关于laravel事务

        DB::beginTransaction();
        foreach($checkArr[0] as $v){
            $id = explode('-',$v)[0];
            $rank = explode('-',$v)[1] != '' ? explode('-',$v)[1] : 5;
            if(index_friendlink::where('id','=',$id)->pluck('online') == 1){
                $updrank = index_friendlink::find($id);
                $updrank -> rank = $rank;
                $updrank -> save();
            }
        }
        $ret = index_friendlink::where('online','=','1')->get();
        foreach($ret as $v) {
            $retRank[] = $v->rank;
        }
        if (count($retRank) != count(array_unique($retRank))) {
            DB::rollback();
            echo '2';
            exit;
        }
        DB::commit();
        
        
        怎么回滚不了，第一次使用laravel，求大神解答，数据库已改成innodb

        DB::beginTransaction();
        foreach($checkArr[0] as $v){
            $id = explode('-',$v)[0];
            $rank = explode('-',$v)[1] != '' ? explode('-',$v)[1] : 5;
            if(index_friendlink::where('id','=',$id)->pluck('online') == 1){
                $updrank = index_friendlink::find($id);
                $updrank -> rank = $rank;
                $updrank -> save();
            }
        }
        $ret = index_friendlink::where('online','=','1')->get();
        foreach($ret as $v) {
            $retRank[] = $v->rank;
        }
        if (count($retRank) != count(array_unique($retRank))) {
            DB::rollback();
            echo '2';
            exit;
        }
        DB::commit();
        
        
        怎么回滚不了，第一次使用laravel，求大神解答，数据库已改成innodb