I am getting this kind of questions quite often:
"I have report with form for modifications. After clicking on the link the form related to this report pops up. Often this is done by at least two users trying to modify one and the same record simultaneously. In such cases the application raises - "ORA-20001: Current version of data in database has changed since initiated update process. Error Unable to process row ....(table name)".
Could you give some advice or give and example how to handle this in a more user friendly manner?"
I created an example in my Demo Application showing how this can be done:
which also includes a step by step guideline.
There, you may test the validation by starting a concurrent update process and trying to update the data on the parent page.