Bring Your Own Transaction (BYOT)
BYOT allows a component to be created with or to inherit an external transaction. That is, a component that does not already have an associated transaction can acquire a transaction. Currently, MTS transactions are automatic; whether a component instance lives in a transaction is determined at creation time. The transactional attributes of a component and its creator determine what transaction is associated with a given instance. In all cases, MTS controls transaction lifetimes. COM+ extends this to allow setting an arbitrary pre-existing DTC or TIP transaction as the transaction property of a new component's context. This allows configured components to be associated with transactions whose lifetimes are controlled by a TP monitor, OTS, or DBMS.
Note
BYOT transactions must be used with caution. In certain situations, they can result in a transaction spanning multiple synchronization domains—that is, they allow parallelism with a transaction, causing a deadlock condition. Automatic transactions, rather than BYOT transactions, are the preferred programming model for writers of business components.
The interfaces for BYOT transactions include the ICreateWithTransactionEx interface and the ICreateWithTipTransactionEx interface. The ICreateWithTransactionEx interface creates an object that is enlisted within a manual transaction. The ICreateWithTipTransactionEx interface creates an object that is enlisted within a manual transaction using the Transaction Internet Protocol (TIP).
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