delphi主键重复报错
我用的是delphi,用try except想避免输入相同主键的记录时给出提示，可是第一次输入相同主键还会执行excpt语句，提示“此记录已存在”，再次输入相同记录时，就会报错，不知道怎么回事，希望大家能够帮帮忙
下面是我的代码
adotable1.open;
adotable1.Last;
if (combobox1.Text ='') or (combobox2.Text ='') or (combobox3.Text ='') or (edit1.Text ='') or (edit2.Text ='') or (edit3.Text ='') or (edit4.Text ='') or (edit6.Text ='') or (edit8.Text ='') or (edit9.Text ='') then
showmessage('您输入的信息不完整!')
else
begin
try
begin
adotable1.append;
adotable1['年']:=combobox1.Text;
adotable1['月']:=combobox2.Text;
adotable1['科室']:=combobox3.text;
adotable1['姓名']:=edit1.Text;
adotable1['岗位系数']:=edit2.Text;
adotable1['职称系数']:=edit3.Text;
adotable1['基本工资']:=edit4.Text;
adotable1['个人综合得分']:=edit6.Text;
adotable1['扣考勤款']:=edit7.Text;
adotable1['实发绩效工资']:=edit8.Text;
adotable1['净领绩效工资']:=edit9.Text;
adotable1.Post;
edit1.setfocus;
with ADOQuery1 do
application.MessageBox('信息添加成功','提示',64) ;
end;
except
showmessage('此记录已存在！');



end;

end;



[解决办法]
...

try
adotable1.Post;
except
showmessage('此记录已存在！');
adotable1.Cancel;
exit;
end;