Delegate exists? to Relation

2 files changed, 34 insertions, 38 deletions

diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 5141f0b32f..2629abe778 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -556,7 +556,7 @@ module ActiveRecord #:nodoc:
       end
       alias :colorize_logging= :colorize_logging
 
-      delegate :find, :first, :last, :all, :destroy_all, :to => :scoped
+      delegate :find, :first, :last, :all, :destroy_all, :exists?, :to => :scoped
       delegate :select, :group, :order, :limit, :joins, :where, :preload, :eager_load, :includes, :from, :lock, :readonly, :having, :to => :scoped
       delegate :count, :average, :minimum, :maximum, :sum, :calculate, :to => :scoped
 
@@ -586,40 +586,6 @@ module ActiveRecord #:nodoc:
         connection.select_all(sanitize_sql(sql), "#{name} Load").collect! { |record| instantiate(record) }
       end
 
-      # Returns true if a record exists in the table that matches the +id+ or
-      # conditions given, or false otherwise. The argument can take five forms:
-      #
-      # * Integer - Finds the record with this primary key.
-      # * String - Finds the record with a primary key corresponding to this
-      #   string (such as <tt>'5'</tt>).
-      # * Array - Finds the record that matches these +find+-style conditions
-      #   (such as <tt>['color = ?', 'red']</tt>).
-      # * Hash - Finds the record that matches these +find+-style conditions
-      #   (such as <tt>{:color => 'red'}</tt>).
-      # * No args - Returns false if the table is empty, true otherwise.
-      #
-      # For more information about specifying conditions as a Hash or Array,
-      # see the Conditions section in the introduction to ActiveRecord::Base.
-      #
-      # Note: You can't pass in a condition as a string (like <tt>name =
-      # 'Jamie'</tt>), since it would be sanitized and then queried against
-      # the primary key column, like <tt>id = 'name = \'Jamie\''</tt>.
-      #
-      # ==== Examples
-      #   Person.exists?(5)
-      #   Person.exists?('5')
-      #   Person.exists?(:name => "David")
-      #   Person.exists?(['name LIKE ?', "%#{query}%"])
-      #   Person.exists?
-      def exists?(id_or_conditions = nil)
-        case id_or_conditions
-        when Array, Hash
-          where(id_or_conditions).exists?
-        else
-          scoped.exists?(id_or_conditions)
-        end
-      end
-
       # Creates an object (or multiple objects) and saves it to the database, if validations pass.
       # The resulting object is returned whether the object was saved successfully to the database or not.
       #
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 999309d2bd..2e451e380b 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -119,10 +119,40 @@ module ActiveRecord
       args.any? ? apply_finder_options(args.first).to_a : to_a
     end
 
+    # Returns true if a record exists in the table that matches the +id+ or
+    # conditions given, or false otherwise. The argument can take five forms:
+    #
+    # * Integer - Finds the record with this primary key.
+    # * String - Finds the record with a primary key corresponding to this
+    #   string (such as <tt>'5'</tt>).
+    # * Array - Finds the record that matches these +find+-style conditions
+    #   (such as <tt>['color = ?', 'red']</tt>).
+    # * Hash - Finds the record that matches these +find+-style conditions
+    #   (such as <tt>{:color => 'red'}</tt>).
+    # * No args - Returns false if the table is empty, true otherwise.
+    #
+    # For more information about specifying conditions as a Hash or Array,
+    # see the Conditions section in the introduction to ActiveRecord::Base.
+    #
+    # Note: You can't pass in a condition as a string (like <tt>name =
+    # 'Jamie'</tt>), since it would be sanitized and then queried against
+    # the primary key column, like <tt>id = 'name = \'Jamie\''</tt>.
+    #
+    # ==== Examples
+    #   Person.exists?(5)
+    #   Person.exists?('5')
+    #   Person.exists?(:name => "David")
+    #   Person.exists?(['name LIKE ?', "%#{query}%"])
+    #   Person.exists?
     def exists?(id = nil)
-      relation = select(primary_key).limit(1)
-      relation = relation.where(primary_key.eq(id)) if id
-      relation.first ? true : false
+      case id
+      when Array, Hash
+        where(id).exists?
+      else
+        relation = select(primary_key).limit(1)
+        relation = relation.where(primary_key.eq(id)) if id
+        relation.first ? true : false
+      end
     end
 
     protected