2  

Neither.

Returning false to indicate error is fine at a very low level, but there should a layer between your low-level queries and your application code which inspects the return value and throws an exception on false. The top-level controller which invokes your code should be handling those exceptions (which aren't caught earlier) and displaying a user-friendly error page in production, or dumping debugging information in development, while logging the error.

返回false表示错误在非常低的级别上很好,但是在低级查询和应用程序代码之间应该有一层检查返回值并在false时抛出异常。调用代码的顶级控制器应该处理这些异常(之前没有捕获)并在生产中显示用户友好的错误页面,或在开发过程中转储调试信息,同时记录错误。

There is absolutely no way you should be doing a three-way if/elseif/else branch in your application to inspect the return values of every single database query. This is an incredibly dated way of checking for errors.

绝对没有办法在应用程序中执行三向if / elseif / else分支来检查每个数据库查询的返回值。这是一种检查错误的难以置信的过时方法。

Throw exceptions, and you can use your first form (if ($someVar)) or, better yet:

抛出异常,你可以使用你的第一个表单(if($ someVar)),或者更好的是:

foreach ($this->someFunction() as $key => $row) {


}

1  

http://php.net/manual/en/types.comparisons.php

An empty array evaluates to false. An array with values evaluates to true (even if all values would individually evaluate to false).

空数组的计算结果为false。值的数组计算结果为true(即使所有值都单独计算为false)。

You can also check if (empty($array)) but it is redundant to do so unless you are concerned about the array variable not being set.

您还可以检查是否为空($ array),但这样做是多余的,除非您担心未设置数组变量。

Finally, if the array is empty, $array == false is true, but $array === false is not.

最后,如果数组为空,$ array == false为true,但$ array === false不是。

1  

According to the documentation on type comparisons, your first method is completely acceptable. An empty array will always evaluate to FALSE.

根据类型比较的文档,您的第一种方法是完全可以接受的。空数组总是计算为FALSE。

Documentation: http://php.net/manual/en/types.comparisons.php

That said, you may choose to handle no results and errors differently, e.g. logging the error message to a server log. In this case, you may want multiple if() conditions.

也就是说,您可以选择不同地处理任何结果和错误,例如将错误消息记录到服务器日志。在这种情况下,您可能需要多个if()条件。

0  

Neither. Test for all three cases:

都不是。测试所有三种情况:

if (false === $result) {
    die('There is an error!');
} elseif (empty($result)) {
    die('No results found');
}

foreach ($result as $foo) { ... }

If you really want to test for just two, then remember that foreach will work in an empty array. So, this will work:

如果你真的只想测试两个,那么请记住foreach将在一个空数组中工作。所以,这将工作:

if (false === $result) {
    die('There was an error!');
}

foreach ($result as $foo) { ... }

Or:

if (false === $result) {
    echo 'There was an error!';
} else {
    foreach ($result as $foo) { ... }
}

These last examples will simply give an empty page when the $result is an empty array. The first example will say that there are no results.

当$ result为空数组时,这些最后的示例将简单地给出一个空页面。第一个例子说没有结果。