Question

我尝试转换为使用PDO，但似乎无法在循环时从我的PDO获得结果。

这个mysql语句给了我结果：

$q = mysql_query("SELECT * FROM artist ORDER BY artist ASC");
while ($row = mysql_fetch_array($q)) {
  $theartist .= '<option value="'.($row['artist_id']).'">'.($row['artist'])."</option>";
}

PDO数据库连接（似乎可行）

//the below isn't throwing any errors
$host='localhost';
$dbname='james_test';
$user='test';
$pass='testpass';

try {
  # MySQL with PDO_MYSQL
  $DBH = new PDO("mysql:host=$host;dbname=$dbname", $user, $pass);
}
catch(PDOException $e) {
    echo $e->getMessage();
}

此PDO声明未给我任何结果：

$query = $DBH->prepare("SELECT * FROM artist ORDER BY artist ASC");
while($row = $query->fetch(PDO::FETCH_ASSOC)) {
    $theartist .= '<option value="'.($row['artist_id']).'">'.($row['artist'])."</option>";
}

Answer 1

您错过了运行查询的步骤。使用PDO，您可以准备查询以优化性能并帮助防止SQL注入，但您仍然必须执行＆＃34;执行＆＃34;声明。

$query = $DBH->prepare("SELECT * FROM artist ORDER BY artist ASC");
$result = $query->execute();
while($row = $result->fetch(PDO::FETCH_ASSOC)) {
    $theartist .= '<option value="'.($row['artist_id']).'">'.($row['artist'])."</option>";
}

相关PHP手册条目：

http://php.net/manual/en/pdostatement.execute.php

http://php.net/manual/en/pdo.prepare.php

Answer 2

这只是通过稍微更改代码来实现它。



//$query = $DBH->prepare("SELECT * FROM artist ORDER BY artist ASC");
$rows = $DBH->query("SELECT * FROM artist ORDER BY artist ASC");

//while($row = $query->fetch(PDO::FETCH_ASSOC)) {
if ($rows) {
  foreach ($rows as $row) {
      $theartist .= ''.($row['artist'])."";
  }
}

修改查询函数可以一次性准备和执行，如果您没有在查询中使用变量，则查询函数非常有用。

如何有效地将这个工作的mysql语句转换为PDO？

2 个答案: