Are you using Delete Portal Row?
And have you selected "Allow deletion..." in the portal setup?
Thanks for your reply, yes I have already used both options. I have written "delete portal row" script option in the button and also select "allow delete option" in portal setting but still its not working so need more suggestion.
In your relationship
File>Manage>Database...relationships tab. Doubleclick on the [=] connection and describe for us which checkboxes at the bottom of the window are checked.
Is your relationship setup automatically deleting the parent record when the child record is deleted?
In other words, is the delete portal row functioning correctly, and is the deleted parent record thus an unwanted side effect?
Thanks it solve actually that is the actual problem.