Databases Reference
In-Depth Information
To do this, drag a
Remove Entity
activity from the component pallet on to your
BPEL process. Double-click on it; this will open the
Remove Entity
activity window,
as shown in the following screenshot:
Here, we just need to specify the name of the entity variable that we want to remove.
Note that this should be an entity variable that we have already bound to an SDO,
either through a
Create Entity
or
Bind Entity
activity.
Exposing the SDO as a business service
The one issue which we have avoided so far is that if we look at the interfaces of
our SDO objects, then they are very much driven by the underlying structure of the
database tables on which they are based.
If we were to follow the strict interpretation of our SOA blueprint, as laid out in
Chapter 10, oBay Introduction
, you could argue that they belong in the application
services layer, and therefore should always be called via a virtual services layer.
This, in the preceding examples, is clearly not the case.
There are a couple of ways to counter this point. The first is to simply accept that
the ListingSDO, while an entity service, is not intended to be a reusable service in its
own right. It is just a component of our Auction and ListItem composite, and thus all
components, while not necessarily packaged as part of the same JDeveloper project,
will always be deployed together.
However, in other cases it may make sense that the SDO is a reusable service in its
own right. In this scenario, it's quite straightforward to use a Mediator to invoke
the ADF-BC service, which can then perform the transformation from our canonical
model to that of the SDO and vice versa. Then, we can expose it as a completely
abstracted Business Service.
