From 0403efa4c6ad926a61dd0d134d63d962238e2c4f Mon Sep 17 00:00:00 2001
From: Aaron Patterson <aaron.patterson@gmail.com>
Date: Wed, 18 Aug 2010 11:32:44 -0700
Subject: delete manager added

---
 lib/arel/crud.rb                   |  7 +++++++
 lib/arel/delete_manager.rb         | 22 ++++++++++++++++++++++
 lib/arel/nodes.rb                  |  1 +
 lib/arel/nodes/delete_statement.rb | 12 ++++++++++++
 lib/arel/visitors/to_sql.rb        |  7 +++++++
 5 files changed, 49 insertions(+)
 create mode 100644 lib/arel/delete_manager.rb
 create mode 100644 lib/arel/nodes/delete_statement.rb

(limited to 'lib/arel')

diff --git a/lib/arel/crud.rb b/lib/arel/crud.rb
index 7f78acef84..6861ff016c 100644
--- a/lib/arel/crud.rb
+++ b/lib/arel/crud.rb
@@ -22,5 +22,12 @@ module Arel
       im.insert values
       @engine.connection.execute im.to_sql
     end
+
+    def delete
+      dm = DeleteManager.new @engine
+      dm.wheres = @ctx.wheres
+      dm.from @ctx.froms.last
+      @engine.connection.execute dm.to_sql
+    end
   end
 end
diff --git a/lib/arel/delete_manager.rb b/lib/arel/delete_manager.rb
new file mode 100644
index 0000000000..4759f116f1
--- /dev/null
+++ b/lib/arel/delete_manager.rb
@@ -0,0 +1,22 @@
+module Arel
+  class DeleteManager < Arel::TreeManager
+    def initialize engine
+      super
+      @head = Nodes::DeleteStatement.new
+    end
+
+    def from relation
+      @head.relation = relation
+      self
+    end
+
+    def where expression
+      @head.wheres << expression
+      self
+    end
+
+    def wheres= list
+      @head.wheres = list
+    end
+  end
+end
diff --git a/lib/arel/nodes.rb b/lib/arel/nodes.rb
index bf144ecaf8..4d6db39aec 100644
--- a/lib/arel/nodes.rb
+++ b/lib/arel/nodes.rb
@@ -8,4 +8,5 @@ require 'arel/nodes/select_core'
 require 'arel/nodes/select_statement'
 require 'arel/nodes/insert_statement'
 require 'arel/nodes/update_statement'
+require 'arel/nodes/delete_statement'
 require 'arel/nodes/unqualified_column'
diff --git a/lib/arel/nodes/delete_statement.rb b/lib/arel/nodes/delete_statement.rb
new file mode 100644
index 0000000000..54bf513c2b
--- /dev/null
+++ b/lib/arel/nodes/delete_statement.rb
@@ -0,0 +1,12 @@
+module Arel
+  module Nodes
+    class DeleteStatement
+      attr_accessor :relation, :wheres
+
+      def initialize
+        @from   = nil
+        @wheres = []
+      end
+    end
+  end
+end
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index fd467495ae..0e5998c573 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_DeleteStatement o
+        [
+          "DELETE FROM #{visit o.relation}",
+          ("WHERE #{o.wheres.map { |x| visit x }.join ' AND '}" unless o.wheres.empty?)
+        ].compact.join ' '
+      end
+
       def visit_Arel_Nodes_UpdateStatement o
         [
           "UPDATE #{visit o.relation}",
-- 
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