Use ARel in SQL generation through associations

activerecord/lib/active_record/base.rb

@@ -839,26 +839,44 @@ def destroy(id)
       #   # Update all books that match our conditions, but limit it to 5 ordered by date
       #   Book.update_all "author = 'David'", "title LIKE '%Rails%'", :order => 'created_at', :limit => 5
       def update_all(updates, conditions = nil, options = {})
-        sql  = "UPDATE #{quoted_table_name} SET #{sanitize_sql_for_assignment(updates)} "
+        # sql  = "UPDATE #{quoted_table_name} SET #{sanitize_sql_for_assignment(updates)} "
 
-        scope = scope(:find)
+        # scope = scope(:find)
+
+        # select_sql = ""
+        # add_conditions!(select_sql, conditions, scope)
+
+        # if options.has_key?(:limit) || (scope && scope[:limit])
+        #   # Only take order from scope if limit is also provided by scope, this
+        #   # is useful for updating a has_many association with a limit.
+        #   add_order!(select_sql, options[:order], scope)
 
-        select_sql = ""
-        add_conditions!(select_sql, conditions, scope)
+        #   add_limit!(select_sql, options, scope)
+        #   sql.concat(connection.limited_update_conditions(select_sql, quoted_table_name, connection.quote_column_name(primary_key)))
+        # else
+        #   add_order!(select_sql, options[:order], nil)
+        #   sql.concat(select_sql)
+        # end
+
+        # connection.update(sql, "#{name} Update")
+        scope = scope(:find)
 
+        arel = arel_table
+        arel = arel.where(Arel::SqlLiteral.new(construct_conditions(conditions, scope))) if conditions || scope
         if options.has_key?(:limit) || (scope && scope[:limit])
           # Only take order from scope if limit is also provided by scope, this
           # is useful for updating a has_many association with a limit.
-          add_order!(select_sql, options[:order], scope)
+          arel = arel.order(construct_order(options[:order], scope))
 
-          add_limit!(select_sql, options, scope)
-          sql.concat(connection.limited_update_conditions(select_sql, quoted_table_name, connection.quote_column_name(primary_key)))
+          arel = arel.take(construct_limit(options, scope))
+          #arel = arel.where(connection.limited_update_conditions(select_sql, quoted_table_name, connection.quote_column_name(primary_key)))
+          #sql.concat(connection.limited_update_conditions(select_sql, quoted_table_name, connection.quote_column_name(primary_key)))
         else
-          add_order!(select_sql, options[:order], nil)
-          sql.concat(select_sql)
+          arel = arel.order(construct_order(options[:order], nil))
+          #sql.concat(select_sql)
         end
 
-        connection.update(sql, "#{name} Update")
+        arel.update(sanitize_sql_for_assignment(updates))
       end
 
       # Destroys the records matching +conditions+ by instantiating each