Introduced ActiveRecord::Relation, a layer between an ARel relation and an AR relation

1 files changed, 39 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
new file mode 100644
index 0000000000..36e8d98298
--- /dev/null
+++ b/activerecord/lib/active_record/relation.rb
@@ -0,0 +1,39 @@
+module ActiveRecord
+  class Relation
+    delegate :delete, :to_sql, :to => :relation
+    CLAUSES_METHODS = ["where", "join", "project", "group", "order", "take", "skip"].freeze
+    attr_reader :relation, :klass
+
+    def initialize(klass, table = nil)
+      @klass = klass
+      @relation = Arel::Table.new(table || @klass.table_name)
+    end
+
+    def to_a
+      @klass.find_by_sql(@relation.to_sql)
+    end
+
+    def first
+      @relation = @relation.take(1)
+      to_a.first
+    end
+
+    for clause in CLAUSES_METHODS
+      class_eval %{
+        def #{clause}(_#{clause})
+          @relation = @relation.#{clause}(_#{clause}) if _#{clause}
+          self
+        end
+      }
+    end
+
+    private
+      def method_missing(method, *args, &block)
+        if @relation.respond_to?(method)
+          @relation.send(method, *args, &block)
+        elsif Array.instance_methods.include?(method.to_s)
+          to_a.send(method, *args, &block)
+        end
+      end
+  end
+end