # yourself.
+    #
+    # If no record is found, returns <tt>nil</tt>.
+    #
+    #   Post.find_by name: 'Spartacus', rating: 4
+    #   Post.find_by "published_at < ?", 2.weeks.ago
+    #
+    def find_by(*args)
+      where(*args).first
+    end
+
+    # Like <tt>find_by</tt>, except that if no record is found, raises
+    # an <tt>ActiveRecord::RecordNotFound</tt> error.
+    def find_by!(*args)
+      where(*args).first!
+    end
+
     # A convenience wrapper for <tt>find(:first, *args)</tt>. You can pass in all the
     # same arguments to this method as you can to <tt>find(:first)</tt>.
     def first(*args)