I apply database trigger on HR_API_TRNASACTION_VALUES, for SSHR on SIT
I want that if any person transaction in pending for approval he can not submitted the same transaction I have creeate one FLEX_STRUCTURE in special information types segment 1 have three type if user alreaday submitted one type and this segment1 type in pending for approval means still in HR_API_TRNASACTION_VALUES so he can not submited the next transaction till first one approve how I can acchive this.
As a thumb rule, no one replies to the post when you mention urgent as everyone is a volunteer here. For urgent requirements you should go to Oracle.
Anyways, you can write a hook in fnd_flex_plsql package to check whether a pending transaction exists with the same type. No need for a database trigger.