問題描述

我目前正在通過切換到 PDO 來更新我的應(yīng)用.我有以下代碼:

I'm currently updating my app by switching to PDO. I have the following code:

$stmt = $db->prepare("select * from `product` where productid in (:productidLst)");
$stmt->bindParam(":productidLst",$productidLst, PDO::PARAM_INT);
$stmt->execute();

在上面的代碼之后，var $productidLst 是 1,2 我想使用 PDO 等價物:

The var $productidLst is 1,2 after the above code I would like to use the PDO equivalent of this:

while($rs=mysql_fetch_assoc($res)){
    $rs['qty']=$_SESSION['basket'][$rs['productid']];
    $rs['total'] += $rs['qty']*$rs['price'];
    $total += $rs['total'];
    $a[] = $rs;
}

我嘗試了多種組合，但都沒有成功，因此將不勝感激(在第二個代碼塊中，$res 是 sql).其次，我已將參數(shù) $productidLst 設(shè)置為 INT 這是正確的還是應(yīng)該是字符串?

I have tried numerous combinations but not been successful so any help with this would be appreciated (in the 2nd code block $res was the sql). Secondly I have set the Parameter $productidLst to INT is this correct or should it be a string?

------------更新 1---------------------------------------------------

--------------------UPDATE 1----------------------------------------------------

我嘗試了以下代碼:

$stmt = $db->prepare("select * from `product` where productid in (:productidLst)");
foreach ($stmt->execute(array(':productidLst' => $productidLst)) as $row) 
{
    $total += $row['total'];
}

返回:為 foreach() 錯誤提供的無效參數(shù)

Which returns: Invalid argument supplied for foreach() error

推薦答案

PHP 手冊中的標(biāo)準(zhǔn)文檔通常很有幫助.PHP手冊中有一個用PDO執(zhí)行for循環(huán)的例子，PDO詳情.

The standard documentation in the PHP manual is usually pretty helpful. There is an example of executing a for loop with PDO in the PHP manual, PDO Details.

function getFruit($conn) {
    $sql = 'SELECT name, color, calories FROM fruit ORDER BY name';
    foreach ($conn->query($sql) as $row) {
        print $row['name'] . "	";
        print $row['color'] . "	";
        print $row['calories'] . "
";
    }
}

通過一些更改，該示例可以使用準(zhǔn)備好的語句.

With a few changes, the example can be made to use a prepared statement.

function getFruit($conn) {
    $query = $conn->prepare('SELECT name, color, calories FROM fruit WHERE kind=:kind ORDER BY name');
    $query->execute(array(':kind' => 'drupe'));
    // alternatively you could use PDOStatement::fetchAll() and get rid of the loop
    // this is dependent upon the design of your app
    foreach ($query as $row) {
        print $row['name'] . "	";
        print $row['color'] . "	";
        print $row['calories'] . "
";
    }
}

您還可以使用 while 循環(huán)和 PDOStatement::fetch 獲取每一行.

You can also use a while loop and PDOStatement::fetch to get each row.

function getFruit($conn) {
    $query = $conn->prepare('SELECT name, color, calories FROM fruit WHERE kind=:kind ORDER BY name');
    $query->execute(array(':kind' => 'drupe'));
    // alternatively you could use PDOStatement::fetchAll() and get rid of the loop
    // this is dependent upon the design of your app
    while ($row = $query->fetch(PDO::FETCH_ASSOC)) {
        print $row['name'] . "	";
        print $row['color'] . "	";
        print $row['calories'] . "
";
    }
}

PHP 手冊在提供創(chuàng)建后兩個版本所需的所有信息方面仍然非常有用.

The PHP manual remains quite helpful in providing all the necessary information to create the latter two versions.

上一個版本的解釋:假設(shè) $conn 是一個有效的 PDO 對象.$conn->prepare($sql) 返回一個 PDOStatement 對象如果成功，false 失敗 OR 基于您的錯誤處理的異常.因此，假設(shè)成功，我們希望實際從對象中獲取數(shù)據(jù).我們可以使用 $query->fetch() 在循環(huán)或 $query->fetchAll() 獲取依賴于您的應(yīng)用的數(shù)據(jù).傳入類常量 PDO::FETCH_ASSOC 將返回一個數(shù)據(jù)關(guān)聯(lián)數(shù)組.

Explanation of the last version: assuming $conn is a valid PDO object. $conn->prepare($sql) returns a PDOStatement object if successful, false on failure OR an exception based on your error handling. So, assuming success we would want to actually get the data from the object. We can use $query->fetch() in a loop or $query->fetchAll() to get the data dependent upon your app. Passing in the class constant PDO::FETCH_ASSOC will return, you guessed it, an associative array of data.

在功能上，foreach 和 while 實現(xiàn)是等效的.從概念上講，foreach 更合適，因為 while 循環(huán)具有在靜態(tài)條件成立時循環(huán)的含義，而 foreach 循環(huán)遍歷 a 的元素收藏.閱讀一段時間之間的差異PHP 中的循環(huán)和 for 循環(huán)?" 部分故事.

Functionally, the foreach and while implementations are equivalent. Conceptually, a foreach is more appropriate, as a while loop has connotations of looping while a static condition holds, whereas foreach loops over elements of a collection. Read "Differences between a while loop and a for loop in PHP?" for part of the story.

請務(wù)必閱讀 關(guān)于 PDO 的 php.net 參考

這篇關(guān)于將 PHP while 循環(huán)轉(zhuǎn)換為使用 PDO的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！