AIA 3.0 : Service Constructor support for DB adapter and JCA adapters.

As per the AIA developer's guide
"Currently the Service Constructor supports only services that have an exposed interface and cannot yet directly invoke JCA adapters such as the File or DB adapter."

Incase you want to invoke DB adapter in your ProviderABCS or receiving DB records in your RequestorABCS, the Oracle recommended way is to create the adapter as a separate composite and use the same in your AIA Service Constructor.

I came across a similar situation where my RequestorABCS had to be kicked off when SAP sends an idoc (via SAP Channel) or if I had to poll records from a DB table. In both cases I had to create the SAP adapter/DB adapter as a separate composite and invoke the RequestorABCS wsdl from there.
This approach also ensures reusability of the adapter composite code incase other ABCS want to use it.