Laravel Eloquent分表方法并使用模型关联的实现(2)

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Relations\HasMany;

class Book extends Model
{
  public function chapters ()
  {
    /*
    * books表的id和chapters表中的book_id关联
    * 一对多关系（一本书对应多条章节）
    */
    $instance = new Chapter();
    $instance->setSuffix($this->id % 10);

    $foreignKey = $instance->getTable . '.' . $this->getForeignKey();
    $localKey = $this->getKeyName();

    return new HasMany($instance->newQuery(), $this, $foreignKey, $localKey);
  }
}