php的db类库Eloquent单独使用系列（10）- 远程一对多

程序员文章站 2022-03-06 22:25:47

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create table countries (
  id int(11) NOT NULL AUTO_INCREMENT,
  name varchar(50)  NOT NULL DEFAULT '' COMMENT '国家名称',
  PRIMARY KEY (id)
);


CREATE TABLE users (
  id int(11) NOT NULL AUTO_INCREMENT,
  name varchar(50)  NOT NULL DEFAULT '' COMMENT '用户名称',
  country_id int(11) NOT NULL DEFAULT '0' COMMENT '国家id',
  PRIMARY KEY (id)
);

create table posts (
  id int(11) NOT NULL AUTO_INCREMENT,
  user_id int  NOT NULL DEFAULT '0' COMMENT '用户id',
  title varchar(255) not null default '' comment '文章标题',
  PRIMARY KEY (id)
);

源代码
Country.php 国家模型类

<?php
namespace app\model\ill5;
use \Illuminate\Database\Eloquent\Model;

/**
 * 国家模型类
 */
class Country extends Model 
{
    protected $table = 'countries';
    public $timestamps = false;
    
    /**
     * 获取指定国家的所有文章
     */
    public function posts()
    {
        //当执行这种关联查询时通常 Eloquent 外键规则会被使用，如果你想要自定义该关联关系的外键，
        //可以将它们作为第三个、第四个参数传递给hasManyThrough 方法。第三个参数是中间模型的外键名，
        //第四个参数是最终模型的外键名，第五个参数是本地主键。
        return $this->hasManyThrough('app\model\ill5\Post', 'app\model\ill5\User', 'country_id', 'user_id', 'id');
    }
}

用户模型类User.php

<?php
namespace app\model\ill5;
use \Illuminate\Database\Eloquent\Model;

/**
 * User模型类
 */
class User extends Model 
{
    protected $table = 'users';
    public $timestamps = false;
}

文章模型类

<?php
namespace app\model\ill5;
use \Illuminate\Database\Eloquent\Model;

/**
 * Post模型类
 */
class Post extends Model 
{
    protected $table = 'posts';
    public $timestamps = false;
}

主程序

<?php
namespace app\control;

use Illuminate\Database\Capsule\Manager;
use app\model\ill5\User;
use app\model\ill5\Country;
use app\model\ill5\Post;

class Ill5
{
    /**
     * 主程序。
     */
    public function index() 
    {
        $db = new Manager ();
        $db->addConnection ( [ 
            'driver' => 'mysql',
            'host' => '127.0.0.1',
            'database' => 'test1',
            'username' => 'root',
            'password' => 'root',
            'charset' => 'utf8mb4',
            'collation' => 'utf8mb4_unicode_ci',
            'prefix' => '' 
        ] );
        $db->setAsGlobal ();
        $db->bootEloquent ();
      
        $db::delete('delete from users ');
        $db::delete('delete from posts ');
        $db::delete('delete from countries ');
        
        foreach (range(1,2) as $v) {
            $country = new Country();
            $country->name = '国家'.$v;
            $country->id = $v;
            $country->save (); // 新模型添加
        }
        foreach (range(1,5) as $v) {
            $user = new User ();
            $user->name = '用户'.$v;
            $user->id = $v;
            if ($v< 4) {
                $user->country_id = 1;
            }else {
                $user->country_id = 2;
            }
            $user->save (); // 新模型添加
        }
        foreach (range(1,10) as $v) {
            $post = new Post ();
            $post->title = '文章'.$v;
            $post->id = $v;
            if ($v < 5) {
                $post->user_id = 1;
            }elseif ($v < 9){
                $post->user_id = 2;
            }else  {
                $post->user_id = 5;
            }
            $post->save (); // 新模型添加
        }
        
        echo "<h2>国家1的所有文章</h2>";
        echo Country::find(1)->posts->toJson(JSON_UNESCAPED_UNICODE);
        echo "<br>";
        echo "<h2>国家2的所有文章</h2>";
        echo Country::find(2)->posts->toJson(JSON_UNESCAPED_UNICODE);
        echo "<br>";
        
        echo '<br>all ok！';
    }
}

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