1) Drag and Drop a Database Adapter in external reference line and click next
2) Give the name of you DB Adapter and click next. In next step choose your database or create a new connection
3) The most important thing here is to create a data source in your Weblogic console. That data source you will use here in JNDI name. As you can see EBS is the name of my data source that i have configured on Weblogic, Without it your Webservice will not work
4) In next step check call to stored procedure or a function
5) From next step select your schema and stored procedure. My procedure has two output parameter.
6) Click next, next and then finish this wizard your JDeveloper will be like this
Now your DB adapter is configured you can call this using BPEL Process and test it. The main thing is to set JNDI name, It should be configured correctly. Follow the following link if you want to call this DB Adapter using BPEL Process.
http://technasir.blogspot.com/2013/08/store-procedure-invocation-using-bpel.html