Passing from Server to Client After

I have created a button that works very well. It asks if a record has been selected in Client Before and the function works very well. The Client After also displays the message saying its been updated which is also fine.
My problem is, I want to display the message 'No record was selected' if they say it has been but no button was selected.
The code I'm trying in the Server is:
$record = $button->getCurrentRecord();

if($record["L_id"] ==NULL)

{$params["agree"]="No";

$sql="insert into Dummy_Table (DT_details) values ('params are null')";

DB::Exec($sql);}
for some reason are record gets put into the dummy table even if it isn't null.