How to specify custom SQL in polling db adapter with logical delete option

Question

Hi all,
I am writing a SOA composite app using JDeveloper SOA Suite 11.1.1.4 connecting to a SQL Server db using a polling DB Adapter with the logical delete option to send data to a BPEL process.
I have requirements which go beyond what is supported in the JDeveloper UI for DB Adapter polling options, namely:
* update more than one column to mark each row read, and
* specify different SQL for the logical delete operation based on whether bpel processing of the data polled was successful or not.
A complicating factor is that the polling involves two tables. Here is my full use-case:
1) Polling will select data derived from two tables: e.g. 'headers' and 'details' simplified for this example:
table: headers
hid - primary key
name - data label
status - 'unprocessed', 'processed', or 'error'
processedDate - null when data is loaded, set to current datetime when row is processed
table: details
hid - foreign key pointed at header.hid
attr - data attribute name
value - value of data attribute
2) There is a many:1 relationship between detail and header rows through the hid columns. The db adapter polling SELECT shall return results from an outer join consisting of one header row and the associated detail rows where header.status = 'unprocessed' and header.hid = details.hid. (This is supported by the Jdeveloper UI)
3) The polled data will be sent to be processed by a bpel process:
3.1) If the bpel processing succeeds, the logical delete (UPDATE) operation shall set header.status = 'processed', and header.processedDate = 'getdate()'.
3.2) If bpel processing fails (e.g. hits a data error while processing the selected data) the logical delete (UPDATE) operation shall set header.status = 'failed', header.processedDate = 'getdate()', and header.errorMsg = '{some text returned from bpel}'.
Several parts of #3 are not supported by the JDeveloper UI: updating multiple columns to mark the row processed, using getdate() to populate a value of one of those column updates, doing different update operations based on the results of the BPEL processing of the data (success or error), and using data obtained from BPEL processing as a value of those column updates (error message).
I have found examples which describe specifying custom SQL using the polling delete option to create a template then modifying the toplink file(s) to specify custom select and update SQL to implement a logical delete. (e.g. http://dlimiter.wordpress.com/2009/11/05/advanced-logic-in-oracle-bpel-polling-database-adapter/ and http://myexperienceswithsoa.blogspot.com/2010/06/db-adapter-polling-tricks.html). But none of them match what I've got in my project, in the first case because maybe because I'm using a higher version of JDeveloper, and in the second I think because in my case two tables are involved.
Any suggestions would be appreciated. Thanks, John

Answer 1

Hi John,
You've raised a good scenario.
First of all let me say that the purpose of the DB polling transaction, is to have an option to initiate a process from a DB table/view and not to update multiple fields in a table (or have other complex manipulation on the table).
So, when choose to update a field in a record, after reading it, you are "telling" the engine not to poll this record again. Sure, i guess you can find a solution/workaround for it, but I don't think this is the way....
The question now is what to do?
You can have another DB adapter where you can update the data after finishing the process. In that case, after reading the data (on polling transaction) - update the header.status = 'processed' for example, and after processing the selected data update the rest of the fields.
Hope it make some sense to you.
Arik