Database Reference
In-Depth Information
Traditional DB Adapter implementation
Any ABCS elements should be abstracted through OSB as we have learned in the previous
chapters. Let us repeat that again for better modularity and composability. We should avoid
direct Adapters connection to the Enterprise Business Flows. In other words, our task-or-
chestration services must not become hybrid; otherwise, business logic will be polluted by
TP API specific logic. The following example is based on an absolutely standard Oracle
technique, so for brevity, we will not overburden you with screenshots, as they are quite
obvious. Three tools will be required—JDeveloper and Eclipse with OEPE for develop-
ment and SoapUI ideally for testing.
Tip
Do not follow this example right away, please read it first.
This is primarily an architectural exercise (although every step can be useful for an OSB
OEPE developer):
1. Let's start with the creation of DB Adapter in JDev. Create a new SOA Project and
choose the
Empty Composite
template.
2. Drag
DB Adapter
from
Service Adapters
to the left swimming lane; it will start
Adapter Wizard
. Use a DB of your choice. We will use the
Service
table from a
custom ESR realization from the previous chapter. Give a meaningful name to
your adapter.
3. As all adapters are WLS resources, JDBC Application Modules shall be estab-
lished for our application server. Technically, the JNDI is the lookup mechanism,
allowing you to dynamically resolve the connection property of a JDBC Connec-
tion object by JNDI alias. The connection name shall be unique. Remember, WLS
Connection Factories are deprecated.
4. Use a DB connection from the Offline DB ESR project or create a new one.
Provide a JNDI name, which we will use on our Application server.
5. For simplicity, use only the
Select as a DB Operation
option on Service Table. We
can maintain relations between Service and Service Engine tables. We also can ap-
ply the attribute filtering.
6. We can define select criteria, selecting only Rule functions, based on the DB Rule
execution engine (NDS).
7. Finalize the wizard, generating WSDL, XSD, JCA configuration, and TopLink
mappings. We will use these files in our OSB project.
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