PDO 准备好的语句 - 参数名称中的冒号是做什么用的? [英] PDO prepared statement - what are colons in parameter names used for?

问题描述

我看过很多文章在使用 PDO 时在命名参数前使用冒号 (:)，还有一些文章不使用冒号.我会尽快不使用冒号，只是因为它少了一个按键并且更容易阅读.

I've seen many articles using colons (:) in front of named parameters when using PDO, and a couple that do not use the colon. I'd just as soon not use the colon, simply because it's one less keystroke and slightly easier to read.

它似乎对我来说工作正常，但我很好奇在使用冒号时是否遗漏了一些重要的东西?

It seems to be working fine for me, but I'm curious if there is something important that I'm missing when it comes to the use of colons?

例如，这很好用:

function insertRecord ($conn, $column1, $comumn2) {
    try {
        $insertRecord = $conn->prepare('INSERT INTO Table1 (column1, column2)
        VALUES(:column1, :column2)');
        $insertRecord->execute(array(
                'column1' => $column1,
                'column2' => $column2
            ));
    }
    catch(PDOException $e) {
        echo $e->getMessage();
    }
}

与大多数开发人员使用它相反，它也有效:

As opposed to most developers using this, which also works:

function insertRecord ($conn, $column1, $comumn2) {
    try {
        $insertRecord = $conn->prepare('INSERT INTO Table1 (column1, column2)
        VALUES(:column1, :column2)');
        $insertRecord->execute(array(
                ':column1' => $column1,
                ':column2' => $column2
            ));
    }
    catch(PDOException $e) {
        echo $e->getMessage();
    }
}

注意 execute 语句参数中的冒号.

Notice the colons in the execute statement parameters.

我想了解冒号的用途.

推荐答案

SQL 语句中需要冒号，以指示哪些标识符是占位符.

Colons are required in the SQL statement, to indicate which identifiers are placeholders.

execute() 或 bindParam() 调用中的冒号是可选的.文档指定了它们，但实现足够聪明，可以弄清楚如果你不考虑它们是什么意思(你还能指什么?).

Colons in the execute() or bindParam() calls are optional. The documentation specifies them, but the implementation is clever enough to figure out what you mean if you leave them out (what else could you mean?).

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