//事务开启
$m_user=M('test');
$m_user->startTrans();
try{
     $m_user->where($where)->delete();
     M('test')->where($where)->delete();
     $txt['msg']='成功';
     $txt['code']=1;
}catch(exception $e){
     $m_user->rollback();
     $txt['msg']='失败';
     $txt['code']=0;
}
 $m_user->commit();
 echo json_encode($txt);exit;