问题描述
通常，在许多框架中，您可以找到使用查询构建器创建查询的示例.你经常会看到:
Commonly, in a lot of frameworks, you can find examples of creating a query using the query builder. Often you will see:
$query->select('field');
$query->from('entity');
但是，在某些框架中你也可以这样做
However, in some frameworks you can also do it like this
$object->select('field')
->from('table')
->where( new Object_Evaluate('x') )
->limit(1)
->order('x', 'ASC');
您实际上是如何制作这种链条的?
How do you actually do this kinds of chains?
推荐答案
这叫做 Fluent Interface -- 该页面上有一个 PHP 示例.
This is called Fluent Interface -- there is an example in PHP on that page.
基本思想是该类的每个方法(您希望能够链接) 必须返回 $this -- 这使得调用其他方法成为可能返回的 $this 上同一个类的方法.
The basic idea is that each method (that you want to be able to chain) of the class has to return $this -- which makes possible to call other methods of that same class on the returned $this.
当然，每个方法都可以访问类的当前实例的属性——这意味着每个方法都可以向当前实例添加一些信息".
And, of course, each method has access to the properties of the current instance of the class -- which means each method can "add some information" to the current instance.
这篇关于方法链 PHP OOP的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！