laravel 雄辩的第一个 where 子句
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Eloquent the first where clause
提问by Yada
I am wondering how Laravel implement eloquent syntax so that the first where clause can be called statically with User::where()
我想知道 Laravel 如何实现 eloquent 语法，以便可以静态调用第一个 where 子句 User::where()
User::where('id', 23)->where('email', $email)->first();
Do they have a public static function where()and a public function where()
他们有一个public static function where()和一个public function where()
回答by Amo
Calling whereon an Eloquent model does involve a little bit of magic that occurs behind the scenes. Firstly, take the example of:
调用whereEloquent 模型确实涉及到一些幕后发生的魔法。首先，举个例子：
User::where('name', ‘Joe')->first;
There's no static wheremethod that exists on the Modelclass that the Userclass extends.
类扩展的类where上不存在静态方法。ModelUser
What happens, is that the PHP magic method __callStaticis called which attempts to then call the wheremethod.
会发生什么，是__callStatic调用PHP 魔术方法，然后尝试调用该where方法。
public static function __callStatic($method, $parameters)
{
$instance = new static;
return call_user_func_array([$instance, $method], $parameters);
}
As there's no explicitly defined user function called where, the next magic PHP method __callwhich is defined in Modelis executed.
由于没有显式定义的用户函数被调用where，下一个__call在Model中定义的魔法 PHP 方法被执行。
public function __call($method, $parameters)
{
if (in_array($method, ['increment', 'decrement'])) {
return call_user_func_array([$this, $method], $parameters);
}
$query = $this->newQuery();
return call_user_func_array([$query, $method], $parameters);
}
The common database related methods become accessible via:
常见的数据库相关方法可通过以下方式访问：
$query = $this->newQuery();
This instantiates a new Eloquent query builder object, and it's on this object that the wheremethod runs.
这会实例化一个新的 Eloquent 查询构建器对象，并且该where方法运行在这个对象上。
So, when you use ```User::where()`` you're actually using:
因此，当您使用 ```User::where()`` 时，您实际上是在使用：
Illuminate\Database\Eloquent\Builder::where()
Take a look at the Builder classto see all of the common Eloquent methods you're used to using, like where(), get(), first(), update(), etc.
看看在生成器类，看看大家的雄辩方法，你习惯使用，比如where()，get()，first()，update()，等。
Laracastshas a great in-depth (paid) video on how Eloquent works behind the scenes, which I recommend.
Laracasts有一个关于 Eloquent如何在幕后工作的深入（付费）视频，我推荐它。
回答by Daan
Well let's find out.
好吧，让我们来了解一下。
When we open a model it extends Modelso let's open that class.
In the class Modelwe find 2 "magic" methods called __call()and __callStatic()
当我们打开一个模型时，它会扩展，Model所以让我们打开那个类。在类中，Model我们找到了 2 个“神奇”的方法，称为__call()和__callStatic()
__call()is triggered when invoking inaccessible methods in an object context.
__call()在对象上下文中调用不可访问的方法时触发。
__callStatic()is triggered when invoking inaccessible methods in a static context.
__callStatic()在静态上下文中调用不可访问的方法时触发。
We also see in class Modelit makes use of the class use Illuminate\Database\Query\Builder as QueryBuilder;
我们也在课堂上看到Model它使用了类use Illuminate\Database\Query\Builder as QueryBuilder;
If we open the Builderclass we find a method called public function where()
如果我们打开这个Builder类，我们会发现一个名为public function where()
So if you call User::whereit calls __callStatic('where', $parameters)from the Modelclass.
因此，如果您调用User::where它，__callStatic('where', $parameters)则从Model类调用它。
I hope this makes sense.
我希望这是有道理的。
