I need to do transformation based on DB check ... If ITEM_ID exists in DB it should not do transformation for that particular ITEM_ID, The ITEM_ID's which are not present in the DB then it should do transformation ..
If you are implementing this in OSB:
Then in your XQuery you can use fn-bea:execute-sql() function to query the DB for existence of current ITEM ID within a if-else block and write transform logic in XQ accordingly.
If you are implementing this in SOA Suite:
Then in your XSLT you can use oraext:lookup-table() function within your XSLT to check the existence of current ITEM ID within a If node and write transform logic in XSLT accordingly.