Laravel基础使用Eloquent ORM操作数据库之查询【一】

雨点打透心脏的1/2处 2022-03-27 02:57 447阅读 0赞

**laravel Eloquent ORM 文档:**[https://laravel-china.org/docs/laravel/5.5/eloquent/1332][https_laravel-china.org_docs_laravel_5.5_eloquent_1332]

**实战项目的话 在我的博客Laravel使用ORM操作数据库增删改查有:**[https://blog.csdn.net/qq\_42611547/article/details/86313955][https_blog.csdn.net_qq_42611547_article_details_86313955]

先创建模型

<?php
    
    namespace App;
    
    use Illuminate\Database\Eloquent\Model;
    
    
    class Vote extends Model
    {
    	//指定表名
    	protected $table = 'Kcb';
    	//指定主键
        protected $primaryKey = 'id';
    
       //时间变成fales
        public $timestamps=false;
    }
    
    
    
    ?>

<?php
    namespace App\Http\Controllers;
    use App\Kcb;
    use Illuminate\Support\Facades\DB;
    class KcbController extends Controller
    {
        public function ormselect()
        {
            //查询所有记录  all()
            $kcbs = Kcb::all();
            //根据主键查询  find()
            $kcbs = Kcb::find(1);
            //根据主键查询，没查到则报错  findorfail()
            $kcbs = Kcb::findorfail(2);
            //使用查询构造器:
            //查询所有记录  get()
            $kcbs =  Kcb::get();
            //查询第一条符合条件的记录
            $kcbs =  Kcb::where('id','>','1')
                ->orderBy('branch','desc')
                ->first();
            print_r($kcbs);
            //使用chunk每次查询指定条数的记录
            echo '<pre>';
            Kcb::chunk(2,function ($kcbs){
                var_dump($kcbs);
            });
            //查询构造器的聚合函数
            //计数
            $num = Kcb::count();
            var_dump($num);
            //最大值
            $max = Kcb::where('id','>','0')->max('branch');
            var_dump($max);
        }
    }

[https_laravel-china.org_docs_laravel_5.5_eloquent_1332]: https://laravel-china.org/docs/laravel/5.5/eloquent/1332
[https_blog.csdn.net_qq_42611547_article_details_86313955]: https://blog.csdn.net/qq_42611547/article/details/86313955