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深入理解 Laravel Eloquent（二）——中间操作流（Builder）
本篇教程是该系列教材的第二篇，将主要讲述 Eloquent 中中间操作流的概念。中间操作流是我自己总结并翻译的概念，支撑该功能的类位于 Illuminate\Database\Eloquent\Builder，此概念对于新手入门有很大帮助，但是官方文档没有相关概念和解释。
来自 https://lvwenhan.com/laravel/422.html
什么是“中间操作流”（Builder）
Builder 这个单词可以直译成构造器，但是“中间操作流”更容易理解，因为数据库操作大部分时候都是链式操作的。
中间操作流，请看代码：
Article::where('id', '>', 10)->where('id', '<', 20)->orderBy('updated_at', 'desc')->get();
这段代码的 `::where()->where()->orderBy()` 就是中间操作流。中间操作流用面向对象的方法来理解，可以总结成一句话：
创建一个对象，并不断修改它的属性，最后用一个操作来触发数据库操作。
但是，我们都知道，如果直接用 :: 来访问某个 function，无论这个 function 是否为 static，构造函数 __construct() 都不会被调用，那么创建对象是如何实现的呢？请看：https://github.com/illuminate/database/blob/master/Eloquent/Model.php#L3354
如何找到中间操作流的蛛丝马迹
中间操作流这个东西，文档里几乎没有任何有价值的信息，那么，我们该怎么找出这个玩意儿呢？很简单，使用以下代码：
$builder = Article::where('title', "我是标题")->title;
然后你就会看到下面的错误：
为什么会出现错误？因为 `Article::where()` 了之后依然是 `Builder` 对象，还不是 `Article` 对象，不能直接取 `title`。
“终结者”方法
所谓 “终结者” 方法，指的是在 N 个中间操作流方法对某个 Eloquent 对象进行加工以后，触发最终的数据库查询操作，得到返回值。
`first()` `get()` `paginate()` `count()` `delete()` 是用的比较多的一些 “终结者” 方法，他们会在中间操作流的最后出现，把 SQL 打给数据库，得到返回数据，经过加工返回一个 Article 对象或者一群 Article 对象的集合。
复杂用法示例
Article::where('id', '>', '100')->where('id', '<', '200')->orWhere('top', 1)->belongsToCategory()->where('category_level', '>', '1')->paginate(10);
小菜鸟
2016-04-20 11:46
大神你好，请问在eloquent里，我想执行where in这种语句应该如何构造
select * from table where id in ('id,id,id,')
原型是这种的，望赐教！
2016-04-20 11:46
大神你好，请问在eloquent里，我想执行where in这种语句应该如何构造
select * from table where id in ('id,id,id,')
原型是这种的，望赐教！
祥子
2015-09-30 11:49
2015-09-30 11:49
$instance = new static;
return call_user_func_array([$instance, $method], $parameters);
new static 是PHP5.5的语法吧。
return call_user_func_array([$instance, $method], $parameters);
new static 是PHP5.5的语法吧。
simon
2015-05-29 16:04
2015-05-29 16:04
恕我冒昧，提个建议, builder的直接翻译“构造器”已经足够说明一切，您的中间操作流，会使人家更加混淆和云里雾里。构造器负责把SQL操作需要提供的各个组成部分收集在一起后，最终生成实际执行的SQL 语句，就这么简单。链式操作只是一个简便的写法，假设有个buider对象，那么
buider->where()->group()->orderby()等价于：
builder->where(“age>30");
builder->group("gender");
builder->orderby("age");
最后的操作，假如有增删改查对应的接口函数为insert(), delete(), update(), select(),那么这些接口会使用buider收集到的参数生成对应的SQL语句.
buider->where()->group()->orderby()等价于：
builder->where(“age>30");
builder->group("gender");
builder->orderby("age");
最后的操作，假如有增删改查对应的接口函数为insert(), delete(), update(), select(),那么这些接口会使用buider收集到的参数生成对应的SQL语句.
azxkill
2015-04-10 23:28
2015-04-10 23:28
楼主你好,今天装了个xdebug.结果运行laravel直接apache cpu 100% ,然后就页面超时了.我运行TP等其它项目都没事,关掉xdebug再打开laravel就正常了,请问这是什么情况啊.
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1/1 FatalErrorException in compiled.php line 8952: Maximum execution time of 30 seconds exceeded
in compiled.php line 8952
at FatalErrorException->__construct('message' => ''Maximum execution time of 30 seconds exceeded'', 'code' => '1', 'severity' => '0', 'filename' => ''/usr/local/apache2.4.10/htdocs/myLaravel/vendor/compiled.php'', 'lineno' => '8952', 'traceOffset' => '0', 'traceArgs' => '???') in compiled.php line 1743
at HandleExceptions->fatalExceptionFromError('error' => 'array ('type' => 1, 'message' => 'Maximum execution time of 30 seconds exceeded', 'file' => '/usr/local/apache2.4.10/htdocs/myLaravel/vendor/compiled.php', 'line' => 8952)', 'traceOffset' => '0') in compiled.php line 1738
at HandleExceptions->handleShutdown() in compiled.php line 0
at call_user_func:{/usr/local/apache2.4.10/htdocs/myLaravel/vendor/compiled.php:8952}('class Closure { public $static = array ('instance' => class App\Http\Controllers\Admin\AdminHomeController { protected $middleware = array (); protected $beforeFilters = array (); protected $afterFilters = array () }, 'route' => class Illuminate\Routing\Route { protected $uri = 'admin'; protected $methods = array (0 => 'GET', 1 => 'HEAD'); protected $action = array ('middleware' => 'auth', 'uses' => 'App\\Http\\Controllers\\Admin\\AdminHomeController@index', 'controller' => 'App\\Http\\Controllers\\Admin\\AdminHomeController@index', 'namespace' => 'App\\Http\\Controllers\\Admin', 'prefix' => '/admin', 'where' => array ()); protected $defaults = array (); protected $wheres = array (); protected $parameters = array (); protected $parameterNames = array (); protected $compiled = class Symfony\Component\Routing\CompiledRoute { private $variables = array (); private $tokens = array (0 => array (0 => 'text', 1 => '/admin')); private $staticPrefix = '/admin'; private $regex = '#^/admin$#s'; private $pathVariables = array (); private $hostVariables = array (); private $hostRegex = NULL; private $hostTokens = array () }; protected $container = ... }, 'method' => 'index'); public $this = class Illuminate\Routing\ControllerDispatcher { protected $router = ...; protected $container = ... }; public $parameter = array ('$request' => '<required>') }', '...') in compiled.php line 8952
at Pipeline->Illuminate\Pipeline\{closure}('passable' => '...') in compiled.php line 8935
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1/1 FatalErrorException in compiled.php line 8952: Maximum execution time of 30 seconds exceeded
in compiled.php line 8952
at FatalErrorException->__construct('message' => ''Maximum execution time of 30 seconds exceeded'', 'code' => '1', 'severity' => '0', 'filename' => ''/usr/local/apache2.4.10/htdocs/myLaravel/vendor/compiled.php'', 'lineno' => '8952', 'traceOffset' => '0', 'traceArgs' => '???') in compiled.php line 1743
at HandleExceptions->fatalExceptionFromError('error' => 'array ('type' => 1, 'message' => 'Maximum execution time of 30 seconds exceeded', 'file' => '/usr/local/apache2.4.10/htdocs/myLaravel/vendor/compiled.php', 'line' => 8952)', 'traceOffset' => '0') in compiled.php line 1738
at HandleExceptions->handleShutdown() in compiled.php line 0
at call_user_func:{/usr/local/apache2.4.10/htdocs/myLaravel/vendor/compiled.php:8952}('class Closure { public $static = array ('instance' => class App\Http\Controllers\Admin\AdminHomeController { protected $middleware = array (); protected $beforeFilters = array (); protected $afterFilters = array () }, 'route' => class Illuminate\Routing\Route { protected $uri = 'admin'; protected $methods = array (0 => 'GET', 1 => 'HEAD'); protected $action = array ('middleware' => 'auth', 'uses' => 'App\\Http\\Controllers\\Admin\\AdminHomeController@index', 'controller' => 'App\\Http\\Controllers\\Admin\\AdminHomeController@index', 'namespace' => 'App\\Http\\Controllers\\Admin', 'prefix' => '/admin', 'where' => array ()); protected $defaults = array (); protected $wheres = array (); protected $parameters = array (); protected $parameterNames = array (); protected $compiled = class Symfony\Component\Routing\CompiledRoute { private $variables = array (); private $tokens = array (0 => array (0 => 'text', 1 => '/admin')); private $staticPrefix = '/admin'; private $regex = '#^/admin$#s'; private $pathVariables = array (); private $hostVariables = array (); private $hostRegex = NULL; private $hostTokens = array () }; protected $container = ... }, 'method' => 'index'); public $this = class Illuminate\Routing\ControllerDispatcher { protected $router = ...; protected $container = ... }; public $parameter = array ('$request' => '<required>') }', '...') in compiled.php line 8952
at Pipeline->Illuminate\Pipeline\{closure}('passable' => '...') in compiled.php line 8935
普通分类:
2016-05-01 23:28