專案背景：
新專案是一個分銷系統，核心技術就是無限極分類，每個會員都可以邀請別人進入這個團隊，會員可以升級，可以享受獎勵，前提是不斷地邀請別人加入，這樣每個團隊的長遠可以層層繫結關係。
資料庫設計：

資料庫的user表這樣設計，invite_id為邀請人id,parent_id為直接父級id,path表示當前會員在團隊裡的路徑，當前的會員可以通過parent_id一直找到他的父級，直到最頂層。也可以通過parent_id找到他的直接邀請人。
下面以一段程式碼說明無限極分類和遞迴的關係：

程式碼片段：

static function teamUpgrade
 
($parent_id)
    {
        $userObj = new IModel('user');
        $parentRow = $userObj->getObj('id = '.$parent_id);

        //獲取children資訊
        $childrenObj = new IQuery('user');
        $childrenObj->where = 'parent_id='.$parent_id;
        $childrenObj->fields = 'id,path,group_code';
        $childrenRows
 
 = $childrenObj->find();

        //當前使用者直接邀請人
        $inviteSum = self::getInviteSum($parent_id);

        //查詢當前使用者團隊人數
        $group_sum = self::getAllTeam($parent_id,$parentRow['path'],$parentRow['group_code']);

        //根據團隊總數和直接邀請人數判斷是否升級(常規情形)
        switch ($group_sum['group_sum']-1) {
            case
 
 10:
                if ($inviteSum['invite_sum'] >= 2) {
                    $levelTmp = self::teamUpdate($parentRow['level']);
                }
                break;
            case 30:
                if ($inviteSum['invite_sum'] >= 3) {
                    $levelTmp = self::teamUpdate($parentRow['level']);
                }
                break;
            //A區或者B區大於等於30單(最小區大於等於30單)
            case 100:
                if ($childrenRows[0]['path'] && $childrenRows[1]['path'])
                {
                    //A,B區同時存在,並且大於等於30單
                    $aZone = self::getAllTeam($childrenRows[0]['id'],$childrenRows[0]['path'],$childrenRows[0]['group_code']);
                    $bZone = self::getAllTeam($childrenRows[1]['id'],$childrenRows[1]['path'],$childrenRows[1]['group_code']);

                    if($aZone['group_sum']>=30 && $bZone['group_sum']>=30)
                    {
                        $levelTmp = self::teamUpdate($parentRow['level']);
                    }

                }
                break;
            case 300:
                if ($childrenRows[0]['path'] && $childrenRows[1]['path'])
                {
                    //A,B區同時存在,並且大於等於100單
                    $aZone = self::getAllTeam($childrenRows[0]['id'],$childrenRows[0]['path'],$childrenRows[0]['group_code']);
                    $bZone = self::getAllTeam($childrenRows[1]['id'],$childrenRows[1]['path'],$childrenRows[1]['group_code']);

                    if($aZone['group_sum']>=100 && $bZone['group_sum']>=100)
                    {
                        $levelTmp = self::teamUpdate($parentRow['level']);
                    }

                }
                break;
            case 900:
                if ($childrenRows[0]['path'] && $childrenRows[1]['path'] && $childrenRows[2]['path'])
                {
                    //A,B,C區同時存在,最小兩邊之和大於300單
                    $aZone = self::getAllTeam($childrenRows[0]['id'],$childrenRows[0]['path'],$childrenRows[0]['group_code']);
                    $bZone = self::getAllTeam($childrenRows[1]['id'],$childrenRows[1]['path'],$childrenRows[1]['group_code']);
                    $cZone = self::getAllTeam($childrenRows[2]['id'],$childrenRows[2]['path'],$childrenRows[2]['group_code']);

                    $sum = array($aZone['group_sum'],$bZone['group_sum'],$cZone['group_sum']);
                    array_multisort($sum,SORT_ASC,SORT_NUMERIC);
                    if($sum[0] + $sum[1] >= 300)
                    {
                        $levelTmp = self::teamUpdate($parentRow['level']);
                    }

                }
                break;
            case 2500:
                if ($childrenRows[0]['path'] && $childrenRows[1]['path'] && $childrenRows[2]['path'] && $childrenRows[3]['path'])
                {
                    //A,B,C,D區同時存在,最小三邊之和大於900單
                    $aZone = self::getAllTeam($childrenRows[0]['id'],$childrenRows[0]['path'],$childrenRows[0]['group_code']);
                    $bZone = self::getAllTeam($childrenRows[1]['id'],$childrenRows[1]['path'],$childrenRows[1]['group_code']);
                    $cZone = self::getAllTeam($childrenRows[2]['id'],$childrenRows[2]['path'],$childrenRows[2]['group_code']);
                    $dZone = self::getAllTeam($childrenRows[3]['id'],$childrenRows[3]['path'],$childrenRows[3]['group_code']);

                    $sum = array($aZone['group_sum'],$bZone['group_sum'],$cZone['group_sum'],$dZone['group_sum']);
                    array_multisort($sum,SORT_ASC,SORT_NUMERIC);
                    if($sum[0] + $sum[1] + $sum[2]>= 833)
                    {
                        $levelTmp = self::teamUpdate($parentRow['level']);
                    }

                }
                break;
            case 7500:
                if ($childrenRows[0]['path'] && $childrenRows[1]['path'] && $childrenRows[2]['path'] && $childrenRows[3]['path'])
                {
                    //A,B,C,D區同時存在,最小三邊之和大於2500單
                    $aZone = self::getAllTeam($childrenRows[0]['id'],$childrenRows[0]['path'],$childrenRows[0]['group_code']);
                    $bZone = self::getAllTeam($childrenRows[1]['id'],$childrenRows[1]['path'],$childrenRows[1]['group_code']);
                    $cZone = self::getAllTeam($childrenRows[2]['id'],$childrenRows[2]['path'],$childrenRows[2]['group_code']);
                    $dZone = self::getAllTeam($childrenRows[3]['id'],$childrenRows[3]['path'],$childrenRows[3]['group_code']);

                    $sum = array($aZone['group_sum'],$bZone['group_sum'],$cZone['group_sum'],$dZone['group_sum']);
                    array_multisort($sum,SORT_ASC,SORT_NUMERIC);
                    if($sum[0] + $sum[1] + $sum[2] >= 2500)
                    {
                        $levelTmp = self::teamUpdate($parentRow['level']);
                    }

                }
                break;
            case 16667:
                if ($childrenRows[0]['path'] && $childrenRows[1]['path'] && $childrenRows[2]['path'] && $childrenRows[3]['path'])
                {
                    //A,B,C,D區同時存在,最小三邊之和大於5000單
                    $aZone = self::getAllTeam($childrenRows[0]['id'],$childrenRows[0]['path'],$childrenRows[0]['group_code']);
                    $bZone = self::getAllTeam($childrenRows[1]['id'],$childrenRows[1]['path'],$childrenRows[1]['group_code']);
                    $cZone = self::getAllTeam($childrenRows[2]['id'],$childrenRows[2]['path'],$childrenRows[2]['group_code']);
                    $dZone = self::getAllTeam($childrenRows[3]['id'],$childrenRows[3]['path'],$childrenRows[3]['group_code']);

                    $sum = array($aZone['group_sum'],$bZone['group_sum'],$cZone['group_sum'],$dZone['group_sum']);
                    array_multisort($sum,SORT_ASC,SORT_NUMERIC);
                    if($sum[0] + $sum[1] + $sum[2] >= 5000)
                    {
                        $levelTmp = self::teamUpdate($parentRow['level']);
                    }

                }
                break;
            default:
                # code...
                break;
        }
        /*****非常規情況下的升級結束*****/

        //等級升級和軌道升級
        if($levelTmp)
        {
            //當升級為區代理時,升級為三個軌道,升級為市代理時,升級為四個軌道
            if($levelTmp == 22)
            {
                $pathway=3;
            }
            if($levelTmp == 23)
            {
                $pathway=4;
            }
            if($pathway)
            {
                $userObj->setData(array('level'=>$levelTmp,'pathway'=>$pathway));
            }
            else
            {
                $userObj->setData(array('level'=>$levelTmp));
            }
            $res = $userObj->update('id = '.$parent_id);
        }

        //不管是否升級成功，都有等級獎勵並寫入日誌
        // $parentRow = $userObj->getObj('id = '.$parent_id);//重新查詢，等級可能有變動
        // $levelTmp = $parentRow['level'];
        // $award = self::levelAward($levelTmp);

        //新增等級獎勵寫入日誌(不管是否升級)
        // self::addAward($parent_id,$levelTmp,$award);

        //當前等級下的其他等級如果沒有，獎勵歸當前等級所有
        // self::addPlusAward($parent_id);

        //寫入升級日誌(不計算獎勵)
        if($levelTmp)
        {
            self::upgradeLog($parent_id,$levelTmp);
        }

        *****//判斷父級的父級，存在則遞迴計算
        if($parentRow['parent_id']==0){
            //沒有父級，直接退出
            return;
        }
        //有父級，回撥自身繼續計算
        if($parentRow['parent_id']>0)
        {
            self::teamUpgrade($parentRow['parent_id']);
        }*****

    }

總結：
程式碼的主要邏輯是判斷父級是否滿足升級的條件，滿足的話去更新user表的level欄位並且記入日誌。程式碼的最後判斷當前父級是否還有父級，這個條件是遞迴的入口條件，不然可能導致遞迴會無限迴圈。 該方法的觸發條件是為當前會員設定父級的時候，下級與上級一一繫結樹狀圖的關係，並在升級的時候和遞迴很好的用到了一起。功能是實現了，考慮效能的話肯定還有更好的方法，在今後的工作與學習中會繼續完善它，表達能力有限，相信自己可以不斷進步。