在SQL語句中添加PHP的時間限制？

目前在我的代碼中，任何學生都可以留下任何數量的反饋。我想這樣做，所以每個學生只能在一個學期內給出兩個反饋。在SQL語句中添加PHP的時間限制？

我想我也必須在MySQL中應用某種主鍵概念呢？

這裏是我的參考代碼：

<?php 
session_start(); 

if (isset($_SESSION['user_id'])) { 
    if (isset($_SESSION['user_id']) && isset($_POST['r1']) && isset($_POST['r2']) && isset($_POST['r3']) && isset($_POST['r4']) && isset($_POST['suggestion']) && isset($_POST['module'])) { 
     $module = $_POST['module']; 
     $user = $_SESSION['user_id']; 
     $r1 = $_POST['r1']; 
     $r2 = $_POST['r2']; 
     $r3 = $_POST['r3']; 
     $r4 = $_POST['r4']; 
     $suggestion = $_POST['suggestion']; 
     switch ($module) { 
     case 1: 
      $query_insert = "INSERT INTO `wp_feedback` VALUES ('" . $user . "','wp','" . $r1 . "','" . $r2 . "','" . $r3 . "','" . $r4 . "','" . $suggestion . "')"; 
      if (isset($_POST['submit'])) { 
       if ($query_run = mysql_query($query_insert)) { 
        echo "<script type='text/javascript'>alert('Sucessfull');</script>"; 
        header('Location: feedback.php'); 
       } 
       else { 
        echo "not inserted"; 
       } 
      } 

      break; 

     case 2: 
      $query_insert = "INSERT INTO `wp_feedback` VALUES ('" . $user . "','hssn2','" . $r1 . "','" . $r2 . "','" . $r3 . "','" . $r4 . "','" . $suggestion . "')"; 
      if (isset($_POST['submit'])) { 
       if ($query_run = mysql_query($query_insert)) { 
        echo "<script type='text/javascript'>alert('Sucessfull');</script>"; 
        header('Location: feedback.php'); 
       } 
       else { 
        echo "not inserted"; 
       } 
      } 

      break; 

     case 3: 
      $query_insert = "INSERT INTO `wp_feedback` VALUES ('" . $user . "','dwds','" . $r1 . "','" . $r2 . "','" . $r3 . "','" . $r4 . "','" . $suggestion . "')"; 
      if (isset($_POST['submit'])) { 
       if ($query_run = mysql_query($query_insert)) { 
        echo "<script type='text/javascript'>alert('Sucessfull');</script>"; 
        header('Location: feedback.php'); 
       } 
       else { 
        echo "not inserted"; 
       } 
      } 

     case 4: 
     case 3: 
      $query_insert = "INSERT INTO `wp_feedback` VALUES ('" . $user . "','ped','" . $r1 . "','" . $r2 . "','" . $r3 . "','" . $r4 . "','" . $suggestion . "')"; 
      if (isset($_POST['submit'])) { 
       if ($query_run = mysql_query($query_insert)) { 
        echo "<script type='text/javascript'>alert('Sucessfull');</script>"; 
        header('Location: feedback.php'); 
       } 
       else { 
        echo "not inserted"; 
       } 
      } 

      break; 

     default: 
      echo "select something"; 
      break; 
     } 
    } 
} 
else { 
    echo "<script type='text/javascript'>alert('You must be login to View the contents');</script>"; 
} 

?>

來源

2013-04-14 Ankit rana

插入之前，使用'COUNT（1）'和檢查？ – hjpotter92

[**請不要在新代碼中使用'mysql_ *'函數**]（http://bit.ly/phpmsql）。他們不再被維護[並且被正式棄用]（http://j.mp/XqV7Lp）。看到[**紅框**]（http://j.mp/Te9zIL）？學習[*準備的語句*]（http://j.mp/T9hLWi），並使用[PDO]（http://php.net/pdo）或[MySQLi]（http://php.net/ mysqli） - [這篇文章]（http://j.mp/QEx8IB）將幫助你決定哪個。如果你選擇PDO，[這裏是一個很好的教程]（http://j.mp/PoWehJ）。 – Uby

僞代碼：

SELECT * FROM feedback WHERE studentid=123 AND feedback.insertdate BETWEEN startofthissemesetr AND endofthissemester 

$reccount = number of records returned by the above query 

if ($reccount > 1) { 

    echo "sorry, you already submitted 2 feedbacks this semester!"; 

} else { 

    echo "thank you for submitting your feedback!"; 
    insert feedback into DB 

}

來源

2013-04-14 13:52:14 michi

在SQL語句中添加PHP的時間限制？

回答

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