basic updates are working

4 files changed, 40 insertions, 0 deletions

diff --git a/lib/arel/nodes.rb b/lib/arel/nodes.rb
index eed9641bbc..9dea981a06 100644
--- a/lib/arel/nodes.rb
+++ b/lib/arel/nodes.rb
@@ -3,3 +3,4 @@ require 'arel/nodes/sql_literal'
 require 'arel/nodes/select_core'
 require 'arel/nodes/select_statement'
 require 'arel/nodes/insert_statement'
+require 'arel/nodes/update_statement'
diff --git a/lib/arel/nodes/update_statement.rb b/lib/arel/nodes/update_statement.rb
new file mode 100644
index 0000000000..66996f11a3
--- /dev/null
+++ b/lib/arel/nodes/update_statement.rb
@@ -0,0 +1,12 @@
+module Arel
+  module Nodes
+    class UpdateStatement
+      attr_accessor :relation, :wheres
+
+      def initialize
+        @relation = nil
+        @wheres   = []
+      end
+    end
+  end
+end
diff --git a/lib/arel/update_manager.rb b/lib/arel/update_manager.rb
new file mode 100644
index 0000000000..3af73d2962
--- /dev/null
+++ b/lib/arel/update_manager.rb
@@ -0,0 +1,20 @@
+module Arel
+  class UpdateManager < Arel::TreeManager
+    def initialize engine
+      super
+      @head = Nodes::UpdateStatement.new
+    end
+
+    ###
+    # UPDATE +table+
+    def table table
+      @head.relation = table
+      self
+    end
+
+    def where expr
+      @head.wheres << expr
+      self
+    end
+  end
+end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index d47c621f6a..41d1299948 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -12,6 +12,13 @@ module Arel
       end
 
       private
+      def visit_Arel_Nodes_UpdateStatement o
+        [
+          "UPDATE #{visit o.relation}",
+          ("WHERE #{o.wheres.map { |x| visit x }.join ' AND '}" unless o.wheres.empty?)
+        ].compact.join ' '
+      end
+
       def visit_Arel_Nodes_InsertStatement o
         [
           "INSERT INTO #{visit o.relation}",