PHP-试图将Mysqli转换为PDO

Question

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;
    }

Answer 1

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>";                   
}