使用PHP，PDO和MySql显示在一个页面上的两个表格

Question

我试图创建一个CRUD仪表板，使用MySql后端和引导前端用PHP和PDO与数据库进行通信。我是网页开发的一个小老头，但不是编码。

目标是创建一个Web应用程序来记录我的患者咨询。因此，我的表结构是一个单独的“主”表和两个与“主”表关联的子表，名为“咨询”和“过程”。

我想做一个仪表板，在那里显示我的“主”表，然后在它下面添加两个子表。 （稍后我会更好地设计风格，但我试图让它工作）。

以下是我能想到的最好的MWE（如果有人有一个更简单的解决方案，会喜欢它）。第一个“日志病人”表运作良好，并能很好地显示病人行。它的第二个表是问题，特别是：

$sql = "SELECT * FROM proc"; 
if($result = $pdo->query($sql)){ 
if($result->rowCount() > 0){ 

这是我不断收到错误的区域。错误是：

Fatal error: Uncaught Error: Call to a member function query() on null in /home/paincl5/public_html/logbook/logbook.php:110 Stack trace: #0 {main} thrown in /home/paincl5/public_html/logbook/logbook.php on line 110

在管线110中的代码是

unset($pdo); 

我完整的代码：

<div class="wrapper"> 
    <div class="container-fluid"> 
     <div class="row"> 
      <div class="col-md-12"> 
       <div class="page-header clearfix"> 
        <h2 class="pull-left">Logbook Patients</h2> 
        <a href="create.php" class="btn btn-success pull-right" >Add New Patient</a> 


       </div> 
       <?php 
       // Include config file 
       require_once 'config.php'; 

       // Attempt select query execution 
       $sql = "SELECT * FROM main"; 
       if($result = $pdo->query($sql)){ 
        if($result->rowCount() > 0){ 
         echo "<div style='height:300px;overflow-y:scroll;;'>"; 
         echo "<table class='table table-bordered table-striped'>"; 
          echo "<thead>"; 
           echo "<tr>"; 
            echo "<th>Surname</th>"; 
            echo "<th>first_name</th>"; 
            echo "<th>DOB</th>"; 
            echo "<th>Hospital</th>"; 
            echo "<th>MRN</th>"; 
            echo "<th>Action</th>"; 
           echo "</tr>"; 
          echo "</thead>"; 
          echo "<tbody>"; 
          while($row = $result->fetch()){ 
           echo "<tr>"; 
            echo "<td>" . $row['Surname'] . "</td>"; 
            echo "<td>" . $row['first_name'] . "</td>"; 
            echo "<td>" . $row['DOB'] . "</td>"; 
            echo "<td>" . $row['Hospital'] . "</td>"; 
            echo "<td>" . $row['MRN'] . "</td>"; 
            echo "<td>"; 
             echo "<a href='read.php?id=". $row['id'] ."' title='View Record' data-toggle='tooltip'><span class='glyphicon glyphicon-eye-open'></span></a>"; 
             echo "<a href='update.php?id=". $row['id'] ."' title='Update Record' data-toggle='tooltip'><span class='glyphicon glyphicon-pencil'></span></a>"; 
             echo "<a href='delete.php?id=". $row['id'] ."' title='Delete Record' data-toggle='tooltip'><span class='glyphicon glyphicon-trash'></span></a>"; 
            echo "</td>"; 
           echo "</tr>"; 
          } 
          echo "</tbody>";        
         echo "</table>"; 
         echo "</div>"; 
         // Free result set 
         unset($result); 
        } else{ 
         echo "<p class='lead'><em>No records were found.</em></p>"; 
        } 
       } else{ 
        echo "ERROR: Could not able to execute $sql. " . $mysqli->error; 
       } 

       // Close connection 
       unset($pdo); 
       ?> 
      </div> 
     </div>   
    </div> 
</div> 



// Procedure Table 
<div class="wrapper"> 
    <div class="container-fluid"> 
     <div class="row"> 
      <div class="col-md-12"> 
       <div class="page-header clearfix"> 
        <h2 class="pull-left">Procedures</h2> 
        <a href="create_proc.php" class="btn btn-success pull-right" >Add New Procedure</a> 
       </div> 
       <?php 
       // Include config file 
       require_once 'config.php'; 
       // Attempt select query execution 
       $sql = "SELECT * FROM proc"; 
       if($result = $pdo->query($sql)){ 
        if($result->rowCount() > 0){ 
         echo "<div style='height:300px;overflow-y:scroll;;'>"; 
         echo "<table class='table table-bordered table-striped'>"; 
          echo "<thead>"; 
           echo "<tr>"; 
            echo "<th>Procedure Type</th>"; 
            echo "<th>Procedure Name</th>"; 
            echo "<th>Notes</th>"; 
            echo "<th>Action</th>"; 
           echo "</tr>"; 
          echo "</thead>"; 
          echo "<tbody>"; 
          while($row = $result->fetch()){ 
           echo "<tr>"; 
            echo "<td>" . $row['procedure_type'] . "</td>"; 
            echo "<td>" . $row['procedure_name'] . "</td>"; 
            echo "<td>" . $row['notes'] . "</td>"; 
            echo "<td>"; 
             echo "<a href='update.php?id=". $row['id1'] ."' title='Update Record' data-toggle='modal' data-target='#myModal' ><span class='glyphicon glyphicon-pencil'></span></a>"; 
             echo "<a href='delete.php?id=". $row['id1'] ."' title='Delete Record' data-toggle='tooltip'><span class='glyphicon glyphicon-trash'></span></a>"; 
            echo "</td>"; 
           echo "</tr>"; 
          } 
          echo "</tbody>";        
         echo "</table>"; 
         echo "</div>"; 
         // Free result set 
         unset($result); 
        } else{ 
         echo "<p class='lead'><em>No records were found.</em></p>"; 
        } 
       } else{ 
        echo "ERROR: Could not able to execute $sql. " . $mysqli->error; 
       } 

       // Close connection 
       unset($pdo); //Here occurs the error (line 110) 
       ?> 
      </div> 
     </div>   
    </div> 
</div> 

Answer 1

您与unset($pdo)所以任何后续调用试图摧毁你的$pdo变量针对空对象运行方法。

尝试删除对该参考文献的引用unset。

我假设$pdo对象来自config.php。由于您使用的是require_once，因此只会在第一次调用require_once时包含配置文件。这就是为什么$pdo被销毁并且没有被重新创建。