异常问题,搞不定

[jczff]

begin
ADOQuery1.Close ;
ADOQuery1.SQL.Clear ;
ADOQuery1.SQL.Add('select * from student');
ADOQuery1.Open ;
ADOQuery1.Append ; //把注册信息写入学期注册表中
ADOQuery1.FieldByName ('stu_id').AsString :=trim(edit1.Text);
ADOQuery1.FieldByName ('stu_name').AsString :=trim(edit2.Text);
ADOQuery1.FieldByName ('stu_sex').AsString :=trim(combobox1.Text);
ADOQuery1.FieldByName ('stu_xi').AsString :=trim(edit4.Text);
ADOQuery1.FieldByName ('stu_class').AsString :=trim(edit5.Text);
ADOQuery1.FieldByName ('stu_tel').AsString :=trim(edit6.Text);
ADOQuery1.Prepared ;
try
ADOConnection1.BeginTrans; //提交事务
ADOQuery1.Post ;
ADOConnection1.CommitTrans ;
MessageBox(handle,'注册成功!','提示',MB_OK+MB_ICONINFORMATION);
except
ADOConnection1.RollbackTrans ; //提交失败,事务回滚
MessageBox(handle,'注册失败!','提示',MB_OK+MB_ICONWARNING);
end;

end;
当我插入同样的数据(关键字)时,程序运行出错
这个异常感觉没起到作用.

[Elysium]

调试状态下无效，单独运行可执行程序就生效了

[jczff]

谢谢