adodataset1.Close;
adodataset1.CommandText:='select * from table1 where id='''+txtname.Text +'''';
adodataset1.Open;
if not adodataset1.Eof then
begin
adodataset1.Fields[0].DisplayLabel:='姓名';
application.MessageBox('该信息已存在!','提示',mb_ok);
exit
end;
adodataset1.Append;
adodataset1.Fields[0].AsString:=txtname.text;
adodataset1.Post;