PHP PDO 准备好的语句

PHP PDO prepared statements(PHP PDO 准备好的语句)

问题描述

今天有人告诉我，我真的应该在我的应用程序中使用 PDO 和准备好的语句.虽然我了解这些好处，但我很难理解如何将它们实施到我的工作流程中.除了它使代码更干净这一事实之外，我应该有一个特定的数据库类来容纳我所有准备好的语句，还是应该在每次我想运行查询时创建一个?我发现很难理解什么时候应该使用标准 PDO 查询以及什么时候应该使用准备好的语句.任何示例、提示或教程链接将不胜感激.

I was told today that I should really be using PDO and prepared statements in my application. Whilst I understand the benefits, I am struggling to understand how I implement them into my workflow. Aside from the fact that it makes code much cleaner, should I have a specific database class which houses all my prepared statements or should I create one each time I want to run a query? I'm finding it very hard to understand when I should use a standard PDO query and when I should use a prepared statement. Any examples, tips or tutorial links would be greatly appreciated.

推荐答案

pdo::prepare() 文档.

我已将它们包含在此处并进行了一些简化.

I have included them here and simplified them a bit.

这个使用 ? 参数.$dbh 基本上是一个 PDO 对象.而您正在做的是将值 150 和 'red' 分别放入第一个和第二个问号.

This one uses ? parameters. $dbh is basically a PDO object. And what you are doing is putting the values 150 and 'red' into the first and second question mark respectively.

/* Execute a prepared statement by passing an array of values */
$sth = $dbh->prepare('SELECT name, colour, calories
                      FROM fruit
                      WHERE calories < ? AND colour = ?');

$sth->execute(array(150, 'red'));

$red = $sth->fetchAll();

这个使用命名参数，有点复杂.

This one uses named parameters and is a bit more complex.

/* Execute a prepared statement by passing an array of values */
$sql = 'SELECT name, colour, calories
        FROM fruit
        WHERE calories < :calories AND colour = :colour';

$sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150, ':colour' => 'red'));

$red = $sth->fetchAll();

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