PHP-试图将Mysqli转换为PDO

问题描述：

I am trying to convert the Mysqli code to use PDO

Mysqli code looks like the following (which works great)

$rs = "SELECT * FROM team";

$result = mysqli_query($con,$rs);           
$data = mysqli_num_rows($result);
$responses = array();
    if($data != 0) {
        while($results = mysqli_fetch_assoc($result))
          {
        echo "<tr><td>".$results['code'] ."</td>";
        echo "<td>".$results['username'] ."</td>";                   
        }

My PDO code I tried

    $stmt = $con->prepare("select * from  team");
    $stmt->execute();
    if($stmt->rowCount() > 0)
 $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);

How should I write a while loop here

on w3schools website, the information given to retrieve the records using PDO is as below, which did not say what is V and doesn't say how do I retrieve the fields code and username from the table.

  foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) { 
        echo $v;
    }

我正在尝试将Mysqli代码转换为使用PDO p>

Mysqli代码看起来如下（效果很好） p>

  $ rs =“SELECT * FROM team”; 
 
 $ result = mysqli_query（$ con，$ rs）;  
 $ data = mysqli_num_rows（$ result）; 
 $ responses = array（）; 
 if（$ data！= 0）{
 while（$ results = mysqli_fetch_assoc（$ result））
 {
 \ echo  “＆lt; tr＆gt;＆lt; td＆gt;”。$ results ['code']。“＆lt; / td＆gt;”; 
 echo“＆lt; td＆gt;”。$ results ['username']。“＆lt; / td＆gt;  ;“;  
} 
  code>  pre> 
 
 
我试过的我的PDO代码 p> 
 
 
  $ stmt = $  con> gt;准备（“select * from team”）; 
 $ stmt-＆gt; execute（）; 
 if（$ stmt-＆gt; rowCount（）＆gt; 0）
 $ result = $ stmt-＆gt  ;调用setFetchMode（PDO :: FETCH_ASSOC）;  
  code>  pre> 
 
 我应该如何在w3schools网站上写一个while循环 p> 
 
 
，使用PDO检索记录的信息是 如下所示，它没有说什么是V，也没有说我如何从表中检索字段 code  code>和 username  code>。   p> 
 
 
  foreach（new TableRows（new RecursiveArrayIterator（$ stmt-＆gt; fetchAll（）））$ k =＆gt; $ v）{
 echo $ v; 
  } 
  code>  pre> 
  div>

答

That's a horrifically awful way to select data from a database. It's far more complex than is necessary. I suppose it might be useful in a certain context, but not here.

The simple way is with PDOStatement::fetch. This works in much the same way as mysqli_fetch_assoc. (You don't strictly speaking need to check the row count, though you might have other code if there are no results.)

while ($row = $stmt->fetch()) {
    echo "<tr><td>".$row['code'] ."</td>";
    echo "<td>".$row['username'] ."</td>";                   
}

My preferred way, however, is with PDOStatement::bindColumn, which gets rid of arrays and uses nice plain variables instead:

$stmt->setFetchMode(PDO::FETCH_BOUND);
$stmt->bindColumn('code', $code);
$stmt->bindColumn('username', $username);
while ($row = $stmt->fetch()) {
    echo "<tr><td>$code</td>";
    echo "<td>$username</td>";                   
}

答

$stmt = $con->prepare("select * from  team");
$stmt->execute();
if($stmt->rowCount() > 0)
{
  while($row = $stmt->fetch(PDO::FETCH_ASSOC))
  {
    echo "<tr><td>".$row['code'] ."</td>";
    echo "<td>".$row['username'] ."</td>"; 
  }
}

答

It's PDO, so everything is MUCH simpler:

foreach ($con->query("SELECT * FROM team") as $results) {
    echo "<tr><td>".$results['code'] ."</td>";
    echo "<td>".$results['username'] ."</td>";                   
}

答

$rs = "SELECT * FROM team";
$stmt = $pdo->query($rs );
while ($row = $stmt->fetch())
{
    echo "<tr><td>".$row ['code'] ."</td>";
    echo "<td>".$row ['username'] ."</td></tr>";  
}

$stmt = $pdo->query($rs );
foreach ($stmt as $row)
{
    echo "<tr><td>".$row ['code'] ."</td>";
    echo "<td>".$row ['username'] ."</td></tr>"; 
}

$data = $pdo->query($rs )->fetchAll();
foreach ($data as $row)
{
    echo "<tr><td>".$row ['code'] ."</td>";
    echo "<td>".$row ['username'] ."</td></tr>"; 
}

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