Using Transactions with Distributed Queries
SQL Server 2005 supports transaction-based access to external data using the ITransactionLocal (local transaction) and ITransactionJoin (distributed transactions) OLE DB interfaces.
Using distributed transactions, SQL Server ensures that a transaction involving multiple nodes is either committed or rolled back in all the nodes. If the provider does not support participating in a distributed transaction (does not support ITransactionJoin), only read-only operations are allowed against that provider when inside a transaction.
See Also
Concepts
Guidelines for Using Distributed Queries
Distributed Queries
Transactions (Database Engine)