<?xml version= "1 . 0 " encoding= "windows-1251 "?>
<ROOT>
<DS A= "1 " B= "123E-01 " />
<DS A= "2 " B= "345E-02 " />
<DS A= "3 " B= "678E-03 " />
</ROOT>

CREATE PROCEDURE [dbo].[SomeSP]
 ...
 ,  @I_XML  text
AS
   set nocount on

   declare @XMLID int
   exec sp_xml_preparedocument @XMLID out, @I_XML

   declare @tXML table(A int primary key, B double precision)
   insert into @tXML
   select A,B from openxml(@XMLID,'/ROOT/DS', 1 )
   with(A int,B double precision)

   exec sp_xml_removedocument @XMLID

   begin tran

      insert into SomeTable1 select A, B from @tXML

      update SomeTable2 set Y = B
      from SomeTable2 inner join @tXML on X = A

 . . .