这意味着什么？

发布于 2024-10-10 19:51:10 字数 468 浏览 3 评论 0原文

我在谷歌搜索时在一些代码示例中发现了这一点：

$sql = 'INSERT INTO users (username,passwordHash) VALUES (?,?)';

这对我来说是新的，但我猜它是一种替代方法，相当于

$sql = "INSERT INTO users (username,passwordHash) VALUES ($username,$passwordHash)";`

或

$sql = 'INSERT INTO users (username,passwordHash) VALUES (' . $username . ',' . $passwordHash . ')';`

是否正确？这是一个实际的 PHP 语法，还是他只是想简化他的示例？

谢谢大家的反馈

原文

I found this in some code examples while googling :

$sql = 'INSERT INTO users (username,passwordHash) VALUES (?,?)';

it's new to me, but I would guess that it a substitution method and equivalent to

$sql = "INSERT INTO users (username,passwordHash) VALUES ($username,$passwordHash)";`

$sql = 'INSERT INTO users (username,passwordHash) VALUES (' . $username . ',' . $passwordHash . ')';`

would that be correct? Is it an actual PHP syntax, or was he just trying to simplify his example?

Thanks for the feedback, folks

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

久光 2024-10-17 19:51:10

这在准备好的语句中很常见。 ? 仅用作占位符，如下面的 PHP 文档所示：

$stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value) VALUES (?, ?)");
$stmt->bindParam(1, $name);
$stmt->bindParam(2, $value);

// insert one row
$name = 'one';
$value = 1;
$stmt->execute();

// insert another row with different values
$name = 'two';
$value = 2;
$stmt->execute();

This is pretty common in prepared statements. The ? merely serves as a placeholder, as seen below from the PHP documentation:

$stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value) VALUES (?, ?)");
$stmt->bindParam(1, $name);
$stmt->bindParam(2, $value);

// insert one row
$name = 'one';
$value = 1;
$stmt->execute();

// insert another row with different values
$name = 'two';
$value = 2;
$stmt->execute();

回复收藏 0 原文