anchor.diff:  
   (**
       
  -*)+*)
  
positive.code: 
  <div class="well well-small" style="margin:0px 70px 0px 20px;">
  
  **TIP** Sql Server can use multiple `SQLConnections` in a `TransactionScope` without escalating, 
  provided the connections are not open at the same time, 
  which would result in multiple "physical" TCP connections and thus require escalation.
  </p></div>
  
  <div class="well well-small" style="margin:0px 70px 0px 20px;">
  
  **TIP** A value of [Enlist](https://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnectionstringbuilder.enlist.aspx) 
  key from [SqlConnection.ConnectionString](https://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectionstring.aspx) 
  property determines auto-enlistment behavior of connection instance.
  </p></div>
  
  TransactionScope + AsyncExecute 
  -------------------------------------
  
  Another tricky problem is combining `TransactionScope` with asynchronous execution. 
  `TransactoinScope` [has thread affinity](http://stackoverflow.com/q/13543254/1603572). 
  To propagate transaction context to other thread .NET 4.5.1 introduced [TransactionScopeAsyncFlowOption.Enabled](https://msdn.microsoft.com/en-us/library/system.transactions.transactionscopeasyncflowoption.aspx). 
  This setting needs to be passed into [TransactionScope constructor](https://msdn.microsoft.com/en-us/library/dn261473.aspx). 
  Unfortunately if you stuck with the .NET Framework before 4.5.1 version the only way 
  to combine `TransactionScope` with `AsyncExecute` is explicit transactions.  
  
  *)
  
negative.code: 
      tran.Complete()
  
  DataTable Updates/Bulk Load
  -------------------------------------
  Statically typed data tables generated either by SqlProgrammabilityProvider or by SqlCommandProvider 
  with ResultType.DataTable have two helper methods `Update` and `BulkCopy` to send changes back into the database. 
  Both methods accept connection and transaction to support explicit transactions.
  
  The example above which inserts a new USD/GBP currency rate can be re-written as
  *)
  
  do
  