MySQL插入然後更新表數據

Question

嘿我遇到了我的SQL/PHP/JAVA應用程序中的一個小問題我希望你們可以幫助:) 我有一個Java應用程序，當運行連接到我的網站時，Java應用程序驗證它正在運行它與我的網站交談，我的網站將會話Id分配給Java應用程序和網站本身。

很酷我們到目前爲止好嗎？

好的我的java應用程序定期發送數據到一個名爲Dashboard.php的頁面我想要做的是將數據保存到我的Mysql表中，然後當我的Java應用程序從Dashboard.php接收到新數據時， sessionID是相同的我想表更新到剛剛收到的新數據

這裏是我到目前爲止雖然它不工作的PHP。

function update($script_name, $version, $runtime, $status, $ranged, $attack, $defense, $strength, $magic, $sessionID, $username) 
{ 
    global $db; 
    $sql = "SELECT * FROM Dashboard WHERE session_id = '$sessionID'"; 
    try { 
     $results = $db->query($sql); 
     if ($results->rowCount() <= 0) { 
      $query = "INSERT INTO Dashboard (script_name, version, runtime, status, ranged, attack, defense, strength, magic, session_id, username) VALUES ('$script_name', '$version', '$runtime', '$status', '$ranged', '$attack', '$defense', '$strength', '$magic', '$sessionID', $username)"; 
      $db->exec($query); 
     } else { 
      foreach ($results as $row) { 
       $timerunnew = $row['runtime'] + $runtime; 
       $v4new = $row['ranged'] + $range; 
       $v5new = $row['attack'] + $attack; 
       $v6new = $row['defense'] + $defense; 
       $v7new = $row['strength'] + $strength; 
       $v8new = $row['magic'] + $magic; 
      } 
      $db->exec("UPDATE Dashboard SET `runtime` = $timerunnew, `ranged` = $v4new, `attack` = $v5new, `defense` = $v6new, `strength` = $v7new, `magic` = $v8new WHERE session_id = '$sessionID'"); 
     } 
    } catch (PDOException $ex) { 
     echo "fail"; 
    } 
} 

香港專業教育學院還試圖用ON DUPLICATE KEY UPDATE value = VALUES(value)但我有沒有運氣沒有任何人有一個解決方案進行試驗？任何幫助，將不勝感激

Answer 1

如果這是記錄可以被插入到Dashboard表的唯一方法，那麼它是不可能的兩個記錄共享同一session_id（保存爲SELECT和INSERT之間出現的競爭冒險命令）。在這種情況下，你應該：

1. 確保有上session_id定義的UNIQUE鍵：

   ALTER TABLE Dashboard ADD UNIQUE KEY (session_id); 
   

2. 使用INSERT ... ON DUPLICATE KEY UPDATE，最好有一個適當的參數化準備好的語句：

   $qry = $db->prepare(' 
       INSERT INTO Dashboard (
       script_name, version, runtime, status, ranged, attack, 
       defense, strength, magic, session_id, username 
   ) VALUES (
       :script_name, :version, :runtime, :status, :ranged, :attack, 
       :defense, :strength, :magic, :session_id, :username 
   ) ON DUPLICATE KEY UPDATE 
       runtime = runtime + VALUES(runtime), 
       attack = attack + VALUES(status), 
       defense = defense + VALUES(defense), 
       strength = strength + VALUES(strength), 
       magic = magic + VALUES(magic) 
   '); 
   
   $qry->execute([ 
       ':script_name' => $script_name, 
       ':version'  => $version, 
       ':runtime'  => $runtime, 
       ':status'  => $status, 
       ':ranged'  => $ranged, 
       ':attack'  => $attack, 
       ':$defense' => $defense, 
       ':strength' => $strength, 
       ':magic'  => $magic, 
       ':session_id' => $sessionID, 
       ':username' => $username 
   ]);