3 files changed, 83 insertions, 0 deletions
diff --git a/lib/arel/relations/writes/delete.rb b/lib/arel/relations/writes/delete.rb
new file mode 100644
index 0000000000..2eaad6d1da
--- /dev/null
+++ b/lib/arel/relations/writes/delete.rb
@@ -0,0 +1,25 @@
+module Arel
+  class Deletion < Compound
+    def initialize(relation)
+      @relation = relation
+    end
+
+    def to_sql(formatter = nil)
+      [
+        "DELETE",
+        "FROM #{table_sql}",
+        ("WHERE #{wheres.collect(&:to_sql).join('\n\tAND ')}" unless wheres.blank?  ),
+        ("LIMIT     #{taken}"                                  unless taken.blank?    ),
+      ].compact.join("\n")
+    end
+    
+    def call(connection = engine.connection)
+      connection.delete(to_sql)
+    end
+    
+    def ==(other)
+      Deletion    === other and
+      relation    ==  other.relation
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/arel/relations/writes/insert.rb b/lib/arel/relations/writes/insert.rb
new file mode 100644
index 0000000000..a1c4c93de5
--- /dev/null
+++ b/lib/arel/relations/writes/insert.rb
@@ -0,0 +1,28 @@
+module Arel
+  class Insert < Compound
+    attr_reader :record
+
+    def initialize(relation, record)
+      @relation, @record = relation, record.bind(relation)
+    end
+
+    def to_sql(formatter = nil)
+      [
+        "INSERT",
+        "INTO #{table_sql}",
+        "(#{record.keys.collect(&:to_sql).join(', ')})",
+        "VALUES (#{record.collect { |key, value| key.format(value) }.join(', ')})"
+      ].join("\n")
+    end
+    
+    def call(connection = engine.connection)
+      connection.insert(to_sql)
+    end
+    
+    def ==(other)
+      Insert   === other         and
+      relation    == other.relation and
+      record      == other.record
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/arel/relations/writes/update.rb b/lib/arel/relations/writes/update.rb
new file mode 100644
index 0000000000..760f4e931f
--- /dev/null
+++ b/lib/arel/relations/writes/update.rb
@@ -0,0 +1,30 @@
+module Arel
+  class Update < Compound
+    attr_reader :assignments
+
+    def initialize(relation, assignments)
+      @relation, @assignments = relation, assignments.bind(relation)
+    end
+
+    def to_sql(formatter = nil)
+      [
+        "UPDATE #{table_sql} SET",
+        assignments.collect do |attribute, value|
+          "#{value.format(attribute)} = #{attribute.format(value)}"
+        end.join(",\n"),
+        ("WHERE #{wheres.collect(&:to_sql).join('\n\tAND ')}"  unless wheres.blank?  ),
+        ("LIMIT     #{taken}"                                  unless taken.blank?    )
+      ].join("\n")
+    end
+    
+    def call(connection = engine.connection)
+      connection.update(to_sql)
+    end
+    
+    def ==(other)
+      Update      === other          and
+      relation    ==  other.relation and
+      assignments ==  other.assignments
+    end
+  end
+end
+\ No newline at end of file