Jeanne Combrinck explains the purpose and nature of transactions in SQL Server:
Distributed Transactions:
You can use Distributed transactions which specifies the start of a SQL distributed transaction managed by Microsoft Distributed Transaction Coordinator (MS DTC). This is only applicable to SQL Server and no Azure. Transaction-level snapshot isolation does not support distributed transactions.Arguments:
transaction_name
Is a user-defined transaction name used to track the distributed transaction within MS DTC utilities. transaction_name must conform to the rules for identifiers and must be <= 32 characters.@tran_name_variable
Is the name of a user-defined variable containing a transaction name used to track the distributed transaction within MS DTC utilities. The variable must be declared with a char, varchar, nchar, or nvarchar data type.
Jeanne also includes the important comment that nested transactions don’t really work the way you’d expect them to. I probably could have ended that last sentence early with, “don’t really work.”