Attribute Description
Disabled Ignores all transactions in the current context.
NotSupported Creates the component in a context with no governing transaction.
Required Uses the current transaction by default. Creates a new transaction if necessary.
RequiresNew Always creates the component with a new transaction. Required for a Web service.
Supported Uses the current transaction, if one exists.

Table 1 Raise Component Consciousness.
Each attribute corresponds to a different level of transaction "awareness" for the component. For Web services, you must use the RequiresNew attribute. Web services cannot participate in ongoing transactions because transactions don't flow across methods in a Web service.