Laravel框架Eloquent ORM简介、模型建立及查询数据操作详解
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2023-11-04 21:08:34
本文实例讲述了laravel框架eloquent orm简介、模型建立及查询数据操作。分享给大家供大家参考,具体如下:
注:以下知识点可能有不全面之处,望见谅
no.1el...
本文实例讲述了laravel框架eloquent orm简介、模型建立及查询数据操作。分享给大家供大家参考,具体如下:
注:以下知识点可能有不全面之处,望见谅
no.1eloquent orm简介
laravel所自带的eloquent orm是一个优美、简洁的activerecord实现,用来实现数据库操作
每个数据表都有与之相对应的“模型(model)”用于和数据交互
no.2模型的建立
最基础的模型代码如下:
namespace app; use illuminate\database\eloquent\model; class student extends model { //指定表名 protected $table = 'student'; //指定id protected $primarykey = 'id'; }
将他创建于app目录下,命名为student.php
no.3查询数据
首先在查询之前,我先让你们看一下我的数据库
数据如上,然后查询
1.all方式
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $students = student::all(); dd($students); } }
显示数据库里的所有数据
2.find方式
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $students = student::find(1); dd($students); } }
查找指定数据
3.findorfail方式
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $students = student::findorfail(1); dd($students); } }
如果他没查到指定的数据,那么他会报错,而find若是没有查到该函数,只会弹出一个null
4.查询构造器的使用
- 1.get方式使用
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $students = student::get(); dd($students); } }
他会得到一个完整的数据信息,和原本的意义没有区别
- 2.first方式使用
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::where('id','>',1) ->orderby('age','desc') ->first(); dd($student); } }
当id大于一的时候,获取一个最大值的age
- 3.where方式使用
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::where('id','>',1) ->get(); dd($student); } }
- 4.chunk方式使用
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::chunck(2,function($student){ var_dump($student); }); } }
5.聚合函数的使用
- 1.count函数
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::count(); dd($student); } }
- 2.max函数
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::max('age'); dd($student); } }
- 3.min函数
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::min('age'); dd($student); } }
- 4.avg函数
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::avg('age'); dd($student); } }
- 5.sum函数
代码如下:
namespace app\http\controllers; use app\student; use illuminate\support\facades\db; class studentcontroller extends controller { public function orm1() { $student = student::sum('age'); dd($student); } }