procedure TForm1.Button1Click(Sender: TObject);
function check:boolean;
begin
  result:=true;
  if trim(edesc.text)='' then
    result:=false;
end;
begin
if check then
begin
  zquery1.sql.text:='Insert ...'
end
else
begin
  messagedlg('Error, no description captured!!!',mterror,[mbok],0);
end;
end;