How to use Database adapter as inbound adapter without having polling strategies?

Question

Hi All,
I have a requirement wherein I have to use Database adapter to retrieve the data for every half an hour from one(X app) database and update that data into another application(Y app) .That database adapter will be along with BPEL process.My Flow would be like this:
Database Adapter( In 'exposed services' section) ----->   BPEL (in 'Components') -----> Y app service( in 'External References' section)
My questions for each step are below
     1) I have to retrieve the data from database(x app database) for every half an hour.So I have to schedule my whole process such that it should execute for every half an hour.
Means I have to get  whatever the data is updated in the last half an hour in that database.
      The database adapter should be inbound in SOA composite editor(in 'Exposed services' section).
But in order to have inbound adapter,we have select the 'Poll for New or Changed Records in a Table' option in turn we have to select one of polling operations below:
         Delete the Row(s) that were Read
Update a Field in the [Table_Name] Table (Logical Delete)
Update a Sequencing Table
Update an External Sequencing Table on a Different Database
Control Table Strategy
But the problem is I don't have any control on the database(X app database) ,So (I can't update any data on that table,because that table may not have a field or table to update the processed rows)I can't choose any of the above operations.
How can I achieve what I want that is to retrieve the data and schedule the process?
Thanks in advance.

Answer 1

Hi Heckler,
  Thank you very much for your answer that I can proceed further somehow.
I still need to have some clarifications.
In order to have a process which retrieves the data (Inbound operation) and updates the data into other application, the data(from X app)  should be the request(through DB adapter) of the BPEL process.
X app does not do anything to send.We have(the BPEL process) to receive the data (or) no event is triggered.
The flow :
Database Adapter( In 'exposed services' section to retrieve data) ----->   BPEL (in 'Components') -----> Y app service( in 'External References' section)
How can we ensure the data will be  request to BPEL process(means it will be in 'exposed services' section in SOA composite editor) for every half an hour if we use pick activity and database adapter as first activity?
When we use ''Poll for New or Changed Records in a Table' ,then only adapter becomes inbound and comes into the 'exposed services' section.I can't use it as I don't have any control on the source table.
I have this confusion before starting the process.Please help me to clear out the doubts.
And this whole process should be executed automaticallly for every half an hour(means it creates instance for every half an hour)  Once we build the BPEL process.
How to schedule it?
And where do I need to create control table ?You mean I have to use some different database where in I have to create the table?