php - 如何防止 MySQL 使用 PDO 更新带有空字符串的列

Question

我有一个确切的问题 How do I prevent MySQL from updating column with an empty string

然而，唯一的不同是我将其应用于 PDO 而不是传统的 MySQL。

我已经按照关于添加 IF 语句以检查长度是否为 0 的问题的最佳答案进行操作。这似乎不适用于 PDO，但是因为表格和网页输出中没有发生更新:Array ( [0] => HY093 [1] => [2] => ) 1。请注意，我正在通过绑定(bind)函数使用准备好的语句。

我的包含 IF 语句的 PHP 代码:

    <?php
$pdo=new PDO("mysql:dbname=createyo_TestDatabase;host=localhost","createyo_james","password");

$statement=$pdo->prepare(
"UPDATE `Users` 
SET `EditIDs` = IF(LENGTH(':EditID')=0, EditIDs, ':EditID'), 
`ArticleIDs` = IF(LENGTH(':ArticleID')=0, ArticleIDs, ':ArticleID'),
`Reputation` = IF(LENGTH(':Reputation')=0, Reputation, ':Reputation'),
`VotedUpArticleIDs` = IF(LENGTH(':VotedUpArticleID')=0, VotedUpArticleIDs, ':VotedUpArticleID'),
`VotedUpEditIDs` = IF(LENGTH(':VotedUpEditID')=0, VotedUpEditIDs, ':VotedUpEditID'),
`VotedDownArticleIDs` = IF(LENGTH(':VotedDownArticleID')=0, VotedDownArticleIDs, ':VotedDownArticleID'),
`VotedDownEditIDs` = IF(LENGTH(':VotedDownEditID')=0, VotedDownEditIDs, ':VotedDownEditID'),
WHERE `UserID` = :UserID");

$statement->bindValue(':EditID', (string) trim($_GET['EditID']), PDO::PARAM_STR);
$statement->bindValue(':ArticleID', (string) trim($_GET['ArticleID']), PDO::PARAM_STR);
$statement->bindValue(':Reputation', (string) trim($_GET['Reputation']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpArticleID', (string) trim($_GET['VotedUpArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpEditID', (string) trim($_GET['VotedUpEditID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownArticleID', (string) trim($_GET['VotedDownArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownEditID', (string) trim($_GET['VotedDownEditID']), PDO::PARAM_STR);

    $statement->bindValue(':UserID', (string) trim($_GET['UserID']), PDO::PARAM_STR);

    $statement->execute() or die(print_r($statement->errorInfo()));
$results=$statement->fetchAll(PDO::FETCH_ASSOC);
$json=json_encode($results);
print $json;
?>

编辑

我现在收到语法错误:您的 SQL 语法有误；检查与您的 MySQL 服务器版本对应的手册，了解在第 9 行的“WHERE UserID = '1234''附近使用的正确语法。我无法理解此错误。

新的 PHP 代码:

$statement=$pdo->prepare(
"UPDATE `Users` 
SET `EditIDs` = IF(LENGTH(:EditID)=0, EditIDs, :EditID1), 
`ArticleIDs` = IF(LENGTH(:ArticleID)=0, ArticleIDs, :ArticleID1),
`Reputation` = IF(LENGTH(:Reputation)=0, Reputation, :Reputation1),
`VotedUpArticleIDs` = IF(LENGTH(:VotedUpArticleID)=0, VotedUpArticleIDs, :VotedUpArticleID1),
`VotedUpEditIDs` = IF(LENGTH(:VotedUpEditID)=0, VotedUpEditIDs, :VotedUpEditID1),
`VotedDownArticleIDs` = IF(LENGTH(:VotedDownArticleID)=0, VotedDownArticleIDs, :VotedDownArticleID1),
`VotedDownEditIDs` = IF(LENGTH(:VotedDownEditID)=0, VotedDownEditIDs, :VotedDownEditID1),
WHERE `UserID` = :UserID");
$statement->bindValue(':EditID', (string) trim($_GET['EditID']), PDO::PARAM_STR);
$statement->bindValue(':ArticleID', (string) trim($_GET['ArticleID']), PDO::PARAM_STR);
    $statement->bindValue(':Reputation', (string) trim($_GET['Reputation']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpArticleID', (string) trim($_GET['VotedUpArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpEditID', (string) trim($_GET['VotedUpEditID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownArticleID', (string) trim($_GET['VotedDownArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownEditID', (string) trim($_GET['VotedDownEditID']), PDO::PARAM_STR);

$statement->bindValue(':EditID1', (string) trim($_GET['EditID']), PDO::PARAM_STR);
$statement->bindValue(':ArticleID1', (string) trim($_GET['ArticleID']), PDO::PARAM_STR);
$statement->bindValue(':Reputation1', (string) trim($_GET['Reputation']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpArticleID1', (string) trim($_GET['VotedUpArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpEditID1', (string) trim($_GET['VotedUpEditID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownArticleID1', (string) trim($_GET['VotedDownArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownEditID1', (string) trim($_GET['VotedDownEditID']), PDO::PARAM_STR);

Answer 1

在 SQL 中，您不应该将 :placeholder 放在引号内。这使它们成为文字字符串，因此它们不会被绑定(bind)参数替换。

$statement=$pdo->prepare(
"UPDATE `Users` 
SET `EditIDs` = IF(LENGTH(:EditID)=0, EditIDs, :EditID), 
`ArticleIDs` = IF(LENGTH(:ArticleID)=0, ArticleIDs, :ArticleID),
`Reputation` = IF(LENGTH(:Reputation)=0, Reputation, :Reputation),
`VotedUpArticleIDs` = IF(LENGTH(:VotedUpArticleID)=0, VotedUpArticleIDs, :VotedUpArticleID),
`VotedUpEditIDs` = IF(LENGTH(:VotedUpEditID)=0, VotedUpEditIDs, :VotedUpEditID),
`VotedDownArticleIDs` = IF(LENGTH(:VotedDownArticleID)=0, VotedDownArticleIDs, :VotedDownArticleID),
`VotedDownEditIDs` = IF(LENGTH(:VotedDownEditID)=0, VotedDownEditIDs, :VotedDownEditID),
WHERE `UserID` = :UserID");

但是，您也不允许在同一查询中多次使用相同的 :placeholder。因此，您需要为重复的占位符指定不同的名称。

$statement=$pdo->prepare(
"UPDATE `Users` 
SET `EditIDs` = IF(LENGTH(:EditID)=0, EditIDs, :EditID1), 
`ArticleIDs` = IF(LENGTH(:ArticleID)=0, ArticleIDs, :ArticleID1),
`Reputation` = IF(LENGTH(:Reputation)=0, Reputation, :Reputation1),
`VotedUpArticleIDs` = IF(LENGTH(:VotedUpArticleID)=0, VotedUpArticleIDs, :VotedUpArticleID1),
`VotedUpEditIDs` = IF(LENGTH(:VotedUpEditID)=0, VotedUpEditIDs, :VotedUpEditID1),
`VotedDownArticleIDs` = IF(LENGTH(:VotedDownArticleID)=0, VotedDownArticleIDs, :VotedDownArticleID1),
`VotedDownEditIDs` = IF(LENGTH(:VotedDownEditID)=0, VotedDownEditIDs, :VotedDownEditID1)
WHERE `UserID` = :UserID");

然后你必须绑定(bind)所有额外的参数:

$statement->bindValue(':EditID1', (string) trim($_GET['EditID']), PDO::PARAM_STR);
$statement->bindValue(':ArticleID1', (string) trim($_GET['ArticleID']), PDO::PARAM_STR);
$statement->bindValue(':Reputation', (string) trim($_GET['Reputation']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpArticleID1', (string) trim($_GET['VotedUpArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedUpEditID1', (string) trim($_GET['VotedUpEditID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownArticleID1', (string) trim($_GET['VotedDownArticleID']), PDO::PARAM_STR);
$statement->bindValue(':VotedDownEditID1', (string) trim($_GET['VotedDownEditID']), PDO::PARAM_STR);