我可以停止CakePHP获取查询的所有行吗？ [英] Can I stop CakePHP fetching all rows for a query?

问题描述

我使用CakePHP与$ modelName-> find（...）
调用选择相当多的行（可能是数百）

I'm using CakePHP with $modelName->find(...) calls to select quite a number of rows (could be hundreds)

通常，在PHP / MySQL中，这当然不是一个问题，因为你在一个while循环中获取它们。
但是，CakePHP将所有行加载到一个数组中，该数组耗尽内存
limit。

Normally, in PHP/MySQL of course this wouldn't be a problem, as you fetch them in a while loop. But, CakePHP loads all rows in to an array which exhausts the memory limit.

有一种方法可以使用$ modelName-> find（...）构造，但是返回一个
迭代器来按需获取每一行？

Is there a way to use the $modelName->find(...) constructs but return an iterator to fetch each row on demand?

谢谢，
David

Thanks, David

推荐答案

不，开箱即用的Cake PHP（和一般的ActiveRecord）不支持迭代这样的结果集。如果你有一个用例，你实际需要所有表的记录，你可能最好使用原始SQL。 （或重新思考你的用例）。

No, out of the box Cake PHP (and ActiveRecord in general) doesn't support iterating over a result set like that. If you have a use case where you actually need all the records of a table, you're probably better off using raw SQL. (or rethinking your use case).

你也可以（并且可能已经考虑过）使用某种偏移，然后调用 - >找到多次。如果采用这种方法，不要忘记通过某个字段对结果集进行排序以确保确定性结果。当您离开ORDER BY时，数据库似乎只返回排序的行。我没有亲自尝试过，从多个查询的角度来看，它似乎效率低下，但它是值得尝试的。

You could also (and have likely already thought to) use an offset of some kind, and call ->find multiple times. If you take this approach don't forget to order your result set by some field to ensure a deterministic result. Databases only seem to return sorted rows when you leave an ORDER BY off. I haven't personally tried this, and it seems inefficient from a multiple queries standpoint, but it's something worth trying.

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