Methods - transactions management
      When a connection has been opened and no transaction has been started, then the provider should execute queries in
      auto commit mode.
    
	This method starts a new transaction.
      
 
	This method commits the current transaction.
      
 
	This method cancels the current transaction.
      
 
	This method adds a save point to the current transaction, which allows for partial rollbacks within transactions.
      
 
	This method rolls back to a previously defined save point within the current transaction.
      
 
	This method deletes a previously defined save point within the current transaction, it does not affect the
	transaction but it simply won't be possible to roll back to the savepoint afterwards.