30

我正在慢慢地将我的所有功能LAMP websites从mysql_功能转移到PDO功能，并且我已经碰到了我的第一堵砖墙。我不知道如何使用参数循环遍历结果。我对以下内容很好：

foreach ($database->query("SELECT * FROM widgets") as $results)
{
   echo $results["widget_name"];
}

但是，如果我想做这样的事情：

foreach ($database->query("SELECT * FROM widgets WHERE something='something else'") as $results)
{
   echo $results["widget_name"];
}

显然，“其他东西”将是动态的。

4

3 回答 3

73

这是使用 PDO 连接到数据库的示例，告诉它抛出异常而不是 php 错误（将有助于您的调试），并使用参数化语句而不是自己将动态值替换到查询中（强烈推荐）：

// connect to PDO
$pdo = new PDO("mysql:host=localhost;dbname=test", "user", "password");

// the following tells PDO we want it to throw Exceptions for every error.
// this is far more useful than the default mode of throwing php errors
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

// prepare the statement. the placeholders allow PDO to handle substituting
// the values, which also prevents SQL injection
$stmt = $pdo->prepare("SELECT * FROM product WHERE productTypeId=:productTypeId AND brand=:brand");

// bind the parameters
$stmt->bindValue(":productTypeId", 6);
$stmt->bindValue(":brand", "Slurm");

// initialise an array for the results
$products = array();
$stmt->execute();
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
    $products[] = $row;
}
于 2008-10-02T00:24:56.530 回答
8

根据PHP 文档，您应该能够执行以下操作：

$sql = "SELECT * FROM widgets WHERE something='something else'";
foreach ($database->query($sql) as $row) {
   echo $row["widget_name"];
}
于 2008-10-01T22:04:35.793 回答
3

如果您喜欢 foreach 语法，可以使用以下类：

// Wrap a PDOStatement to iterate through all result rows. Uses a 
// local cache to allow rewinding.
class PDOStatementIterator implements Iterator
{
    public
        $stmt,
        $cache,
        $next;

    public function __construct($stmt)
    {
        $this->cache = array();
        $this->stmt = $stmt;
    }

    public function rewind()
    {
        reset($this->cache);
        $this->next();
    }

    public function valid()
    {
        return (FALSE !== $this->next);
    }

    public function current()
    {
        return $this->next[1];
    }

    public function key()
    {
        return $this->next[0];
    }

    public function next()
    {
        // Try to get the next element in our data cache.
        $this->next = each($this->cache);

        // Past the end of the data cache
        if (FALSE === $this->next)
        {
            // Fetch the next row of data
            $row = $this->stmt->fetch(PDO::FETCH_ASSOC);

            // Fetch successful
            if ($row)
            {
                // Add row to data cache
                $this->cache[] = $row;
            }

            $this->next = each($this->cache);
        }
    }

}

然后使用它：

foreach(new PDOStatementIterator($stmt) as $col => $val)
{
    ...
}
于 2013-06-14T06:07:07.043 回答